The Boiler Control 274 operates up to four on/off boilers to provide outdoor reset operation, domestic hot water and setpoint
operation with priority. When operating as a tN4 System Control, the 274 can connect with up to 24 tN4 devices on a single
boiler bus. The 274 has primary pump sequencing capabilities along with a flow proof or combustion air damper proof
demand.
Additional functions include:
tN4 Compatible
•
24 Hour, 5-1-1, 7 Day Schedule
•
Flow or Combustion Air Proof
•
Four On/Off Boilers
•
Equal Run Time Rotation
•
Primary Pump Sequencing
•
DHW Operation
•
Optional DHW Sensor
•
Setpoint Operation
•
tN4
Boiler
Bus
VIEW
1
Primary
DHW
13
24
MenuItem
Boiler Control 274
One tN4, Four Stage Boiler & DHW / Setpoint
Do not apply power
2513
46
BRet/
ComtN4
OutCom
Boil
+
–
DHW
Sup
Boiler Demand
DHW / Setpoint Demand
Proof Demand
Zone Load Shedding
Priority Override
EMS Input Signal
Relay1Relay2Relay3Relay4C.A. /
Setback
Rotate
Off
EMS
Demands
Exercise
Off
Test
Modes
1 Up to 4 On/Off Boilers
2 Up to 2 On/Off Boilers & 2 Pumps
3 Up to 2 Lo/Hi Boilers
4 1 Lo/Hi Boiler & 1 Pump
5 1 Three Stage Boiler & Pump
6 1 Four Stage Boiler
Made in Canada by
tekmar Control Systems Ltd
tektra 1020-02
Power 115 V ±10% 60 Hz 7 VA, 1150 VA max.
Relays 230 V (ac) 5 A 1/3 hp
Demands 20 to 260 V (ac) 2 VA
Signal wiring must be rated at least 300 V.
20
Alert
1719109121114131615
DHW
/ P2
18
Prim
Power
P1 L N
Boiler
Demand
222187
Pump Sequencer
Fixed Last
Fixed Lead
First On / Last Off
First On / First Off
off
red
red
For maximum heat,
press and hold Tes t
button for 3 seconds.
The Control Settings section of this brochure describes
the various items that are adjusted and displayed by the
control. The control functions of each adjustable item are
described in the Sequence of Operation.
The control uses a Liquid Crystal Display (LCD) as the
method of supplying information. You use the LCD in
order to setup and monitor the operation of your system.
The control has four push buttons (Menu, Item, ▲, ▼) for
selecting and adjusting settings. As you program your
control, record your settings in the ADJUST menu table,
which is found in the second half of this brochure.
Menu
All of the items displayed by the control are organized
into five menus (View, Adjust, Time, Schedule, and Misc).
These menus are listed on the top left hand side of the
display (Menu Field). To select a menu, use the Menu
button. By pressing and releasing the Menu button, the
display sequences between the five menus. Once a menu
is selected, there will be a group of items that can be viewed
within the menu.
Item
The abbreviated name of the selected item will be displayed
in the item field of the display. To view the next available
item, press and release the Item button. Once you have
reached the last available item in a menu, pressing and
releasing the Item button will return the display to the first
item in the selected menu.
The items can be quickly scrolled through by holding the
Item button and then pressing the ▼ button. To rapidly
scroll through the items in the reverse order, hold the
Item button and press the ▲ button.
Adjust
To make an adjustment to a setting in the control, begin by
selecting the ADJUST, TIME, SCHEDULE or MISC menu
using the Menu button. Then select the desired item using
the Item button. Finally, use the ▲, and / or ▼ button to make
the adjustment.
Additional information can be gained by observing the
Status field of the LCD. The status field will indicate
which of the control’s outputs are currently active. Most
symbols in the status field are only visible when the
VIEW menu is selected.
Page 3
Display
Menu Field
Displays the
current menu
Status Field
Displays the current
status of the
inputs, outputs and
control’s
operation
Buttons
Selects Menus, Items
and adjusts settings
Number Field
Displays the current value
of the selected item
MenuItem
Item Field
Displays the current
item selected
Symbol Description
PRIMARY PUMP
Displays when primary pump 1 or
primary pump 2 is in operation
BOILER
Displays which boiler stage is
operating
LOCK
Displays when adjusting Access level if
Switch is set to lock.
WARNING
Displays when an error exists.
COMMUNICATION BUS
Displays when tN4 thermostats are
connected.
DHW PUMP
Displays when the DHW Pump is
operating
Schd Wake
UnOcc Sleep
Away
BOILER PUMP
Displays when the boiler pump 1, 2, 3,
or 4 are operating
COMBUSTION AIR DAMPER
Displays when the combustion air
damper relay is closed
SCHEDULE MASTER
Displays when the 274 is a schedule
master
WARM WEATHER SHUT DOWN
Displays when the control is in warm
weather shut down
MINIMUM & MAXIMUM
Displays when the boil target or the boil
supply is at a minimum or maximum
Displays the control operation as
indicated by the text
Page 4
Access Level
The access level restricts the number of Menus, Items,
and Adjustments that can be accessed by the user. The
Access Level setting is found in the Miscellaneous (MISC)
Menu. Select the appropriate access level for the people
who work with the control on a regular basis. There are
three Access Level Settings:
•
User (USER): Select this access level to limit the highest
number of settings available to the end user.
Installer (INST): Select this access level to limit some of
•
the settings available to the installer. This is the factory
default access level.
Advanced (ADV): Select this access level to have complete
•
access to all of the control settings. In the following menu
tables, the appropriate access level needed to view each
item is shown in the Access column.
Note: the Lock / Unlock switch on the front of the control
must be set to unlock to change the access level.
Sequence of Operation
In order for the control to have a target water temperature there must be a demand. There are three different demands the
control can have: boiler demand, DHW demand, and setpoint demand.
Boiler Demand Section A
Once the control receives a boiler demand it calculates a
target water temperature based on the characterized heating
curve to provide outdoor reset for space heating. The control
can receive a boiler demand three different ways:
1. By applying 20-260 V (ac) to the boiler demand
terminals (21 & 22) when the DIP switch is set to
Demands.
2. From an Energy Management System (EMS) by
applying a 0-10 or 2-10 V (dc) signal to terminals 2 &
3 when the DIP switch is set to EMS.
3. From a tN4 device. This requires a tN4 thermostat to
be wired to terminals 1 & 2 so that the call for heat
can go over the communication bus.
20-260 V (ac)
2221
Boiler
Demand
Demand
23
OutCom
+
–
OROR
0-10 or
2-10 V (dc)
from EMS
21
tN4 Com
–
tN4
Demand
Outdoor Reset Section B
In a heating system, the rate of heat supplied to the building
must equal the rate at which heat is lost. If the two rates are
not equal, the building will either cool off or over heat.
The rate of building heat loss depends mostly on the outdoor
temperature. Outdoor Reset allows a hot water heating
system to increase the water temperature, adding heat to
the building, as the outdoor temperature drops. The rate
at which the water temperature is changed as a function
of outdoor temperature is defined by the characterized
heating curve.
Characterized Heating Curve
A characterized heating curve determines the amount the
target water temperature is raised for every 1° drop in outdoor
air temperature.
The characterized heating curve takes into account the
type of terminal unit that the system is using. Since different
types of heating terminal units transfer heat to a space using
different proportions of radiation, convection and conduction,
the supply water temperature must be controlled differently.
The control uses the terminal unit setting to vary the supply
water temperature to suit the terminal unit being used. This
improves the control of the air temperature in the building.
Boiler Characterized Heating Curve
Boiler
Design
Terminal
Unit
Outdoor
Design
Boiler
Indoor
Decreasing Outdoor Temperatures
Increasing Water Temperatures
Page 5
Terminal Unit Setting in Adjust Menu
Select the appropriate terminal unit in the adjust menu.
This will change the shape of the characterized heating
curve to better match the heat transfer properties of that
specific terminal unit.
Hydronic Radiant Floor (HRF1)
A heavy or high mass, hydronic radiant floor system. This
type of a hydronic radiant floor is embedded in either a thick
concrete or gypsum pour. This heating system has a large
thermal mass and is slow acting.
Hydronic Radiant Floor (HRF2)
A light or low mass, hydronic radiant floor system. Most
commonly, this type of radiant heating system is attached to
the bottom of a wood sub floor, suspended in the joist space,
or sandwiched between the subfloor and the surface. This
type of radiant system has a relatively low thermal mass
and responds faster than a high mass system.
Radiator (RAD)
A radiator terminal unit has a large heated surface that is
exposed to the room. A radiator provides heat to the room
through radiant heat transfer and natural convection.
Baseboard (BASE)
A baseboard terminal unit is similar to a radiator, but has
a low profile and is installed at the base of the wall. The
proportion of heat transferred by radiation from a baseboard
is greater than that from a fin-tube convector.
Boiler Terminal Unit Defaults
When a terminal unit is selected for boiler zones, the
control loads default values for the boiler design, boiler
maximum supply, and boiler minimum supply temperatures.
The factory defaults can be changed to better match the
installed system. Locate the Boiler Terminal Unit setting in
the Adjust menu.
Fancoil (COIL)
A fancoil terminal unit or air handling unit (AHU) consisting
of a hydronic heating coil and either a fan or blower. Air is
forced across the coil at a constant velocity by the fan or
blower and is then delivered into the building space.
Fin–tube Convector (CONV)
A convector terminal unit is made up of a heating element
with fins on it. This type of terminal unit relies on the natural
convection of air across the heating element to deliver
heated air into the space. The amount of natural convection
is dependant on the supply water temperature to the heating
element and the room air temperature.
Terminal Unit
High Mass Radiant
Low Mass Radiant
Fancoil
Fin-Tube Convector
Radiator
Baseboard
BOIL DSGNBOIL MAXBOIL MIN
120°F (49°C)140°F (60°C)OFF
140°F (60°C)160°F (71°C)OFF
190°F (88°C)210°F (99°C)140°F (60°C)
180°F (82°C)200°F (93°C)140°F (60°C)
160°F (71°C)180°F (82°C)140°F (60°C)
150°F (76°C)170°F (77°C)140°F (60°C)
Room Setting in Adjust Menu
The Room setting is the desired room air temperature, but
it is not measuring a room temperature sensor. Instead,
the Room setting parallel shifts the heating curve up or
down to change the target water temperature. Adjust the
Room setting to increase or decrease the amount of heat
available to the building. Once the heating curve has been
set up properly, the Room setting is the only setting that
needs to be adjusted. The default Room setting is 70°F
(21°C), and it can be adjusted for both the occupied and
unoccupied periods.
The outdoor design temperature is typically the coldest
outdoor air temperature of the year. This temperature is
used when doing the heat loss calculations for the building
and is used to size the heating system equipment. If a cold
outdoor design temperature is selected, the supply water
temperature rises gradually as the outdoor temperature
drops. If a warm outdoor design temperature is selected,
the supply water temperature rises rapidly as the outdoor
temperature drops.
Boiler Indoor Setting in Adjust Menu
The boiler indoor design temperature is the indoor
temperature the heating designer chose while calculating the
heat loss for the boiler water heated zones. This temperature
is typically 70°F (21.0°C). This setting establishes the
beginning of the boiler characterized heating curve.
Boiler Design Setting in Adjust Menu
The boiler design supply temperature is the boiler water
temperature required to heat the zones at the outdoor design
temperature, or on the typical coldest day of the year.
(Default automatically changes based on terminal unit
setting)
Warm Weather Shut Down (WWSD) Setting in Adjust
Menu
Warm Weather Shut Down disables the heating system when
the outdoor air temperature rises above this programmable
setting. When the control enters into WWSD, the LCD will
indicate this in the status field. WWSD is only available
when the DIP switch = Demands. The boilers will operate
when a Domestic Hot Water (DHW) demand or a Setpoint
Demand is present.
Boiler Operation Section C
The 274 is able to operate up to four on/off boilers as a heat
source. For proper operation of the boilers, the 274 must be
the only control that determines when a boiler is to fire.
*Important note: The boiler operator, or aquastat, remains
in the burner circuit and acts as a secondary upper limit
on the boiler temperature. The boiler aquastat temperature
setting must be adjusted above the 274’s boiler maximum
setting in order to prevent short cycling of the burner.
Mode
The 274 control is capable of staging single stage, two
stage, three stage and four stage on/off heat sources. As
well, in certain modes of operation, the control is capable
of controlling the individual boiler pumps. The control has 6
modes of operation based on the type of staging and pump
operation that is desired. The following describes the modes
of operation.
Mode 1: 4 Single stage boilers and primary pump.
Mode 2: 2 Single stage boilers with individual boiler
pumps and primary pump.
Mode 3: 2 Two stage boilers and a primary pump.
Mode 4: 1 Two stage boiler and individual pump.
Mode 5: 1 Three stage boiler and individual pump.
Mode 6: 1 Four stage boiler and primary pump.
Relay 1Relay 2Relay3Relay 4
Mode 1
Mode 2
Mode 3
Mode 4
Mode 5
Mode 6
Boiler 1Boiler 2Boiler 3Boiler 4
Boiler 1Boiler 1
Boiler 1
Stage 1
Boiler 1
Stage 1
Boiler 1
Stage 1
Boiler 1
Stage 1
Supply
Supply
Sensor
Sensor
Primary
Primary
Pump
Pump
Return
Return
Sensor
Sensor
Pump
Boiler 1
Stage 2
Boiler 1
Stage 2
Boiler 1
Stage 2
Boiler 1
Stage 2
Boiler 2Boiler 2
Boiler 2
Stage 1
Boiler 1
Pump
Boiler 1
Stage 3
Boiler 1
Stage 3
Boiler
Boiler
Pumps
Pumps
Pump
Boiler 2
Stage 2
not used
Boiler 1
Pump
Boiler 1
Stage 4
Boiler Target Temperature
The boiler target temperature is determined by connected tN4
devices or by a Boiler, DHW or Setpoint demand received
by the control. An Energy Management System (EMS) can
also give a boiler target. The tN4 devices determine the
highest water temperature required and then request this
temperature on the tN4 boiler bus. The temperature request
creates a Boiler Demand and this is indicated on the display.
A DHW demand and a Setpoint demand have temperature
settings to which the boilers are operated to meet and are
able to override the tN4 bus temperature if required. The
control displays the temperature that it is currently trying to
maintain as the boiler supply temperature in the View menu.
If the control does not presently have a requirement for heat,
it does not show a boiler target temperature. Instead, “– – –”
is displayed in the LCD.
The boiler minimum is the lowest temperature that the
control is allowed to use as a boiler target temperature.
During mild conditions, if the control calculates a boiler
target temperature that is below the boiler minimum setting,
the boiler target temperature is adjusted to at least the
boiler minimum setting. The MIN segment is displayed in
the LCD while viewing the boiler supply or target and when
the boiler target is boiler minimum and the boiler supply is
less than boiler minimum plus 5°F (2.5°C). Set the Boiler
Minimum setting to the boiler manufacturer’s recommended
temperature.
Boil MIN + 5°F (2.5°C)
Boiler Differential
e
e
r
B
B
o
o
i
i
l
l
W
W
a
a
e
e
T
T
t
t
e
e
r
r
MIN segment on
r
u
u
t
t
a
a
r
r
e
e
p
p
m
m
Boil MIN
MED
The MED setting is selected if the boiler that is used has
a medium thermal mass. This means that the boiler either
has a large water content and a low metal content or a
low water content and a high metal content. This is typical
of many modern residential cast iron boilers or steel tube
boilers.
The Med mass setting provides a moderate response to
the heating system.
HI
The HI setting is selected if the boiler that is used has a
high thermal mass. This means that the boiler has both
large water content and a large metal content. A boiler that
has a high thermal mass is relatively slow in coming up to
temperature. This is typical of many commercial cast iron
and steel tube boilers.
The Hi mass setting provides a slow response to the
heating system.
Boiler Maximum Setting in Adjust Menu
The boiler maximum is the highest temperature that the
control is allowed to use as a boiler target temperature.
The MAX segment is displayed in the LCD while viewing
the boiler supply or target and when the boiler target is
boiler maximum and the boiler supply is greater than boiler
maximum minus 5°F (2.5°C). Set the boiler maximum
setting to the boiler manufacturer’s recommended temperature. At no time does the control operate the boiler
above 248°F (120°C).
MAX
segment
on
B
B
o
o
i
i
l
l
W
W
a
a
e
e
T
T
t
t
r
r
e
e
e
e
p
p
m
m
e
e
r
r
u
u
t
t
a
a
r
r
MAX
segment
on
Boil MAX
Boil MAX – 5°F (2.5°C)
Boiler Differential
Stage Delay Setting in Adjust Menu
The Stage Delay is the minimum time delay between the
firing of each stage. After this delay has expired the control
can fire the next stage if it is required. This setting can be
adjusted manually or set to an automatic setting. When the
automatic setting is used, the control determines the best
Rotation
The Rotate feature changes the firing order of the boilers
whenever one boiler accumulates 48 hours more run time
than any other boiler. Rotation will be forced if any boiler
accumulates 60 hours more run time. After each rotation,
the boiler with the least running hours is the first to fire and
the boiler with the most running hours is the last to fire.
This function ensures that all of the boilers receive equal
amounts of use. When the Rotate / Off DIP switch is set
to the Off position, the firing sequence always begins with
lowest boiler to the highest boiler.
12
720 hours
672 hours
21
672 hours
720 hours
To reset the rotation sequence (without regard to historical
running hours), toggle the Rotation DIP Switch Off for 3
seconds and on again. Note that the running hours (see
Run Time) in the View menu also need to be reset if you
want the rotation sequence and running hours display to
be synchronized.
stage delay based on the operation of the system.
Boiler Mass Setting in Adjust Menu (per boiler)
Match the boiler mass setting with the thermal mass
characteristics of each boiler. The boiler mass settings
also adjusts the inter-stage delay time when operating with
an automatic differential.
LO
The LO setting is selected if the boiler that is used has
a low thermal mass. This means that the boiler has very
small water content and has very little metal in the heat
exchanger. A boiler that has a low thermal mass comes
up to temperature quite rapidly when fired. This is typical
of many copper fin-tube boilers.
The Lo mass setting provides a fast response to the heating
system.
In some applications, it may be desirable to have the last
boiler fire last at all times while the firing sequence of
the remaining boilers is changed using Equal Run Time
Rotation. This configuration is typical of installations where
the boiler plant includes higher efficient boilers and a single
less efficient boiler. The lesser efficient boiler is only desired
to be operated when all other boilers in the plant are on
and the load cannot be satisfied. This rotation option is
selected by setting the Fixed Last / Off DIP switch to Fixed
Last. With a fixed last rotation, the last boiler is the last to
stage on and the first to stage off.
Page 8
Fixed Lead & First On / First Off
In some applications, it may be desirable to have the first
boiler fire first at all times while the firing sequence of the
remaining boilers is changed using Equal Run Time Rotation.
This rotation option is selected by setting the Fixed Lead /
Off DIP switch to the Fixed Lead position.
When using the Fixed Lead rotation option, a selection must
be made between First On / Last Off and First On / First Off
using the DIP switch.
When First On / First Off is selected, the lead boiler is always
staged on first and staged off first. This configuration is typical
of installations where the boiler plant includes similar boilers
but the first boiler is required to be the first to fire in order to
establish sufficient draft for venting.
Fixed Lead & First On / Last Off
When First On / Last Off is selected, the lead boiler is always
staged on first and staged off last. This configuration is typical
of installations where the boiler plant includes a single higher
efficient boiler with lesser efficient boilers. The lead boiler
is the high efficiency boiler, therefore it is the last boiler to
be sequenced off.
Boiler Run Time in View Menu
The running time of each boiler is logged in the view menu.
To reset the running time, select the appropriate Boiler Run
Time in the View menu and press and hold the Up and Down
buttons simultaneously until CLR is displayed.
Boiler Differential Setting in Adjust Menu
An On/Off heat source must be operated with a differential
in order to prevent short cycling. The boiler differential can
be fixed or automatically determined by the control. The Auto
Differential setting balances the amount of temperature swing
in the boiler supply temperature with boiler on times, off times,
and cycle times. This reduces potential short cycling during
light load conditions.
Manual Differential
Differential = 10°F (6°C)
165°F (74°C)
160°F (71°C)
155°F (68°C)
Boiler
On
Boiler
On
Target + 1/2 Differential
Target
Target – 1/2 Differential
Automatic Differential
Off
Differential
Time
On
Heating Load
Boiler Staging Mode - Lo/Hi or Lo/Lo in Adjust Menu
When using multi-stage boilers, a selection must be made
regarding the staging order of the boiler(s). This adjustment
is made in the ADJUST menu of the control.
Lo/Hi: If the Lo/Hi staging option is selected the control stages
in sequence all of the stages in a single boiler. Once all of the
stages are turned on, the control then stages in sequence all
of the stages of the next boiler in the rotation sequence.
Lo/Lo: If the Lo/Lo staging option is selected, the control
stages all of the Lo stage outputs in all of the boilers first.
Once all of the boilers are operating on their Lo stages, the
control then operates the second stage in each boiler in the
same order.
Boiler Fire Delay Setting in Adjust Menu
(per boiler)
The Boiler Fire Delay sets the time it takes for the boiler to
generate flame from the time the boiler turns on.
Boiler Contact Closed
Fire Delay
Burner On
Time
Combustion Air and Alert Settings Section D
Relay Setting in Adjust Menu (C.A. Damper / Alert)
The control includes an auxiliary relay that can be used either
for a combustion damper/venting device or an Alert. Selection
is made through the Relay item in the Adjust menu.
When the Relay is set to Alert, terminals 15 and 16 close
whenever a control or sensor error is detected, or when a
warning or limiting condition is detected. When the alert
contact closes, refer to the Error Messages section of this
brochure to determine the cause of the alert and how to
clear the error.
Page 9
Boiler Alarm
For the Boiler Alarm item to appear in the Adjust menu, the
Relay must be set to Alert. If no temperature increase is
detected at the boiler supply sensor within this delay period,
the Alert relay will close and the control will display the Boiler
Alarm error message. All boilers continue to operate if this
error is present. To clear the error, press and hold the up and
down buttons simultaneously for 5 seconds while viewing the
error message in the View menu.
Combustion Air (C.A.) Damper
When the Relay is set to Damper, terminals 15 and 16 operate
a combustion air damper / fan motor or power vent motor. The
Relay closes once a demand is received and the control has
determined that one or more boilers need to be turned on.
Combustion Air Proof Demand Setting in Adjust Menu
The proof demand can be used to prove a combustion air
or venting device if set to C.A. Boiler operation cannot occur
until the proof demand is present. If the proof demand is lost
during operation, the boiler plant is sequenced off.
Combustion Air Proof Demand Delay Setting in Adjust
Menu
The control includes a time delay that is associated with
the proof demand feature in order to determine if the proof
device is functional. Once the C.A. relay closes, the control
allows for this delay to receive the proof demand. If the proof
demand is not received within the delay time, the control will
display an error message.
Combustion Air Damper Delay Setting in Adjust Menu
If the Proof Demand function is set to F P (flow proof) or
OFF, boiler sequencing only occurs once a user adjustable
time delay elapses.
Combustion Air Post Purge
There is a fixed 15 second post purge of the C.A. relay
after the last boiler has turned off, or demand is removed. If
there is a heat demand still present once the last boiler has
turned off, the control can look at the error and determine
if sequencing is to occur in a “short” period of time. If the
control does anticipate staging, the C.A. relay will remain
on. Otherwise, the C.A. relay will be turned off once the 15
second post purge elapses.
Combustion Air Proof Demand Test
The control includes a C.A. proof demand test in order to
determine if the proving device has failed. If the C.A. damper
contacts are opened, the flow proof demand should not be
present after 4 minutes. If the flow proof demand remains,
the control will display an error message.
Domestic Hot Water Operation Section E
DHW operation is only available when the Pump Sequencer
DIP Switch is set to Off.
DHW Demand
DHW Demands come from one of three sources: an external
aquastat, a DHW tank sensor, or a tN4 DHW control.
Once the control detects a DHW Demand, the DHW Demand
segment is displayed in the LCD. If an External Powered
DHW Demand is applied while the DHW sensor is enabled
in the 274, an error message is generated and both demands
are ignored.
A DHW demand from a tN4 Setpoint Control can coexist with
another DHW demand without generating an error message.
The 274 will then use the higher of the two targets.
Powered DHW Demand
The control registers a DHW Demand when a voltage
between 20 and 260 V (ac) is applied across the DHW
Demand terminals 23 and 24. An aquastat or setpoint control
is used to switch the DHW Demand circuit. Program a DHW
Exchange temperature for the Occupied and UnOccupied
events in the Adjust Menu.
• DHW Sensor must be set to Off.
DHW Sensor
The control can register a DHW Demand when A DHW
Sensor is wired to terminals 5 and 6. Once the DHW Sensor
drops 1/2 of the DHW Differential setting below the DHW
Setpoint, the control registers a DHW Demand. Program a
DHW Tank temperature for the Occupied and UnOccupied
events in the Adjust Menu.
The DHW Sensor must be set to On. There cannot be
•
an externally powered DHW demand when using a DHW
sensor.
tN4 Setpoint Control in DHW Mode
The control can register a DHW Demand when a tN4 Setpoint
Control in DHW Mode is wired to terminals 1 and 2. The
DHW Demand is sent over the tN4 communication bus when
the Setpoint Control calls for heat. Program a DHW tank
temperature for the Occupied and UnOccupied events and
the desired supply water temperature required on the tN4
bus in the Adjust Menu of the tN4 Setpoint Control.
Due to large differences between the heating load and the
DHW load, a separate DHW differential should be used
whenever a DHW Demand is present. This will improve
staging and boiler cycling. When using a DHW Sensor, a
DHW Demand is registered when the DHW sensor drops 1/2
of the DHW Differential setting below the DHW setting. The
DHW Demand is satisfied once the DHW Sensor rises 1/2
of the DHW Differential setting above the DHW setting.
OFF
DHW
Differential
ON
DHW Target
Mode OFF / No DHW Generation
All DHW demands are ignored. If this mode is selected while
DHW generation is underway, all DHW operation stops.
Mode 1 - DHW in Parallel with No Priority
When a valid DHW Demand is present, the DHW relay
(terminal 17) turns on. The primary pump can operate
when a Boiler Demand is present. It is assumed that the
DHW pump will provide adequate flow through the heat
exchanger and the boiler. Heating zones are unaffected
by DHW operation.
Mode = 1
Boiler Target Temperature during a DHW Demand
If a Powered DHW Demand is present, the boilers are
operated to maintain the DHW Exchange temperature. If a
DHW sensor demand is present, the boilers are operated
to maintain a temperature 40°F above the DHW tank
temperature. If a tN4 demand is present, the primary
pump is turned on according to the device’s reported
requirements and the boilers are operated to maintain the
devices requested target on the bus. The DHW Demand
overrides the boiler reset target temperature, except when
the boiler reset target is higher than the DHW target.
Regardless of DHW settings and requested targets, the
boilers will maintain a supply temperature no higher than
the Boil MAX setting.
DHW During UnOccupied
When using a Powered DHW Demand, the control has a
DHW Exchange UnOccupied setting that allows the installer
to select On or Off. When set to On, and the control receives
a DHW Demand during an UnOccupied or Sleep period,
the control continues operation of the DHW system as it
would during the Occupied and Wake periods. When set to
Off, the control will ignore a DHW Demand for the duration
of the UnOccupied and Sleep periods.
When using a DHW Sensor, a second DHW temperature
setting is available for the UnOccupied or Sleep period.
DIP Switch must be set to Setback to view UnOccupied
items.
During the Away Scene, DHW demands are ignored.
DHW
Pump
Primary
Pump
Mode 2 - DHW in Parallel with Priority
When a valid DHW Demand is present, the DHW relay
(terminal 17) turns on. The primary pump can operate
when a Boiler Demand is present. If the boilers are unable
to maintain the boiler target temperature, space heating
zones are shut off sequentially using tN4 communication
in order to provide priority to the DHW tank. For non-tN4
systems, the primary pump shuts off to provide priority. It
is assumed that the DHW pump will provide adequate flow
through the heat exchanger and the boiler.
Mode = 2
OFF
DHW
Pump
Primary
Pump
DHW Mode Setting in the Adjust Menu
The control has six different DHW Modes that affect pump
operation. The required DHW Mode setting will depend on
the piping arrangement of the DHW tank and whether or
not priority for DHW is necessary. DHW Priority stops or
limits the delivery of heat to the building heating system
while the DHW tank calls for heat. This allows for quick
recovery of the DHW tank.
Mode 3 - DHW in Primary/Secondary with No Priority
When a valid DHW Demand is present, the DHW relay
(terminal 17) and Primary Pump relay (terminal 18) turn
on. Heating zones are unaffected by DHW operation. This
mode can be used if the DHW tank is piped in parallel and
a DHW valve is installed (need to use an external relay to
power the valve with 24 V (ac) since the DHW pump output
is a 120 V (ac) powered output).
Mode = 3
DHW
Pump
Primary
Pump
Mode 4 - DHW in Primary/Secondary with Priority
When a valid DHW Demand is present, the DHW relay
(terminal 17) and Primary Pump relay (terminal 18) turn
on. If the boilers are unable to maintain the boiler target
temperature, space heating zones are shut off sequentially
using tN4 communication in order to provide priority to the
DHW tank.
Mode 5 - DHW in Parallel / Last Boiler with Priority
When a valid DHW Demand is present, the DHW relay
(terminal 17) turns on and boiler pump 4 turns off. The control
uses the DHW Exchange Supply Sensor in order to measure
the boiler supply temperature supplied to the indirect tank.
There are two boiler target temperatures, one for the heating
system (BOIL TARGET) and one for the indirect DHW system
(BOIL DHW TARGET). In this mode, the DHW Demand can
only be provided from an External Powered Demand or tN4
Setpoint Control in DHW mode.
All boilers are used for space heating requirements
•
Boiler 2 is used for DHW when there is a DHW demand
•
The dedicated DHW boiler is always boiler 2 (relay 3),
•
even if there are less than 4 boilers.
If boiler 2 is disabled and mode 5 is selected then the
•
dedicated DHW boiler (boiler 2) will not operate.
This DHW mode is only available when control is in
•
Mode = 2
Mode = 5
DHW Exchange
Supply Sensor
DHW Pump
ON
Boiler
OFF
Supply
Sensor
Mode = 4
DHW
Pump
Primary
Pump
OFF
Primary
Pump
Mode 6 – Dedicated DHW
When a valid DHW Demand is present from the DHW
Sensor, the primary pump relay turns on. The DHW Relay
in this mode is used as the DHW recirculation pump and
operates continuously in the Occupied period and cycles
with the primary pump in the UnOccupied period. The boiler
plant is sequenced based only on the DHW Sensor.
All boilers are used for DHW requirements
•
Requires DHW demand from DHW sensor
•
DHW Pump Relay is used for DHW recirculation pump
DHW Priority Override applies to DHW MODE 2 and 4, as
well as Mode 5 if there is a tN4 device with DHW. It prevents
the building from cooling off too much or the possibility of
a potential freeze up during DHW priority.
When set to auto, the priority time is calculated based
on outdoor temperature. At or below the design outdoor
temperature, 15 minutes are allowed for DHW priority. At
or above 70°F, 2 hours are allowed for DHW priority. The
time allowed for DHW priority varies linearly between the
above two points. There is a manual setting also available
in the adjust menu.
The priority timer does not start timing until priority is selected
and both a DHW Demand and a Boiler Demand exist together.
Once the allowed time for priority has elapsed, the control
overrides the DHW priority and resumes space heating.
Automatic Priority Override
2 hours
15 mins
70°F (21°C)
Design Temperature
Conditional DHW Priority
If the boiler supply temperature is maintained at or above
the required temperature during DHW generation, this
indicates that the boilers have enough capacity for DHW
and possibly heating as well. As long as the boiler supply
temperature is maintained near the target, DHW and heating
occurs simultaneously.
DHW Post Purge
After the DHW Demand is removed, the control performs
a purge. The control shuts off the boilers and continues to
operate the DHW Pump and the primary pump if applicable.
This purges the residual heat from the boilers into the
DHW tank. The control continues this purge until one of
the following occurs:
1. A Boiler Demand is detected
2. The boiler supply drops 20°F (11°C) below the DHW
target temperature
3. The DHW tank temperature rises above the DHW
setpoint plus 1/2 DHW Differential
4. Two minutes elapse
DHW Mixing Purge
After DHW operation, the boiler is extremely hot. At the same
time, the heating zones may have cooled off considerably
after being off for a period of time. When restarting the
heating system after a DHW demand with priority, the
control shuts off the boiler and continues to operate the
DHW pump while the primary pump is turned on. This allows
some of the DHW return water to mix with the cool return
water from the zones and temper the boiler return water.
DHW with Low Temperature Boilers
If DHW heating is to be incorporated into a low temperature
system such as a radiant floor heating system, a mixing
device is often installed to isolate the high DHW supply
temperature from the lower system temperature. If a mixing
device is not installed, high temperature water could be
supplied to the low temperature system while trying to
satisfy the DHW demand. This may result in damage to
the low temperature heating system.
The control is capable of providing DHW heating in such a
system while minimizing the chance that the temperature
in the heating system exceeds the design supply water
temperature. In order to do this, the following must be true:
tN4 Present
•
DHW MODE 2 or 4
•
Boil MIN OFF
•
On a call for DHW, the control provides DHW priority by
sending a message on the boiler temperature bus to the tN4
thermostats to shut off the heating zones for a period of time.
The length of time is based on the outdoor air temperature as
described in the DHW Priority Override section. However, if
the DHW Demand is not satisfied within the allotted time, the
boiler shuts off and the heat of the boiler is purged into the
DHW tank. A DHW mixing purge occurs in order to reduce
the boiler water temperature and once the boiler supply
temperature is sufficiently reduced, the DHW Pump contact
shuts off. The heating system zones are allowed to turn on for
a period of time to prevent the building from cooling off. After
a period of heating, and if the DHW Demand is still present,
the control shuts off the heating system and provides heat
to the DHW tank once again.
DHW Boilers Setting in Adjust Menu
Select the number of boilers to use for DHW generation.
Setpoint operation is only available when DHW Mode is
set to Off.
The control can operate to satisfy the requirements of a
setpoint load in addition to a space heating load. A setpoint
load overrides the current outdoor reset temperature in
order to provide heat to the setpoint load.
Setpoint Demand
Setpoint Demands come from one of two sources: a
Powered Setpoint Demand, or a tN4 Setpoint Control.
Powered Setpoint Demand
The control registers a Setpoint Demand when a voltage
between 20 and 260 V (ac) is applied across the Setpoint
Demand terminals 23 and 24. An aquastat or setpoint
control is used to switch the Setpoint Demand circuit.
Program a Setpoint target for the Occupied and UnOccupied
events in the Adjust Menu.
• DHW Mode must be set to Off.
tN4 Setpoint Control
The control can register a Setpoint Demand when a tN4
Setpoint Control is wired to terminals 1 and 2. The Setpoint
Demand is sent over the tN4 communication bus when
the Setpoint Control calls for heat. Program a Setpoint
temperature for the Occupied and UnOccupied events and
the desired supply water temperature required on the tN4
bus in the Adjust Menu of the tN4 Setpoint Control.
• DHW Mode must be set to Off.
A demand from a tN4 Setpoint Control can coexist with another
setpoint demand without generating an error message. The
274 will then use the higher of the two targets.
DIP Switch must be set to Setback to view UnOccupied
items.
During the Away Scene, Setpoint demands are ignored.
Setpoint Mode Setting in the Adjust Menu
The control has four different Setpoint Modes that affect
pump operation. The required Setpoint Mode setting will
depend on the piping arrangement and whether or not
priority is necessary. Setpoint Priority stops or limits the
delivery of heat to the building heating system while the
Setpoint load calls for heat. This allows for quick recovery
of the Setpoint load.
Mode OFF - No Setpoint Operation
All Setpoint demands are ignored. If this mode is selected
while Setpoint operation is underway, all Setpoint operation
ceases.
Mode 1 - Setpoint in Parallel with No Priority
Whenever a Setpoint Demand is present, the boilers are
operated to maintain the setpoint target. The primary
pump does not turn on, but may operate based on a Boiler
Demand. It is assumed that the Setpoint pump will provide
adequate flow through the heat exchanger and the boiler.
Mode = 1
Setpoint
Primary
Pump
Boiler Target Temperature during a Setpoint Demand
If a Powered Setpoint Demand is present, the boilers are
operated to maintain the Setpoint target. If a tN4 demand
is present, the primary pump is turned on according to
the device’s reported requirements and the boilers are
operated to maintain the devices requested target on the
bus. The Setpoint Demand overrides the boiler reset target
temperature, except when the boiler reset target is higher
than the Setpoint target. Regardless of Setpoint settings
and requested targets, the boilers will maintain a supply
temperature no higher than the Boil MAX setting.
Setpoint During UnOccupied
When using a Powered Setpoint Demand, the control has
a Setpoint UnOccupied setting that allows the installer to
select On or Off. When set to On, and the control receives
a Setpoint Demand during an UnOccupied or Sleep period,
the control continues operation of the Setpoint system as
it would during the Occupied and Wake periods. When set
to Off, the control will ignore a Setpoint Demand for the
duration of the UnOccupied and Sleep periods.
Mode 2 - Setpoint in Parallel with Priority
When a Setpoint Demand is present, the boilers are
operated to maintain the setpoint target. The primary
pump can operate when a Boiler Demand is present. If the
boilers are unable to maintain the boiler target temperature,
space heating zones are shut off sequentially using tN4
communication in order to provide priority to the Setpoint
Load. For non-tN4 systems, the primary pump shuts off to
provide priority. It is assumed that the Setpoint pump will
provide adequate flow through the heat exchanger and
the boiler.
Mode 3 - Setpoint in Primary/Secondary with No Priority
Whenever a Setpoint Demand is present, the primary pump
is turned on and the boilers are operated to maintain the
setpoint target.
Mode = 3
Setpoint
Automatic Priority Override
2 hours
15 mins
Primary
Pump
Mode 4 - Setpoint in Primary/Secondary with Priority
Whenever a Setpoint Demand is present, the primary
pump is turned on and the boilers are operated to maintain
the setpoint target. Space heating zones will be shut
off if the boilers are unable to maintain the boiler target
temperature.
Mode = 4
Setpoint
OFF
Primary
Pump
Setpoint Priority Override Setting in Adjust Menu
Setpoint Priority Override applies to SETPOINT MODE 2 and
MODE 4. To prevent the building from cooling off too much or
the possibility of a potential freeze up during setpoint priority,
the control limits the amount of time for setpoint priority.
When set to auto, the priority time is calculated based
on outdoor temperature. At or below the design outdoor
temperature, 15 minutes are allowed for Setpoint priority.
At or above 70°F, 2 hours are allowed for Setpoint priority.
The time allowed for Setpoint priority varies linearly
between the above two points. There is a manual setting
also available in the adjust menu.
The priority timer does not start timing until priority is
selected and both a Setpoint Demand and a Boiler Demand
exist together. Once the allowed time for priority has
elapsed, the control overrides the Setpoint priority and
resumes space heating.
Design Temperature70°F (21°C)
Conditional DHW Priority
If the boiler supply temperature is maintained at or above
the required temperature during setpoint generation, this
indicates that the boiler has enough capacity for setpoint
and possibly heating as well. As long as the boiler target
temperature is maintained, setpoint and heating occur at
the same time.
Setpoint Post Purge
After a tN4 Setpoint Demand is removed, the control
performs a purge. The control shuts off the boilers and
continues to operate the Setpoint Pump and the primary
pump if applicable. This purges the residual heat from the
boilers into the Setpoint load. The control continues this
purge until one of the following occurs:
1. A Boiler Demand is detected
2. The boiler supply drops 20°F (11°C) below the Setpoint
target temperature
The control can accept an external DC signal from an Energy
Management System (EMS) in place of the outdoor sensor.
The control converts the DC signal into the appropriate
boiler target temperature between 50°F (10°C) and 210°F
(99°C) based on the EMS Input Signal and Offset settings.
To use the external input signal, the EMS / Demands DIP
switch must be set to EMS.
An external signal is generated by applying a voltage
between 0 V (dc) and 10 V (dc) across the Out + and Com
– terminals (3 and 2). Voltages that exceed 10 V (dc) will
still be considered a 10 V (dc) signal.
Once voltage is applied, the EMS Input Signal pointer is
displayed in the LCD and the control calculates a boiler
target and closes the primary pump contact. The control
then activates the boiler(s), if required, to maintain the target
supply temperature.
If the EMS signal goes below the minimum voltage, the
EMS Input Signal pointer is turned off in the display. The
boiler target temperature is displayed as “– – –” to indicate
that there is no longer a call for heating. The primary pump
and boiler pumps operate as described in section I.
Input Signal
The control can accept either a 0 - 10 V (dc) signal or a
2 - 10 V (dc) signal. The External Input Signal setting must
be set to the proper setting based on the signal that is being
sent to the control.
0 - 10 V (dc) or 0 - 20 mA
When the 0 - 10 V (dc) signal is selected, an input voltage
of 1 V (dc) corresponds to a boiler target temperature of
50°F (10°C). An input voltage of 10 V (dc) corresponds
0 - 20 mA*0 - 10 V (dc)Boiler Target
4 - 20 mA*2 - 10 V (dc)Boiler Target
CONVERSION TABLE 0 - 10
00– – – (OFF)
2150°F (10°C)
4268°F (20°C)
6386°F (30°C)
84103°F (39°C)
105121°F (49°C)
126139°F (59°C)
147157°F (69°C)
168174°F (79°C)
189192°F (89°C
2010210°F (99°C)
*Requires 500 Ω Resistor in Parallel
CONVERSION TABLE 2 - 10
00– – – (OFF)
4250°F (10°C)
6370°F (21°C)
8490°F (32°C)
105110°F (43°C)
126130°F (54°C)
147150°F (66°C)
168170°F (77°C)
189190°F (88°C)
2010210°F (99°C)
*Requires 500 Ω Resistor in Parallel
to a boiler target temperature of 210°F (99°C). As the
voltage varies between 1 V (dc) and 10 V (dc) the boiler
target temperature varies linearly between 50°F (10°C) and
210°F (99°C). If a voltage below 0.5 V (dc) is received the
boiler target temperature is displayed as “– – –” indicating
that there is no longer a call for heating.
A 0 - 20 mA signal can be converted to a 0 - 10 V (dc) signal
by installing a 500 resistor between the Out + and Com
– terminals (3 and 2).
2 - 10 V (dc) or 4 - 20 mA
When the 2 - 10 V (dc) signal is selected, an input voltage
of 2 V (dc) corresponds to a boiler target temperature of
50°F (10°C). An input voltage of 10 V (dc) corresponds
to a boiler target temperature of 210°F (99°C). As the
voltage varies between 2 V (dc) and 10 V (dc) the boiler
Offset Setting in Adjust Menu
For external input operation, the boiler target (determined
from the external input signal) may be fine tuned. The
Offset setting is used to provide the fine tuning. The Offset
setting may be adjusted ±10°F. When set to 0°F, if the
temperature determined from the external signal is 140°F,
the boiler target will be 140°F. When set to +5°F and with
the same external signal represents 140°F, the boiler target
will be 145°F.
Example
Range = 0 - 10 V (dc)
Input = 7 V (dc) 157°F (69°C)
Offset = +5°F (3°C) + 5°F (3°C)
Boiler Target = 162°F (72°C)
target temperature varies linearly between 50°F (10°C) and
210°F (99°C). If a voltage below 1.5 V (dc) is received the
boiler target temperature is displayed as “– – –” indicating
that there is no longer a call for heating.
A 4 - 20 mA signal can be converted to a 2 - 10 V (dc) signal
by installing a 500 resistor between the Out + and Com
– terminals (3 and 2).
The minimum and maximum settings also apply for external
input operation. For example, if a boiler minimum of 140°F
is set and the external signal received represents 80°F, the
boiler target will be 140°F. The MIN segment will also be
displayed to indicate that a limiting condition is in effect.
This also applies for the MAX segment limit.
Whenever an external signal is used, the control can still
provide all DHW OR Setpoint functions.
The control includes two primary pump outputs with
capability for sequencing. Primary pump sequencing is
activated through a DIP switch. Only primary pump 1
is operated when pump sequencing is turned off, while
primary pumps 1 and 2 are operated in stand-by mode
when pump sequencing is turned on.
The running times of the primary pumps are logged in the
view menu. To reset these values back to zero, press and
hold the up and down button while viewing this item.
Note: once primary pump sequencing is selected, DHW
operation is not available. Setpoint operation, however, is
available if primary pump sequencing is selected.
The primary pumps will operate when the control receives
an appropriate demand:
External Boiler Demand
•
tN4 Boiler Demand and that zone’s thermostat has H1
•
Pump set to On.
DHW Demand and the control is set to DHW Mode 3,
•
4, or 6.
Setpoint Demand and the control is set to Setpoint Mode
•
3 or 4.
The primary pumps also operate when the control is
completing a DHW Purge.
tN4 thermostats can select whether the primary pump is
required to operate or not. tN4 thermostats also include a
thermal actuator setting which can delay the primary pump
for 3 minutes to allow thermal actuators to open.
Flow Proof
The control includes a flow proof demand in order to prove
flow once a primary pump has turned on. In order for
boiler operation to commence, the proof demand must be
present. A flow proof signal is required at all times during
pump operation. A flow proof is generated by applying a
voltage between 20 and 260 V (ac) across the Flow Proof
terminals (30 and 31). Once voltage is applied, the Proof
Demand indicator is turned on in the LCD.
Once a pump contact is turned on, a flow proof signal must
be present before the flow proof delay has expired.
The flow proof demand is selected by setting the Proof
Demand item in the Adjust menu to F P (flow proof).
A flow proof demand can come from a flow switch, pressure
differential switch, current sensing or power sensing device.
Stand-by Operation
The control only operates one primary pump at a time. A
flow proof device can be used to detect when stand-by
pump operation is required.
When a demand is registered, the lead pump is activated,
•
and the control waits for flow to be established within the
flow proof delay time.
If no flow is established, the lead pump is de-activated,
•
the lag pump is activated and the control waits again for
the flow to establish within the flow proof delay time.
If again no flow is established, the lag pump is de-activated
•
and the control stops operation until the error is cleared.
Verify that the pumps and flow proof device are working
correctly before clearing the error.
If the lead pump establishes flow, and fails during
•
operation, the lag pump is activated.
If at any time, one or both pumps fail to prove flow, an
The control waits a period of time to receive a flow proof
demand from the time the primary pump turns on. If the
control does not receive a flow proof demand within that
period of time, the primary pump turns off and the stand-by
primary pump (if active) turns on. The control then waits
that period of time again for the stand-by primary pump to
prove flow. If flow is not proven, the stand-by pump turns
off. The period of time is set through the Proof Demand
‘Pump’ DLY item in the Adjust menu and it is adjustable
between 10 seconds and 3 minutes.
Primary Pump Purge
After the last valid demand is removed, the primary pump
is operated for an additional purging time of at least 20
seconds. If the last demand came from a tN4 zone, the
control sends out a purge message to override the zone
open for the duration of the boiler purge. At the end of
the purge, the zone override is removed so the zone is
allowed to close and turn off the primary pump. If the last
demand came from a non-tN4 zone, the purge period for
the primary pump is adjustable between 10 seconds and
19:55 minutes.
Flow Proof Demand Test
The control includes a flow proof demand test in order to
determine if the flow/pressure device has failed. A flow
proof failure is detected if a flow proof is present after the
pumps have been shut off for more than four minutes. This
can occur if the flow proof device sticks in the on position
even when flow has stopped in the system. A proof demand
error will latch when this condition exists.
Primary Pump Rotation Setting in Adjust Menu
The control rotates the pumps based on the Rotate item
in the Adjust menu. Frequency of Rotation is based on the
running time of the pumps. Rotation is done when the lead
pump is off. If the lead pump runs continuously, the rotation
is delayed for up to 12 hours. If the pump runs continuously
and rotation is required, the control shuts off the lead pump
and 1 second later the stand-by pump is turned on. This
eliminates overloading the pump electrical circuit. Upon
turning on the stand-by pump the flow proof input is checked
after the flow proof demand delay time.
Boiler Pump Operation
The control can operate individual boiler pumps when set
to Mode 2, 4 or 5. Refer to the Boiler Operation section for
more information about the mode settings.
A pre-purge operates the respective boiler pump for a period
of time before the boiler is ignited in order to purge potential
residual heat out of the boiler.
The pre-purge time is determined from the boiler mass
setting. As the boiler mass setting is increased, the boiler
pump pre-purge time is also increased. The pre-purge time
is fixed at 4 seconds whenever a DHW / Setpoint demand
is provided in order to reduce boiler pick-up times.
The control includes a boiler pump post-purge feature that
operates the respective boiler pump for a period of time
after the boiler is turned off. This feature will purge heat out
of the boiler and aid in reducing “kettling”. The amount of
time for the boiler pump post purge is adjustable between
10 seconds and 19:55 minutes. See the boiler pump purge
setting in the adjust menu.
Exercising Section I
The control will exercise the Combustion Air Damper, all
pumps, and tN4 zones (zone valves and zone pumps) for
10 seconds every three days of inactivity to prevent seizure.
To enable exercising, switch the Exercise / Off DIP to the
Exercise position.
Time Clock Section J
The control has a built-in time clock to allow the control to
operate on a schedule. A battery-less backup allows the
control to keep time for up to 4 hours without power. The
time clock supports automatic adjustment for Daylight
Saving Time (DST) once the day, month, and year are
entered. Use the Time menu to set the correct time, day,
month, and year.
Note: The Setback / Off DIP Switch must be set to Setback
before the Time menu can be accessed.
Page 18
Setting the Schedule Section K
•
••
••
•
•
•
•
•
•
To provide greater energy savings, you can operate the
control on a programmable schedule. The schedule is stored
in memory and is not affected by loss of power to the control.
If a tN4 network is detected the control can become either a
schedule member or schedule master.
Control (CTRL) Schedule (tN4 present)
The schedule only applies to the control. The control follows
its own schedule and the events are not communicated to
tN4 thermostats.
Master Schedule (tN4 present)
If the control is connected to tN4 thermostats, then the
control can operate on a master schedule. You can set up
a maximum of four master schedules on the tN4 Network.
A master schedule is available to all devices on the tN4
network. Master schedules simplify installation since one
master schedule may be used by multiple devices.
To create a master schedule:
Assign the control to be a schedule master by setting
•
the Heat Schedule item in the Schedule menu to Master
(MST) 1 to 4. After a master schedule is selected, a clock
symbol will appear in the View menu display.
Note: The 274 Setback /Off DIP Switch must be set to
Setback to access the Schedule Menu.
To follow a master schedule:
Assign the control to follow a master schedule by setting
•
the Heat Schedule in the Schedule menu to Member
(MBR) 1 to 4.
Member of
Schedule 1
Master
Schedule 1
None
Zone
Schedule
Master
Schedule 2
Members of
Schedule 2
Schedule Types
The schedule type determines when the schedule repeats
itself. This control includes three schedule types:
• 24 Hour: Repeats every 24 hours.
• 5-11: Repeats on a weekly basis. However, it breaks the
week into Saturday and Sunday followed by the weekdays.
This reduces the amount of schedule event settings.
• 7 Day: Repeats on a weekly basis and allows for separate
event times for each day.
Schedule Type
Day24 Hour5-117 day
Saturday
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Schedule Mode
The schedule mode can have either 4 or 2 events per day.
An event is a time at which the control changes the target
temperature. The event time can be set to the nearest 10
minutes. If you wish to have the thermostat skip the event,
enter “--:--“ as the time. The “--:--“ time is found between
11:50 PM and 12:00 AM. See the table, Schedule Mode,
for more details regarding types of events.
274
Zone 1
23 4 56
Schedule Mode Event24HrSatSunMonTueWeThuFri
6:00 AM6:00 AM6:00 AM6:00 AM6:00 AM6:00 AM6:00 AM6:00 AM
8:00 AM8:00 AM8:00 AM8:00 AM8:00 AM8:00 AM8:00 AM8:00 AM
When the control changes from the UnOccupied mode to
the Occupied mode, it enters into a boosting mode. In this
mode, the supply water temperature to the system is raised
above its normal values for a period of time to provide a
faster recovery from the setback temperature of the building.
The maximum length of the boost is selected using the
BOOST setting in the Adjust menu.
Typical settings for the boost function vary between 30
minutes and two hours for buildings that have a fast
responding heating system. For buildings that have a slow
responding heating system, a setting between four hours
and eight hours is typical. After a boost time is selected, the
setback timer must be adjusted to come out of setback some
time in advance of the desired occupied time. This time in
advance is normally the same as the BOOST setting.
Page 19
If the building is not up to temperature at the correct time,
the BOOST setting should be lengthened and the setback
timer should be adjusted accordingly. If the building is
up to temperature before the required time, the BOOST
setting should be shortened and the setback timer should
be adjusted accordingly. If the system is operating near
its design conditions or if the supply water temperature
is being limited by settings made in the control, the time
required to bring the building up to temperature may be
longer than expected.
tekmarNet®4 Communication Section M
tekmarNet®4 (tN4) communicates between tN4 devices
(thermostats, Reset Module and Expansion Modules). Each
tN4 device is connected to a tN4 communication bus using
two wires. Each tN4 bus adjusts a single water temperature
in the system using indoor temperature feedback. The Boiler
Control 274 allows for one tN4 bus. This allows you to control
a system with one water temperature. A system that has more
than one tN4 bus is referred to as a tN4 network.
Network
Bus 1
274
tekmarNet®4
Thermostats
Boiler Control 274
The Boiler Control 274 is the system control for a hydronic
heating system. The 274 operates up to 4 on/off boilers,
a domestic hot water tank, and responds to other heating
requirements such as pool heating and snow melting. The
274 also coordinates and optimizes the operation of all the
tN4 thermostats.
tN4 Thermostat
The tN4 thermostat operates heating, cooling, and or
ventilation equipment for a zone. Several tN4 thermostats
may work in a group when operating a cooling system. Up
to 24 tN4 devices can connect to a single tN4 bus.
Zone Load Shedding (tN4)
Zone load shedding helps protect non-condensing boilers
from sustained flue gas condensation damage. Zone load
shedding starts when the boiler supply temperature is below
the boiler minimum setting and all boilers are operating
at 100% output. Zones are shut off in order of their tN4
address.
Second stage heat zones are the first to shut off starting
with thermostat address b:24, continuing downward until
the last to shut off is b:01.
Once all second stage heat zones are shut off, first stage
zones shut off starting with highest thermostat address
b:24 and ending at the lowest b:01.
When the boiler supply temperature reaches the boiler
minimum, the first stage heating zones turn back on in
order from b:01 to b:24, and then the second stage in order
from b:01 to b:24.
Cycle Length Setting in Adjust Menu (tN4)
The control includes an adjustment for the cycle length.
The cycle length adjustment allows for synchronization of
tN4 zones. An Auto setting allows for the cycle length to
be automatically calculated to balance equipment cycling
and comfort.
In the tekmarNet®4 system, all of the tekmarNet®4
Thermostats determine the best cycle length for their
zone. The thermostats look at trying to maintain the longest
possible cycle length while keeping temperature swings to
a minimum. The Thermostats do this every cycle and send
their ideal cycle length time to the 274.
In order to operate the system as efficiently as possible,
all of the zones must operate based on the same cycle.
In order to do this, the 274 listens to all of the cycle length
requests from all of the tekmarNet®4 Thermostats. The 274
then determines the average cycle length and sends this
information to all of the tekmarNet®4 Thermostats, allowing
them to operate on the same cycle.
Indoor Temperature Feedback (tN4)
Indoor feedback applies when the 274 is connected to a
tN4 Thermostat network operating on a boiler bus. Indoor
temperature feedback fine tunes the water temperature of
the system based on the requirements of the thermostats.
Each thermostat tells the tN4 System Control the water
temperature that it requires to heat its zone.
If the zone is becoming too cool, the thermostat asks for
•
a higher water temperature.
If the zone is becoming too warm, the thermostat asks
•
for a cooler water temperature.
The 274 provides the highest water temperature required
by all of the thermostats.
The thermostat with the highest water temperature
•
requirement stays on 100% of its cycle.
The remaining thermostats stay on for a percentage of
•
their cycles.
100%
On Time
Reset Water
Temperature
85%
On Time
90%
On Time
Device Count (tN4)
The control includes a device count of all the tN4 devices
connected to the boiler bus. This item is always found in
the Miscellaneous Menu called NUM DEV. Use this to
confirm that the correct number of devices are connected
to the boiler bus.
Improper installation and operation of this control could
result in damage to the equipment and possibly even
personal injury or death. It is your responsibility to ensure
that this control is safely installed according to all applicable
codes and standards. This electronic control is not intended
for uses as a primary limit control. Other controls that are
intended and certified as safety limits must be placed into
the control circuit. Do not attempt to service the control.
Refer to qualified personnel for servicing. Opening voids
warranty and could result in damage to the equipment and
possibly even personal injury or death.
Step One — Getting Ready
Check the contents of this package. If any of the contents listed
are missing or damaged, please contact your wholesaler or
tekmar sales representative for assistance.
Type 274 includes:
One Boiler Control 274, One Outdoor Sensor 070, Two
Universal Sensors 082, One 500 Ohm resistor, Data Brochures
D 274, D 070, D 001, Application Brochure A 274.
Note: Carefully read the details of the Sequence of
Operation to ensure the proper control was chosen for
the application.
Step Two — Mounting the Base
Remove the control from its base by pressing on the release clip in the wiring chamber and sliding the control away from it.
The base is then mounted in accordance with the instructions in the Data Brochure D 001.
Step Three — Rough-in Wiring
All electrical wiring terminates in the control base wiring
chamber. The base has standard 7/8” (22 mm) knockouts,
which accept common wiring hardware and conduit fittings.
Before removing the knockouts, check the wiring diagram
and select those sections of the chamber with common
voltages. Do not allow the wiring to cross between sections
as the wires will interfere with safety dividers which should
be installed at a later time.
Power must not be applied to any of the wires during the
rough-in wiring stage.
All wires are to be stripped to a length of 3/8” (9 mm) to
•
ensure proper connection to the control.
Install the Outdoor Sensor 070 according to the installation
•
instructions in the Data Brochure D 070 and run the wiring
back to the control.
Install the Boiler Supply Sensor 082 according to the
•
installation instructions in the Data Brochure D 070 and
run the wiring back to the control.
Install the Boiler Return or DHW Sensor 082 according
•
to the installation instructions in the Data Brochure D 070
and run the wiring back to the control.
Run wires from any security system, alarm panel, or
•
telephone dialer back to the control.
Run wires from other system components (boilers, pumps,
•
flow switch, etc.) to the control.
Run wires from the 115 V (ac) power to the control. Use
•
a clean power source with a 15 A circuit to ensure proper
operation. Multi-strand 16 AWG wire is recommended for
all 115 V (ac) wiring due to its superior flexibility and ease
of installation into the terminals.
Step Four — Electrical Connections to the Control
General
The installer should test to confirm that no voltage is present at any of the wires. Push the control into the base and slide
it down until it snaps firmly into place.
Powered Input ConnectionsTerminals 19 - 25
115 V (ac) Power
Connect the 115 V (ac) power supply to the Power L and
Power N terminals (19 and 20). This connection provides
power to the microprocessor and display of the control.
To generate a Boiler Demand, a voltage between 20 V (ac)
and 260 V (ac) must be applied across the Boiler Demand
terminals (21 and 22).
2221
Boiler
Demand
DHW Demand
To generate a DHW Demand, a voltage between 20 V (ac)
and 260 V (ac) must be applied across the DHW/Setp and
Com Dem terminals (23 and 24). The Pump Sequencer
DIP Switch must be set to Off and DHW MODE must be
set to 1 through 5.
Setpoint Demand
To generate a Setpoint Demand, a voltage between 20 V
(ac) and 260 V (ac) must be applied across the DHW/Setp
and Com Dem terminals (23 and 24). The DHW MODE
must be set to OFF.
Proof Demand
To generate a Proof Demand, a voltage between 20 V (ac)
and 260 V (ac) must be applied across the Pr. Dem and
Com Dem terminals (25 and 24).
Energy Management System (EMS)
To generate an external input signal from an Energy
Management System (EMS), either a 0 to 10 V (dc) or 2
to 10 V (dc) signal must be applied to the Com – and Out
+ terminals (2 and 3).
A 0 - 20 mA signal can be converted to a 0 - 10 V (dc) signal
by installing a 500 resistor in parallel between the Com
– and Out + terminals (2 and 3).
A 4 - 20 mA signal can be converted to a 2 - 10 V (dc) signal
by installing a 500 resistor in parallel between the Com
– and Out + terminals (2 and 3).
Note: DIP Switch must be set to EMS.
20 to 260
V (ac)
20 to 260
V (ac)
20 to 260
V (ac)
20 to 260
V (ac)
0-10 V (dc)
or
2-10 V (dc)
0 - 20 mA
or
4 - 20 mA
L
N
252423
Pr.ComDHW
DemDem/Setp
L
N
252423
Pr.ComDHW
DemDem/Setp
L
N
252423
Pr.ComDHW
DemDem/Setp
N
L
32
OutCom
+
-
-
+
32
OutCom
+
OR
500
-
Resistor
-
+
Non-Powered Input Connections Terminals 1 - 6
tN4
Terminals 1 and 2 provide a tN4 connection for tN4 devices
on the tN4 bus. Connect terminals 1 (tN4) and 2 (Com) to
the corresponding terminals on the tN4 devices that are
to be connected.
tN4
Device
ComtN4
21
ComtN4
-
Note: The connection is polarity sensitive. Ensure that
terminal 1 (tN4) is connected to the tN4 terminal on the tN4
device and that terminal 2 (C) is connect to the C terminal
on the tN4 device.
Connect the two wires from the Outdoor Sensor 070
to the Com and Out (2 and 3) terminals. The outdoor
sensor is used by the control to measure the outdoor air
temperature.
Note: If an Outdoor Sensor 070 is connected to a
tekmarNet®4 thermostat in the system, it is not required
to be connected to the control.
Boiler Supply Sensor (tekmar 082)
Connect the two wires from the Boiler Supply Sensor 082
to the Com and Boil (5 and 4) terminals. The Boiler Supply
Sensor is used by the control to measure the boiler supply
water temperature.
DHW or Boiler Return Sensor (tekmar 082)
Connect the two wires from the DHW Sensor 082 to the
Com and BRet / DHW (5 and 6) terminals. The DHW
Sensor is used by the control to measure the DHW water
temperature or the DHW Exchange Supply Temperature.
OR
Connect the two wires from the Boiler Return Sensor 082
to the Com and BRet / DHW (5 and 6) terminals. The Boiler
Return Sensor is used by the control to measure the boiler
return temperature.
Outdoor
Sensor
070
Boiler Supply Sensor 082
DHW Sensor 082
OR
Boiler Return Sensor 082
-
Sup
32
OutCom
+
54
ComBoil
65
BRet/Com
DHW
Powered Output Connections Terminals 17 - 26
Primary Pump P1
The Prim P1 output on terminal (18) is a powered output.
When the relay in the control closes, 115 V (ac) is provided
to the Prim P1 terminal (18) from the Power L terminal (19).
To operate the primary pump P1, connect one side of the
primary pump circuit to terminal (18) and the second side
of the pump circuit to the neutral (Power N) side of the 115
V (ac) power supply.
Primary Pump P2
The DHW / P2 output on terminal (17) is a powered output.
When the relay in the control closes, 115 V (ac) is provided
to the DHW / P2 terminal (17) from the Power L terminal
(19). To operate the primary pump P2, connect one side
of the primary pump circuit to terminal (17) and the second
side of the pump circuit to the neutral (Power N) side of the
115 V (ac) power supply.
Primary
Pump
Backup
Primary
Pump
OR
DHW
Pump
Pump
Pump
L & N
L
N
Pump
Pump
L & N
L
N
18 19 20
Prim Power
P1 LN
1718 19 20
DHWPrim Power
P2 P1 LN
Non-Powered Output Connections Terminals 7 – 22
Wiring the T-T
(RELAY TYPE = Boiler )
Terminals 7-8, 9-10, 11-12 and 13-14 are dry contacts. No
1413121110987
RelayRelayRelayRelay
4321
power is available from these terminals. These contacts
can be used to either make or break power to a boiler or
boiler pump. The boiler must be wired to power as per the
manufacturers’ directions.
These terminals are typically connected to the boiler’s
control circuit (commonly labeled as T-T). Connect these
terminals directly to the boiler T-T connections.
Terminals 7-8, 9-10, 11-12 and 13-14 are dry contacts. No
power is available from these terminals. These contacts
can be used to turn on individual boiler pumps. Wire line
voltage to one side of the relay. The other side of the relay
goes to one side of the boiler pump and the remaining side
of the boiler pump goes to neutral.
Combustion Air / Alert Contact (C.A./Alert)
Terminals 15 and 16 are an isolated output in the control.
There is no power available on these terminals from the
control. These terminals are to be used as a switch to either
make or break power to the combustion air damper or alert
device. Since this is an isolated contact, it may switch a
voltage between 24 V (ac) and 230 V (ac).
120 V (ac)
24 to 230 V (ac)
1413121110987
RelayRelayRelayRelay
4321
Boiler
Pumps
L
N
PumpPumpPumpPump
L or R
N or C
1615
C.A./
Alert
Alert
OR
N or C
Combustion
Air
Step Five — Testing the Wiring
General
The following tests are to be performed using standard
testing practices and procedures and should only be carried
out by properly trained and experienced persons.
A good quality electrical test meter, capable of reading from
at least 0-300 V (ac), 0-30 V (dc), 0-2,000,000 Ohms, and
testing for continuity is essential to properly test the wiring
and sensors.
Testing tN4 Network Terminals 1 – 2
To test the tN4 Network, check the wires for continuity.
1. Disconnect the two wires (tN4 and Com) at one end and
connect them together.
2. Go to the other end of the wires and disconnect them.
3. Using an electrical test meter, check for continuity.
###
tN4
Device
tN4
Com
Boiler
Control
274
32
OutCom
+
-
ComtN4
21
-
Testing the EMS Output Terminals 2 – 3
If an Energy Management System is used, measure the
voltage (dc) between the Com – and the Out + terminals (2
and 3). When the EMS calls for heat, a voltage between
0 – 10 V (dc) or 2 – 10 V (dc) should be measured at the
terminals.
To test the sensors, the actual temperature at each sensor
location must be measured.
•
Use a good quality digital thermometer with a surface
Disconnect each sensor from the control.
•
Test the sensors resistance according to the instructions
•
in the sensor Data Brochure D 070.
temperature probe for ease of use and accuracy. Where
a digital thermometer is not available, strap a spare
sensor alongside the one to be tested and compare
the readings.
Testing Relay 1 – 4 Terminals 7 – 14
1. Shut off power to the control and the boiler circuit or
boiler pump circuit.
2. Remove the bottom cover from the control. Disconnect
the wiring from the Relay contacts (terminals 7 – 14).
3. Apply power to the control and press the Test button.
4. Use an electrical test meter and check for continuity
between terminals 7-8, 9-10, 11-12 and 13-14.
•
If the relay is set to boiler pump:
•
When the appropriate boiler pump symbol is displayed
in the LCD, there should be continuity.
•
When the appropriate boiler pump symbol is not displayed
in the LCD, there should be no continuity.
5. Reconnect the wires to the Relay contacts, install the
bottom cover on the control and reapply power to the
boiler circuit or boiler pump circuit.
If the relay is set to boiler ignition:
When the appropriate boiler symbol is displayed in the
•
LCD, there should be continuity.
When the appropriate boiler symbol is not displayed in
•
the LCD, there should be no continuity.
Testing C.A. / Alert Relay Terminals 15 – 16
1. Shut off power to the control and the boiler circuit or
boiler pump circuit.
2. Remove the bottom cover from the control. Disconnect the
wiring from the C.A. / Alert contact (terminals 15 – 16).
3. Apply power to the control and press the Test button.
4. Use an electrical test meter and check for continuity
between terminals 15 – 16.
If the relay is set to Combustion Air Damper:
When the Combustion Air Damper symbol is displayed
•
in the LCD, there should be continuity.
When the Combustion Air Damper symbol is not displayed
•
in the LCD, there should be no continuity.
If the relay is set to Alert:
When the Alert symbol is displayed in the LCD, there
•
should be continuity.
When the Alert symbol is not displayed in the LCD, there
•
should be no continuity.
5. Reconnect the wires to the C.A. / Alert contacts, install
the bottom cover on the control and reapply power to
the Combustion Air Damper or Alert circuit.
Testing DHW and Primary Pumps Terminals 17 - 18
1. Remove the front and bottom covers from the control.
2. Press the Test Button.
3. When the Primary Pump 1 symbol is displayed in the LCD,
use an electrical test meter to measure the (ac) voltage
between the Primary Pump 1 terminal and Neutral (18-
20). The reading should be 115 V (ac) + / – 10%.
If DHW Mode is enabled:
When the DHW Pump symbol is displayed in the LCD, use
an electrical test meter to measure the (ac) voltage between
the DHW Pump terminal and Neutral (17-20). The reading
should be 115 V (ac) + / – 10%.
If Pump Sequencer is enabled:
When the Primary Pump 2 symbol is displayed in the LCD,
use an electrical test meter to measure the (ac) voltage
between the Primary Pump 2 terminal and Neutral (17-20).
The reading should be 115 V (ac) + / – 10%.
Testing the Input Power Terminals 19 – 20
1. Remove the front and bottom cover from the control.
2. Use an electrical test meter to measure (ac) voltage
between the Input Power L and N terminals (19 and 20).
The reading should be 115 V (ac) + / – 10% and the LCD
should be lit and show some segments.
Check the circuit that supplies power to the Control.
•
Make sure exposed wires and bare terminals are not in
•
contact with other wires or grounded surfaces.
Page 25
Testing the Demands Terminals 21 – 25
1. Remove the front and bottom cover from the control.
2. Use an electrical test meter to measure (ac) voltage
between the Boiler Demand terminals (21-22) or the
DHW / Setpoint Demand terminals (23-24) or the Proof
Demand terminals (24-25).
When the demand device is on, a voltage between
•
20 and 260 V (ac) should be measured between the
appropriate demand terminals and the LCD should display
an indicator arrow pointing to Boiler Demand, DHW /
Setpoint Demand, or Proof Demand.
When the demand device is off, less than 5 V (ac) should
•
be measured between the terminals.
Control Settings
Cleaning the Control
The control’s exterior can be cleaned using a damp cloth. Moisten the cloth with water and wring out prior to wiping control.
Do not use solvents or cleaning solutions.
DIP Switch Settings
Set the DIP switch settings prior to making adjustments
to the control through the user interface. Setting the DIP
switches determines which menu items are displayed in
the user interface.
Switch Settings
When the control is locked, a small segment representing
•
a padlock is shown in the bottom right hand corner of the
display (except in View and Time Menu)
EMS
Demands
Setback
Exercise
Rotate
Off
Off
Pump Sequencer
Fixed Last
Fixed Lead
First On / Last Off
First On / First Off
EMS / Demands
The EMS / Demands DIP switch selects whether a tekmar
outdoor sensor 070 or an external 0-10 or 2-10 V (dc) input
signal is to be connected to the Com - and Out + terminals
(2 & 3).
Set the EMS / Demands DIP switch to EMS if an Energy
Management System is providing an external analog input
signal to the control.
Set the EMS / Demands DIP switch to Demands if the
control is accepting a boiler demand and using the outdoor
sensor for outdoor reset.
EMS
Demands
Setback
Exercise
Rotate
Off
Off
Pump Sequencer
Fixed Last
Fixed Lead
First On / Last Off
First On / First Off
Lock / Unlock
Use this DIP switch to lock and unlock the Access Level
of the 274 and all connected tN4 devices, including tN4
thermostats. For details, see “Access Level”.
Once locked, the access level in all devices cannot be
•
viewed or changed.
Off / Exercise
Use the Off / Exercise DIP switch to select whether or not
the control is to exercise all pumps, and hydronic zones
(zone valves and zone pumps) for 10 seconds every three
days of inactivity to prevent seizure.
EMS
Demands
Setback
Exercise
Rotate
Off
Off
Pump Sequencer
Fixed Last
Fixed Lead
First On / Last Off
First On / First Off
Setback / Off
Use the Setback / Off DIP switch to select whether or not
the control is to follow a schedule.
If the 274 is to be a schedule member or schedule master,
•
set the DIP switch to Setback to enable the Time and
Schedule menus and the Unocc items in the Adjust
menu.
If the 274 does not follow a schedule, set the DIP switch
•
to Off to disable the Time and Schedule menus and the
Unocc items in the Adjust menu.
Use the Rotate / Off DIP switch to enable the Equal Run
Time Rotation feature. This feature Changes the firing
order of the boilers in order to maintain a similar amount of
running time on each boiler. If set to Off, the firing sequence
if fixed starting with boiler 1 to boiler 4.
EMS
Demands
Setback
Exercise
Rotate
Off
Off
Pump Sequencer
Fixed Last
Fixed Lead
First On / Last Off
First On / First Off
Fixed Lead / Off
Use the Fixed Lead / Off DIP switch to exclude the first
•
boiler in the rotation sequence. This DIP is only active
when the Rotate / Off DIP is set to Rotate.
If set to Fixed Lead, the first boiler is always the first to fire.
•
Fixed Lead will only work for boilers wired to the Relay 1
•
terminals (7 and 8).
EMS
Demands
Setback
Exercise
Rotate
Off
Off
Pump Sequencer
Fixed Last
Fixed Lead
First On / Last Off
First On / First Off
Pump Sequencer / Off
Use the Pump Sequencer / Off DIP switch to activate
primary pump sequencing. DHW operation is not available
when Pump Sequencer is selected.
If set to Pump Sequencer, the control operates primary
•
pumps 1 & 2 in stand-by mode.
If set to Off, the control operates primary pump 1 and the
•
pump 2 relay is then available for a DHW pump.
EMS
Demands
Setback
Exercise
Rotate
Off
Off
Pump Sequencer
Fixed Last
Fixed Lead
First On / Last Off
First On / First Off
Fixed Last / Off
Use the Fixed Last / Off DIP switch to exclude the last boiler
in the rotation sequence. This DIP is only active when the
Rotate / Off DIP is set to Rotate.
If set to Fixed Last, the last boiler is always the last to fire.
•
Fixed Last will only work for boilers wired to the Relay 4
•
terminals (13 and 14).
EMS
Setback
Rotate
Off
Pump Sequencer
Fixed Last
Fixed Lead
First On / Last Off
First On / Last Off or First On / First Off.
The First On / Last Off or First On / First Off DIP switch
•
selects whether the first boiler is the first to fire and the
last to shut off or the first to fire and the first to shut off.
This DIP switch is only active when the Rotate / Off DIP
switch is set to Rotate and the Fixed Lead / Off DIP switch
The View menu items display the current operating
temperatures and status information of the system.
Item FieldRange
VIEW
VIEW
VIEW
VIEW
VIEW
VIEW MENU
VIEW
-76 to 149°F
(-60.0 to 65.0°C)
-22 to 266°F
(-30.0 to 130.0°C)
---, 35 to 230°F
(---, 1.5 to 110.0°C)
---, 35 to 230°F
(---, 1.5 to 110.0°C)
-22 to 266°F
(-30.0 to 130.0°C)
-22 to 266°F
(-30.0 to 130.0°C)
Access
USER
INST
ADV
USER
INST
ADV
ADV
ADV
USER
INST
ADV
ADV
Description
OUTDOOR
Current outdoor air temperature as measured by
the outdoor sensor.
Note: This item is only available when the EMS/
Demands DIP is set to Demands.
BOILER SUPPLY
Current boiler supply water temperature as
measured by the boiler sensor.
Note: This item is not available when DHW Mode is
set to 6.
BOILER TARGET SECTION C
The boiler target is the temperature the control
is currently trying to maintain at the boiler supply
sensor. “---” is displayed when no heat is required.
Note: This item is not available when DHW Mode is
set to 6.
DHW EXCHANGE TARGET SECTION C
The DHW exchange target is the temperature the
control is currently trying to maintain at the DHW
Exchange Supply Sensor. “-- - ” is displayed when
no heat is required.
Note: This item is only available when DHW Mode is
set to 5 or 6.
DHW SECTION E
Current DHW tank temperature as measured by the
DHW sensor.
Note: This item is only available if Pump
Sequencing DIP is set to Off AND either DHW
Sensor is set to On or DHW Mode is set to 6.
BOILER RETURN
Current boiler return water temperature as measured
by the boiler return sensor.
Note: This item is only available if DHW Sensor is set
to Off AND a Boiler Return sensor is present.
VIEW
BOILER ΔT
Current temperature difference between the boiler
0 to 252°F
(-18.0 to 122.5°C)
ADV
supply and boiler return sensors.
Note: This item is only available if DHW
Sensor is set to Off AND a Boiler Return sensor is
present.
VIEW
BOILER 1 RUNNING TIME SECTION C
The total running time of Boiler 1 since this item was
hr
1
0 to 9999 hours
ADV
last cleared. To clear this item, press the Up and
Down buttons simultaneously while viewing this item.
Note: This item is only available when Boiler 1 is set
to Auto.
The total running time of Boiler 2 since this item was
last cleared. To clear this item, press the Up and
Down buttons simultaneously while viewing this item.
Note: This item is only available when Boiler 2 is set
to Auto.
BOILER 3 RUNNING TIME SECTION C
The total running time of Boiler 3 since this item was
last cleared. To clear this item, press the Up and
Down buttons simultaneously while viewing this item.
Note: This item is only available when Boiler 3 is set
to Auto.
BOILER 4 RUNNING TIME SECTION C
The total running time of Boiler 4 since this item was
last cleared. To clear this item, press the Up and
Down buttons simultaneously while viewing this item.
Note: This item is only available when Boiler 4 is set
to Auto.
PRIMARY PUMP 1 RUNNING TIME SECTION H
The total running time of Pump 1 since this item was
last cleared. To clear this item, press the Up and Down
buttons simultaneously while viewing this item.
PUMP 2 RUNNING TIME SECTION H
The total running time of Pump 2 since this item was
last cleared. To clear this item, press the Up and Down
buttons simultaneously while viewing this item.
Note: This item is only available when the DIP Switch
is set to Pump Sequencer.
After the last item, the control returns to the first item in the menu.
The Adjust Menu items are the programmable settings used
to operate the mechanical equipment.
MODE SECTION C
Selects the control mode of operation.
ADJUST
Occ
ADJUST
UnOcc
ADJUST
ADJUST MENU
ADJUST
35 to 100°F
(2.0 to 38.0°C)
Default = 70°F
(21.0°C)
35 to 100°F
(2.0 to 38.0°C)
Default = 70°F
(21.0°C)
0-10, 2-10
Default = 0-10
-10 to 10°F
(-5.6 to 5.6°C)
Default = 0°F
(°C)
INST
ADV
INST
ADV
ADV
ADV
ROOM OCCUPIED SECTION B
The desired room air temperature during the
occupied period. Note: This item is only available
when DIP is set to Demands AND OUT DSGN
is set between -60 to 45°F.
ROOM UNOCCUPIED SECTION B
The desired room air temperature during the
unoccupied period. Note: This item is only
available when DIP is set to Demands AND OUT
DSGN is set between -60 to 45°F.
EMS SIGNAL SECTION G
Selects the range of the Energy Management
System input signal. Note: This item is only
available when DIP set to EMS.
OFFSET SECTION G
Selects the range of the Energy Management
System input signal. Note: This item is only
available when DIP set to EMS.
ADJUST
ADJUST
OFF, 0:20 to
8:00 hr
(5 minute incre-
ADV
ments)
Default = OFF)
Au (Auto), OFF
Default = Au
1
INST
ADV
BOOST
The maximum amount of morning boost when
changing from the unoccupied to the occupied
period. Note: This item is only available when
DIP is set to Demands AND DIP is set to
Setback.
Selects Whether Boiler 2 is operational or not.
CP1 copies the settings of boiler 1 to boiler 2.
BOILER 3 SECTION C
Selects whether Boiler 3 is operational or not.
CP1 copies the settings of boiler 1 to boiler 3.
BOILER 4 SECTION C
Selects whether Boiler 4 is operational or not.CP1
copies the settings of boiler 1 to boiler 4.
OUTDOOR DESIGN SECTION B
The design outdoor air temperature used in the
heat loss calculations for the heating system.
Typically set to the outdoor temperature of the
coldest day of the year.
TERMINAL SECTION B
The type of heating terminal units that are being used.
Note: This item is only available when the
DIP is set to Demands AND OUT DSGN is set
between -60 to 45°F.
BOILER INDOOR SECTION B
The design indoor air temperature used in the
heat loss calculation for the boiler zones. Typically
set to 70°F (21.0°C). Note: This item is only
available when the DIP is set to Demands AND
OUT DSGN is set between -60 to 45°F.
BOILER DESIGN SECTION B
The supply water temperature required for boiler
zones on the typical coldest day of the year.
Note: This item is only available when the DIP is
set to Demands AND OUT DSGN is set between
-60 to 45°F.
BOIL MINIMUM SECTION C
The minimum allowed boiler target temperature
and boiler return protection temperature. Check
the boiler manufacturer’s manual for recommend
supply water temperatures.
90 to 225°F,
ADJUST
OFF
(32.0 to
107.0°C, OFF)
Default = 200°F
ADV
BOILER MAXIMUM SECTION C
The maximum boiler target supply temperature
for heat, setpoint and DHW demands. Set
below the high limit setting on the boiler.
The temperature differential that the control is
to use to cycle the boiler On and Off (half above
and half below target).
BOILER STAGE MODE SECTION C
Selects the firing sequence of the stages when
using multi-stage boilers.
Note: Only available in Mode 3.
RELAY SECTION D
Selects the operation of the relay to be either
combustion air or alert.
PROOF DEMAND SECTION D
Selects the operation of the Proof Demand
to be either off, flow proof, or combustion air
damper.
Note: C.A. only available if RELAY is set to
DMPR.
ADJUST
Primary
ADJUST
ADJUST MENU
ADJUST
ADJUST
ADJUST
1
min
Default = 0:30
0:10 to 3:00
0:10 to 3:00
min
Default = 1:00
min
0:00 to 3:00
Default = 1:00
0:30 to 40:00
Default = Au
min
0:00 to 3:00
Default = 0:10
minutes
(pump)
minutes
(damper)
minutes
Au (Auto),
minutes
minutes
ADV
ADV
ADV
ADV
ADV
PUMP PROOF DEMAND DELAY
SECTION D
The time allowed for the control to receive a
proof demand once the primary pump turns on.
Note: Only available when PROOF DEMAND
is set to F P.
CA PROOF DEMAND DELAY SECTION D
The time allowed for the control to receive a proof
demand once the C.A. contact turns on.
Note: Only available if RELAY is set to DMPR AND
Proof Demand is set to C A.
DAMPER DELAY SECTION D
The time delay for the boiler to operate once
the combustion air damper relay closes.
Note: Only available if RELAY is set to DMPR AND
Proof Demand is set to OFF or FP.
STAGE DELAY SECTION C
The minimum delay between the operation of stages.
Note: This item is only available when at least
two boilers are set to Au.
BOILER 1 FIRE DELAY
SECTION C
Delay from turn-on of ignition until the burner
fires.
Note: This item is only available when
Boiler 1 is set to Au.
The thermal mass characteristics of the boiler.
Note: This item is only available when
SECTION C
Boiler 1 is set to Au.
min
OFF, 0:10 to
19:55 minutes
Default = 0:20
1
min
ADV
BOILER PUMP 1 PURGE SECTION H
The time the boiler pump remains on once the
boiler is turned off.
Note: This item is only available when
Boiler 1 = Au and Mode = 2, 4 or 5.
Note: The previous 2 menu items will repeat for up to four boilers that are set to Au.
CYCLE LENGTH SECTION M
AUTO, 5 to 30
minutes
Default = Auto
ADV
The cycle length to which all tN4 devices will
synchronize.
Note: This item is only available when a tN4
device is present.
OFF,
1 (parallel, no priority)
2 (parallel, priority)
3 (pri-sec, no priority)
4 (pri-sec, priority)
5 (parallel with last
boiler, priority)
6 (dedicated DHW)
ADV
DHW MODE SECTION E
This determines the operation of the primary
pump in combination with the DHW pump and
whether or not DHW priority is required.
Note: This item is only available when the Pump
Sequencing DIP is set to Off. DHW Mode 5 is
only available if Mode = 2.
Default = OFF
ADJUST
ADJUST MENU
ADJUST
Occ
ADJUST
UnOcc
Continued on next page.
OFF, ON
Default = OFF
OFF, 70 to
190°F (OFF,
21.0 to 87.5°C)
Default = 140°F
(60.0°C)
OFF, 70 to
190 °F
(OFF, 21.0 to
87.5°C)
Default = 120°F
(49.0°C)
ADV
INST
ADV
ADV
DHW SENSOR SECTION E
Selects if a DHW sensor is to be used for
DHW generation.
Note: This item is only available when the Pump
Sequencing DIP is to Off AND DHW Mode is
set to either 1, 2, 3 or 4.
DHW OCCUPIED
SECTION E
The temperature of the DHW tank during the
Wake and Occupied periods.
Note: This item is only available when the DHW
Mode is set to either 1, 2, 3, 4 or 6 AND the DHW
Sensor is set to On AND the Pump Sequencing
DIP is set to Off.
DHW UNOCCUPIED
SECTION E
The temperature of the DHW tank during the
Sleep and Unoccupied periods.
Note: This item is only available when the
DHW Mode is set to either 1, 2, 3, 4 or 6 AND
the DHW Sensor is set to On AND the Pump
Sequencing DIP is set to Off, AND the Setback
DIP = Setback.
The temperature differential (swing up and
down) of the DHW tank from the DHW setting.
Note: This item is only available when DHW
Mode is set to either 1, 2, 3, 4 or 6 AND the DHW
Sensor is set to On, AND the Pump Sequencing
DIP is set to Off.
DHW EXCHANGE OCCUPIED SECTION E
The boiler supply temperature to the DHW heat
exchanger during the Occupied and Wake periods.
Note: This item is only available when DHW
Mode is set to 1,2,3,4 or 5, AND the DHW Sensor
is set to OFF, AND the Pump Sequencing DIP
is set to OFF.
DHW EXCHANGE UNOCCUPIED SECTION E
Selects whether the control should respond
to DHW Demands during the Sleep and
Unoccupied periods.
Note: This item is only available when DHW
Mode is set to 1,2,3,4 or 5, AND the DHW Sensor
is set to OFF, AND the Pump Sequencing DIP
is set to OFF AND the Setback DIP is set to
Setback.
ADJUST
ADJUST MENU
ADJUST
ADJUST
Occ
ADJUST
UnOcc
1, 2, 3, 4
Default = 2
OFF,
1 (parallel, no priority)
2 (parallel, priority)
3 (pri-sec, no priority)
4 (pri-sec, priority)
Default = 1)
OFF, 60 to
220°F
(15.5 to
104.5°C)
Default = 180°F
(82°C)
OFF, ON
Default = OFF
ADV
ADV
ADV
ADV
DHW BOILER SECTION E
The number of boilers used for indirect DHW
generation.
Note: This item is only available when DHW
Mode is set to either 1,2,3,or 4 AND the Pump
Sequencing DIP is set to Off.
SETPOINT MODE SECTION F
Selects the Setpoint mode of operation. This
determines the operation of the primary pump
and whether or not priority is required.
Note: This item is only available when
DHW Mode is set to OFF.
SETPOINT OCCUPIED SECTION F
The minimum boiler target temperature when
a Setpoint Demand is present during the
Wake and Occupied periods.
Note: This item is only available when DHW
Mode is set to OFF.
SETPOINT UNOCCUPIED SECTION F
Selects whether the control should respond to
Setpoint demands while in unoccupied mode.
Note: This item is only available when DHW Mode
is set to OFF, and Setback DIP is set to On.
Selects whether Zone Load Shedding is active
or not.
Note: This item is only available when a tN4 device
is present and Boil Min is set between 80 to 180°F
(26.5 to 82.0°C).
PRIORITY OVERRIDE SECTION E & F
The amount of time priority is given for DHW or
Setpoint operation before space heating resumes.
Note: This item is only available when DHW
Mode is set to either 2,4,or 5, OR Setpoint mode
is set to either 2,or 4.
WWSD OCCUPIED SECTION B
The system’s warm weather shut down temperature
during the Wake and Occupied periods. The
WWSD applies to the space heating loads only.
It does not affect DHW or Setpoint heating loads.
Note: This item is only available when the DIP
is set to Demands.
WWSD UNOCCUPIED SECTION B
The system’s warm weather shut down temperature
during the Sleep and Unoccupied period.
Note: This item is only available when the
DIP is set Demands and the DIP is set to
Setback.
ADJUST MENU
ADJUST
12
Primary
ADJUST
Primary
ADJUST
12 to 180 hours,
hr
Default = 96
OFF, 0:10 to
min
19:55 minutes
Default = 0:20
OFF, 3 to 40
min
minutes
Default = 20
minutes
OFF
hours
min
ADV
ADV
ADV
ROTATE PRIMARY PUMPS SECTION H
Sets the frequency of rotation of the primary pumps.
Note: This item is only available when the DIP
is set to Pump Sequencer.
PURGE PRIMARY PUMP SECTION H
Time the primary pump remains on once the
demand is removed to purge heat from the
boiler.
BOILER ALERT
Alert signal if boiler supply does not increase
in temperature within the selected time.
Note: This item is only available when RELAY
is set to ALRT.
After the last item, the control returns to the first item in the menu.
Note: This item is only available when Daylight Savings
Time is set to Mode 1 or 2.
TIME
TIME MENU
12 hr OR 24 hr
Default = 12 hr
INST
ADV
MODESECTION J
Select whether time should be displayed using a 12
or a 24 hour clock.
After the last item, the control returns to the first item in the menu.
Schedule Menu (1 of 3)
Note: The Setback / Off switch setting must be in the Setback position in order to have access to the SCHEDULE menu.
Item FieldRange
SCHD
SCHD
SCHEDULE MENU
SCHD
NONE, CTRL,
MST1, MST2,
MST3, MST4,
MBR1, MBR2,
MBR3, MBR4
Default = NONE
24 hr,
5-11, 5-2, 7DAY
Default = 24 hr
2 (Occ, UnOcc),
4 (Wake, UnOcc,
Occ, Sleep)
Default = 4
Access
USER
INST
ADV
USER
INST
ADV
USER
INST
ADV
The Schedule menu items set the schedule type, the
number of events per day, and the event times.
Description
HEAT SCHEDULE SECTION K
If a schedule is not required, select NONE.
If the schedule is only used by this control, select CTRL.
If the schedule is shared with other tN4 devices, select
MST1 to MST4.
If the schedule is set on another tN4 device, select
MBR1 to MBR4.
Note: This item is only available if the Setback DIP is
set to On and a tN4 device is present.
SCHEDULE TYPE SECTION K
Select the type of schedule.
Note: This item is only available when the Heat
Schedule is set to MST1 through MST4 AND the
Setback DIP is set to On.
SCHEDULE MODE SECTION K
Select the number of events per day.
Note: This item is only available when the Heat
Schedule is set to CTRL, or MST1 through MST4
AND the Setback DIP is set to On.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set to On AND the Schedule Type is
set to 24 hr.
MONDAY THROUGH FRIDAY SECTION K
Select the times for the scheduled events.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set to On AND the Schedule Type is
set to 5-2 or 5-11.
SCHD
Wake UnOccSleep
AM
Wake
UnOccupied
Occupied
Sleep
SCHEDULE MENU
SCHD
Wake UnOccSleep
Wake
UnOccupied
Occupied
Sleep
SCHD
Wake UnOccSleep
Wake
UnOccupied
Occupied
Sleep
AM
AM
– –:– – to 11:50 PM
or
– –:– – to 23:50
Default = 6:00 AM
Default = 8:00 AM
Default = 6:00 PM
Default = 10:00 PM
– –:– – to 11:50 PM
or
– –:– – to 23:50
Default = 6:00 AM
Default = 8:00 AM
Default = 6:00 PM
Default = 10:00 PM
– –:– – to 11:50 PM
or
– –:– – to 23:50
Default = 6:00 AM
Default = 8:00 AM
Default = 6:00 PM
Default = 10:00 PM
USER
INST
ADV
USER
INST
ADV
USER
INST
ADV
SATURDAY AND SUNDAY SECTION K
Select the times for the scheduled events.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set to On AND the Schedule Type is
set to 5-2.
SATURDAY SECTION K
Select the times for the scheduled events.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set to On AND the Schedule Type is
set to 5-11 or 7 Day.
SUNDAY SECTION K
Select the times for the scheduled events.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set to On AND the Schedule Type is
set to 5-11 or 7 Day.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set On AND the Schedule Type is
set to 7 Day.
TUESDAY SECTION K
Select the times for the scheduled events.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set On AND the Schedule Type is
set to 7 Day.
SCHD
Wake UnOccSleep
AM
Wake
UnOccupied
Occupied
Sleep
SCHEDULE MENU
SCHD
Wake UnOccSleep
Wake
UnOccupied
Occupied
Sleep
SCHD
Wake UnOccSleep
Wake
UnOccupied
Occupied
Sleep
AM
AM
– –:– – to 11:50 PM
or
– –:– – to 23:50
Default = 6:00 AM
Default = 8:00 AM
Default = 6:00 PM
Default = 10:00 PM
– –:– – to 11:50 PM
or
– –:– – to 23:50
Default = 6:00 AM
Default = 8:00 AM
Default = 6:00 PM
Default = 10:00 PM
– –:– – to 11:50 PM
or
– –:– – to 23:50
Default = 6:00 AM
Default = 8:00 AM
Default = 6:00 PM
Default = 10:00 PM
USER
INST
ADV
USER
INST
ADV
USER
INST
ADV
WEDNESDAY SECTION K
Select the times for the scheduled events.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set On AND the Schedule Type is
set to 7 Day.
THURSDAY SECTION K
Select the times for the scheduled events.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set On AND the Schedule Type is
set to 7 Day.
FRIDAY SECTION K
Select the times for the scheduled events.
Note: This item is only available when the Heat
Schedule is set to CTRL or MST1 to MST4 AND the
Setback DIP is set On AND the Schedule Type is
set to 7 Day.
After the last item, the control returns to the first item in the menu.
The Miscellaneous menu items set display and control
options such as access level and temperature units.
Item FieldRange
MISC
MISC
MISC
MISC MENU
USER,
INST, ADV
Default = INST
°F, °C
Default = °F
1 to 24
Access
USER
INST
ADV
USER
INST
ADV
ADV
Description
ACCESS LEVEL PAGE 4
The access level of the control. The access column
shows which items are visible in each access level.
Note: This item is only available when the Lock /
Unlock DIP switch on the control is set to Unlock.
UNITS
Select Fahrenheit or Celsius as the temperature
units.
NUMBER OF DEVICESSECTION M
Number of tN4 devices connected to this tN4 bus.
DEFAULT
MISC
OFF, SEL
ADV
Default = OFF
Press and hold the up and down buttons for 1
second to display DEFAULT SEL and load the default
settings.
MISC
274, Software Version
USER
INST
ADV
TYPE
Product number of this control. Hold the Up button
to view the software version.
After the last item, the control returns to the first item in the menu.
The control has a built-in test routine that tests the main
control functions. The control continually monitors the
sensors and displays an error message whenever a fault
is found. The individual outputs and relays are tested using
a test sequence.
Test Sequence
Each step in the test sequence lasts 10 seconds.
Start the test sequence by pressing the Test button.
•
Pause the test sequence by pressing the Test button
•
again. To advance to the next step, press the Test
button again.
If the test sequence is paused for more than five minutes,
•
the control exits the entire test routine.
To advance to a particular step, repeatedly press and
•
release the Test button to display the appropriate device.
HAZARD
Access to the Test button requires the removal of the
front cover and exposes hazardous voltage while the
control is powered. Only trained, qualified and competent
personnel should operate the Test button.
Te s t
Step 1 IF the RELAY item is set to ‘Damper’ or ‘Alert’
the C.A. / Alert relay is closed.
IF the RELAY item is set to ‘Alert’, the C.A. /
Alert relay is opened after 10 seconds.
Step 2 The Primary Pump 1 relay is closed.
IF Pump Sequencer DIP = On, the Primary
Pump 1 relay is opened after 10 seconds.
IF Pump Sequencer DIP = On
Step 3 The Primary Pump 2 relay is closed.
IF Boiler 1 = Auto
(repeat for each boiler set to Auto or CP1)
Step 4 If mode indicates that a boiler pump is used,
the boiler pump is turned on a remains on.
Next, the first stage of the boiler is turned on
and remains on. If a second stage is present,
the second stage is turned on and remains
on. If a third stage is present, the third stage
is turned on and remains on. If a fourth stage
is present, the fourth stage is turned on and
remains on. After ten seconds all stages and
the boiler pump are turned off.
Press and Hold
for 1 second
Step 7 The DHW relay is closed.The C.A. / Alert relay is opened.The primary pump is turned off.The control exits the test sequence.
If a device fails to operate during the test sequence, refer
to the installation section of this brochure to check the
operation of the control. If the control works properly,
refer to any troubleshooting information supplied by the
equipment manufacturer.
Max Heat
The control has a function called Max Heat. As long as
there is a demand for heat the control operates in this mode
for up to 24 hours or until the Test button is pressed. tN4
devices operate to meet their occupied setting +5°F (3°C)
and display the MAX segment to indicate the Max Heat
mode. Use this mode to run the circulators during system
start-up to purge air from the piping.
When a boiler demand is present the control targets
•
Boiler Maximum. If Boiler Minimum = Off, the control then
targets Boiler Design. This allows the Boiler Maximum
setting to be set higher for DHW generation.
When a DHW demand is present the control targets the
•
lower of Boiler Maximum or DHW Exchange.
The Boil Maximum setting and DHW Exchange setting
•
are always available in the Adjust Menu when in Max
Heat. The Boiler Design setting is also available in the
Adjust Menu when in Max Heat and the Boiler Minimum
is set to Off.
DHW priority and WWSD are disabled.
•
To enable Max Heat:
Press and hold the Test button for more than 3 seconds
and less than 6 seconds and the test LED will begin to
flash rapidly. MAX HEAT and TEST are displayed on
screen. No outputs are turned on until there is a demand
for heat present.
Te s t
To Cancel Max Heat:
Press the Test button to cancel Max Heat manually or wait
24 hours and the control will automatically leave the Max
Heat mode.
Zone Test
In Zone Test mode, each tN4 device can be individually
turned on one at a time. The control tests each zone for up
to 5 minutes of no button activity. Use this feature to purge
air out of each zone and assist in troubleshooting. No items
are available in the user interface of the control.
1. Press and hold the Test button for more than 6 seconds.
The control displays ZONE TEST OFF and the Test LED
remains on.
Te s t
Press and Hold
for 6 seconds
2. Press the Up button to change the display to ZONE
TEST ON. After 3 seconds, the boiler and all pumps
are shut off.
3. The control operates stage one of the tN4 device with
the lowest address number. Device number one (b:01)
has the lowest address number and device 24 (b:24)
has the highest address number. All other tN4 zones
are shut off.
Error Messages (1 of 3)
Error MessageDescription
VIEW
VIEW
VIEW
VIEW
VIEW
CONTROL ERROR ADJUST
The control failed to read the Adjust Menu settings, and reloaded the factory default settings.
Operation stops until you check all the Adjust Menu settings.
Note: To clear the error, the access level must be set to Advanced and the settings in the
Adjust menu must be checked.
CONTROL ERROR TIME
The control failed to read the Time Menu settings, and reloaded the factory default settings.
Operation continues normally.
Note: To clear the error, the access level must be set to Advanced and the settings in the
Time menu must be checked.
CONTROL ERROR SCHEDULE
The control failed to read the Schedule Menu settings, and reloaded the factory default
settings. Operation continues normally.
Note: To clear the error, the access level must be set to Advanced and the settings in the
Schedule menu must be checked.
CONTROL ERROR MISCELLANEOUS
The control failed to read the Miscellaneous Menu settings, and reloaded the factory default
settings. Operation continues normally.
Note: To clear the error, the access level must be set to Advanced and the settings in the
Miscellaneous menu must be checked.
TN4 BUS ERROR
Communication has been lost on the Boiler Bus due to a short or open circuit. Check the
tN4, C and R wires for each tN4 device. Check the polarity of the C and R wires. Check for
loose or broken wires. Press and hold the up and down arrow buttons together for 5 seconds
to manually clear error.
4. Pressing the Up button will turn off stage 1, and turn on
stage 2 of the same device (if that device has a second
stage) or turn on stage 1 of the device with the next lowest
address. The Down button can be pressed to move to
a device with a lower address number. The second
stage of a two stage zone is indicated with a small 2 in
the display.
5. The Up and Down buttons can then be used to move
through the devices and the heating stages of each
device on the boiler bus.
To cancel the Zone Test press the Test button. Once the
Zone Test ends or is cancelled, the control resumes normal
operation.
VIEW
DEVICE LOST
Communication is lost to a tN4 device on the Boiler Bus. The number shown is the address
of the lost device. The LCD on the lost device displays Bus Boil OPn. Ensure that there is
power to the lost device. Trace the wires from the control to the lost device looking for loose
or damaged wires. The error message self clears when the error condition is corrected.
Note: If you deliberately remove a tN4 device, hold the Up and Down buttons to clear the error.
VIEW
MASTER DEVICE ERROR
More than one tN4 System control has been detected on the tN4 bus. This generally indicates
that two tN4 buses are wired together. Check the tN4 bus wiring. The error message clears
once the error condition is corrected.
More than one tN4 device has been assigned the same master number.
VIEW
VIEW
VIEW
VIEW
VIEW
BOILER SUPPLY SENSOR SHORT CIRCUIT
Due to a short circuit, the control failed to read the boiler supply sensor. When there is a call
for heat, the control no longer controls the boiler(s). Instead, the control provides a boiler
enable to the boiler’s aquastat or boiler control until the sensor is repaired. The control will
not operate the boiler contact if the Boil Minimum setting is less than 100°F (38.0°C). Locate
and repair the problem as described in the Data Brochure D 070. The error message self
clears once the error condition is corrected.
BOILER SUPPLY SENSOR OPEN CIRCUIT
Due to an open circuit, the control failed to read the boiler supply sensor. The control no longer
controls the boiler. Instead, the control provides a boiler enable to the boiler’s aquastat or boiler
control until the sensor is repaired. The control will not operate the boiler contact if the Boil
Minimum setting is less than 100°F (38.0°C). Locate and repair the problem as described in
the Data Brochure D 070. The error message self clears once the error condition is corrected
Note: If you deliberately remove the boiler supply sensor, power down for 10 seconds then
restart the control.
OUTDOOR SENSOR SHORT CIRCUIT
Due to a short circuit, the control failed to read the outdoor sensor. As a result, the control
assumes an outdoor temperature of 32°F (0.0°C) and continues operation. Locate and repair
the problem as described in the Data Brochure D 070. The error message self clears once
the error condition is corrected.
OUTDOOR SENSOR OPEN CIRCUIT
Due to an open circuit, the control failed to read the outdoor sensor. As a result, the control
assumes an outdoor temperature of 32°F (0.0°C) and continues operation. Locate and repair
the problem as described in the Data Brochure D 070. The error message self clears once
the error condition is corrected.
DEVICE SCHEDULE ERROR
The selected system schedule is no longer available. Either the system schedule master is
no longer connected to the network or the system schedule number has been changed on
the schedule master. The error message self clears once the error condition is corrected.
VIEW
DEVICE ERROR AT ADDRESS #:##
#.## is the address of the device with the error. The bus number displays before the colon,
and the device number display after. Go to the device with the address displayed.
Possible Addresses:
b:01 to b:24 - Device Error on Boiler Bus
VIEW
DHW SHORT CIRCUIT
Due to a short circuit, the control failed to read the DHW sensor. As a result, the control no
longer heats the DHW tank. Locate and repair the problem as described in the Data Brochure
D 070. DHW tank heating will resume once the sensor problem is corrected. The error message
self clears once the error condition is corrected.
VIEW
DHW OPEN CIRCUIT
Due to an open circuit, the control failed to read the DHW sensor. As a result, the control no
longer heats the DHW tank. Locate and repair the problem as described in the Data Brochure
D 070. DHW tank heating will resume once the sensor problem is corrected. The error message
self clears once the error condition is corrected.
The primary pump P1 has failed. The Prim P1 relay closed, but a flow proof demand was not
detected before the proof demand delay time elapsed.
VIEW
PRIMARY PUMP P2 FAILURE
The primary pump P2 has failed. The Prim P2 relay closed, but a flow proof demand was not
detected before the proof demand delay time elapsed.
VIEW
PUMP PROOF DEMAND ERROR
The primary pump has been turned off, but the pump proof demand remains after 4
minutes.
VIEW
VIEW
VIEW
VIEW
VIEW
COMBUSTION AIR DAMPER FAILURE
The combustion air damper has failed. The C.A. relay closed, but the control did not detect
a damper proof demand before the proof demand delay time elapsed.
DAMPER PROOF DEMAND ERROR
The combustion air damper has been turned off, but the damper proof demand remains after
4 minutes.
BOILER RETURN SENSOR SHORT CIRCUIT
Due to an short circuit, the control failed to read the boiler return sensor. The control will
continue to operate normally. Locate and repair the problem as described in the Data Brochure
D 070. The error message self clears once the error condition is corrected.
BOILER RETURN SENSOR OPEN CIRCUIT
Due to an open circuit, the control failed to read the boiler return sensor. The control will
continue to operate normally. Locate and repair the problem as described in the Data Brochure
D 070. The error message self clears once the error condition is corrected.
BOILER ALARM ERROR
The boiler supply temperature did not increase within the boiler alarm time. To reset the alarm,
press and hold the up and down buttons for 5 seconds while viewing this error message.
VIEW
DHW ERROR
A DHW sensor and a DHW demand have been applied at the same time. The DHW tank
will not be heated until the DHW Demand signal is removed. The error message self clears
once the condition is corrected.
Boiler Control 274 One tN4, Four Stage Boiler & DHW / Setpoint
Literature — 274_D, 274_A, D 001, D 070
Control — Microprocessor control; This is not a safety (limit) control— Enclosure A, blue modified PVC plastic
Dimensions — 6-5/8” H x 7-9/16” W x 2-13/16” D (170 x 193 x 72 mm)
Approvals — Certified to CSA C22.2 Nº 24-93
Ambient conditions — Indoor use only, 32 to 122°F (0 to 50°C), < 90% RH non-condensing
Power supply — 115 V (ac) ±10% 50/60 Hz 7 VA, 1150 VA max
Relays — 230 V (ac) 5 A 1/3 hp
Demands — 20 to 260 V (ac) 2 VA
Sensors — NTC thermistor, 10 kΩ @ 77°F (25°C ±0.2°C) ß=3892
included: — Outdoor Sensor 070 and 2 of Universal Sensor 082
Limited Warranty and Product Return Procedure
Limited Warranty The liability of tekmar under this warranty is lim-
ited. The Purchaser, by taking receipt of any tekmar product (“Product”), acknowledges the terms of the Limited Warranty in effect at
the time of such Product sale and acknowledges that it has read
and understands same.
The tekmar Limited Warranty to the Purchaser on the Products sold
hereunder is a manufacturer’s pass-through warranty which the
Purchaser is authorized to pass through to its customers. Under
the Limited Warranty, each tekmar Product is warranted against
defects in workmanship and materials if the Product is installed and
used in compliance with tekmar’s instructions, ordinary wear and
tear excepted. The pass-through warranty period is for a period of
twenty-four (24) months from the production date if the Product is
not installed during that period, or twelve (12) months from the documented date of installation if installed within twenty-four (24) months
from the production date.
The liability of tekmar under the Limited Warranty shall be limited to, at
tekmar’s sole discretion: the cost of par ts and labor provided by tekmar
to repair defects in materials and/or workmanship of the defective product; or to the exchange of the defective product for a warranty replacement product; or to the granting of credit limited to the original c ost of the
defective product, and such repair, exchange or credit shall be the sole
remedy available from tekmar, and, without limiting the foregoing in any
way, tekmar is not responsible, in contract, tort or strict product liability, for any other losses, costs, expenses, inconveniences, or damages,
whether direct, indirect, special, secondary, incidental or consequential,
arising from ownership or use of the product, or from defects in workmanship or materials, including any liability for fundamental breach of
contract.
The pass-through Limited Warranty applies only to those defective Products returned to tekmar during the warranty period. This Limited Warranty does not cover the cost of the parts or labor to remove or transport
the defective Product, or to reinstall the repaired or replacement Product,
all such costs and expenses being subject to Purchaser’s agreement and
warranty with its customers.
Any representations or warranties about the Products made by Purchaser
to its customers which are different from or in excess of the tekmar Limited Warranty are the Purchaser’s sole responsibility and obligation. Purchaser shall indemnify and hold tekmar harmless from and against any
and all claims, liabilities and damages of any kind or nature which arise
out of or are related to any such representations or warranties by Purchaser to its customers.
The pass-through Limited Warranty does not apply if the returned Product has been damaged by negligence by persons other than tekmar,
accident, fire, Act of God, abuse or misuse; or has been damaged by
modifications, alterations or attachments made subsequent to purchase
which have not been authorized by tekmar; or if the Product was not
installed in compliance with tekmar’s instructions and/or the local codes
and ordinances; or if due to defective installation of the Product; or if the
Product was not used in compliance with tekmar’s instructions.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS
OR IMPLIED, WHICH THE GOVERNING LAW ALLOWS PARTIES TO
CONTRACTUALLY EXCLUDE, INCLUDING, WITHOUT LIMITATION,
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE, DURABILITY OR DESCRIPTION OF THE
PRODUCT, ITS NON-INFRINGEMENT OF ANY RELEVANT PATENTS
OR TRADEMARKS, AND ITS COMPLIANCE WITH OR NON-VIOLATION OF ANY APPLICABLE ENVIRONMENTAL, HEALTH OR SAFETY
LEGISLATION; THE TERM OF ANY OTHER WARRANTY NOT HEREBY
CONTRACTUALLY EXCLUDED IS LIMITED SUCH THAT IT SHALL NOT
EX TEND BEYON D TWE NTY-F OUR (24) MON THS FRO M TH E PROD UCTION DATE, TO THE E XTENT THAT SUCH LIMITATION IS ALLOWED BY
THE GOVERNING LAW.
Product Warranty Return Procedure All Products that are believed to
have defects in workmanship or materials must be returned, together
with a written description of the defect, to the tekmar Representative
assigned to the territory in which such Product is located. If tekmar
receives an inquiry from someone other than a tekmar Representative,
including an inquiry from Purchaser (if not a tekmar Representative) or
Purchaser’s customers, regarding a potential warranty claim, tekmar’s
sole obligation shall be to provide the address and other contact information regarding the appropriate Representative.
tekmar Control Systems Ltd., A Watts Water Technologies Company.