Page 1
- Data Brochure
Steam Control 279
D 279
05/10
The tekmar Steam Control 279 can operate a single on-off steam boiler or an on-off steam valve using outdoor reset. The
control determines the on time of the boiler or valve based on the measured outdoor temperature and settings entered by
the installer. A large LCD displays the current status and operating temperatures.
Additional functions include:
•
CSA approved for use in USA and Canada
•
Outdoor Reset
•
Manual Override
•
Includes Outdoor Sensor
•
Includes Condensate Sensor
•
Large LCD Display
Optional Indoor Sensors
•
•
DHW Tankless Coil Operation
•
Warm Weather Shut Down
•
Built-in Programmable Timer
•
24 Hour, 5-1-1, 7 Day Schedule
•
Two or Four Schedule Events Per Day
•
Two Alert Level Relays
Input
115 V (ac)
Power Supply
Menu Item
Steam Control 279
One Stage
2N3
4
1
Power
Alert 1 Boiler
L
STATUS
Establishing Steam
Heat Cycle
Lockout Differential
DHW Tankless Coil Heating
6785
Alert 2
LowHigh
Average
Indoor S2
Indoor S1
Installer
User
Condensate Sensor
DHW Tankless Coil Sensor
Setback
Off
Test
off
red
red
For manual operation,
press and hold Test
button for 3 seconds.
Com
Sen
Meets Class B:
Canadian ICES
FCC Part 15
16
15
14
Out
Cdn
Sen
Sen
Made in Canada By
tekmar Control Systems Ltd.
tektra 969-04
Power 115 V ±10% 50/60 Hz 3.5 VA
Relays 230 V (ac) 5 A 1/3 hp, pilot duty 240 VA
Signal wiring must be rated at least 300 V.
Do not apply power
12
11
10
Com
Sen
9
Com
Sen
DHW
Sen
13
Indr
Indr
S2
S1
not testing
testing
testing paused
Date Code
H2046A
Input
Outdoor
Sensor
Included
Output
High Priority
Alert
Output
Low Priority
Alert
OR
Output
Boiler or On/Off
Steam Valve
M
Input
Universal Sensor
Optional
Input
Indoor Sensor
Optional
Input
Indoor Sensor
Optional
Input
Universal Sensor
Included
1 of 24 © 2010 D 279 - 05/10
Page 2
How to Use the Data Brochure
This brochure is organized into four main sections. They
are: 1) Sequence of Operation, 2) Installation, 3) Control
Settings, and 4) Testing and Troubleshooting. The Sequence
of Operation section has fourteen sub-sections. We
recommend reading ‘Section A: General’ of the Sequence
of Operation, as this contains important information on the
overall operation of the control. Then read the sub sections
that apply to your installation.
Table of Contents
User Interface ............................................................... 2
Display and Symbol Description ...................................3
Definitions .....................................................................4
Sequence of Operation .................................................4
General ................................................................. 4
Establishing Steam ...............................................4
Heating Cycle .......................................................6
Lockout Differential ...............................................7
Optional Indoor Sensors .......................................8
Built-in Timer ........................................................8
Programmable Schedule ......................................8
Warm Weather Shut Down ...................................8
Optimum Start ......................................................9
Boost ....................................................................9
Limited Occupied ..................................................9
The Control Settings section (starting at Switch Settings) 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.
Alert Relay Operation ...........................................9
Domestic Hot Water Tankless Coil ..................... 10
Installation .................................................................. 10
Cleaning the Control ................................................... 14
Switch Settings ........................................................... 15
Display Menus ............................................................ 16
View Menu .......................................................... 16
Adjust Menu ........................................................ 17
Time Menu .......................................................... 19
Schedule Menu ................................................... 20
Testing the Control ......................................................20
Troubleshooting .......................................................... 21
Error Messages ..........................................................22
Technical Data ............................................................ 24
Limited Warranty ........................................................24
User Interface
The control uses a Liquid Crystal Display (LCD) as the
method of supplying information. Use the LCD in order to
setup and monitor the operation of the system. The control
has four push buttons (Menu, Item, , ) for selecting and
adjusting settings. As the control is programmed, record
the 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
four menus: View, Adjust, Time, and Schedule. These
menus are listed on the top of the display (Menu Field).
To select a menu, use the Menu button. By pressing and
releasing the Menu button, the display will advance to the
next available menu. Once a menu is selected, there will be
a group of items that can be viewed within the menu.
Note: The TIME and SCHEDULE menus are not available
when Setback is turned off.
Menu Item
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.
Menu Item
Adjust
To make an adjustment to a setting in the control, begin
by selecting the appropriate 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.
© 2010 D 279 - 05/10 2 of 24
Menu Item
Page 3
Display
°°F°
Menu Field
Displays the
current menu
Item Field
Displays the current
item selected.
Buttons
Selects Menus, Items
and adjusts settings
Symbol Description
Number Field
Displays the current value
of the selected item
Menu Item
Status Field
Displays the current status of the
control’s inputs, outputs and operation
STATUS
Establishing Steam
Heat Cycle
Lockout Differential
DHW Tankless Coil Heating
C
POINTER
Displays the control operation as
indicated by the text.
°F, °C
Units of measurement.
OCCUPIED SCHEDULE
Displays when the control is in the
Occupied event period.
UNOCCUPIED SCHEDULE
Displays when the control is in the
Unoccupied event period.
BURNER
Displays when the boiler contact is
turned on.
WARNING 1 2
Displays when an error exists or
when a limit has been reached. A
1 indicates a high level alert, a 2
indicates a low level alert.
USER ACCESS LEVEL
Displays when the Installer/User
Switch Setting is set to the User
access level.
STEAM ESTABLISHED
Displays once the condensate sensor
reaches a temperature sufficient for
steam to reach the furthest radiator.
BOOST
Displays while the boost feature
extends the boiler on time to allow
recovery after night setback.
OPTIMUM START
Displays while the Optimum Start
feature extends the boiler on time to
allow recovery after night setback.
WWSD
Displays while the control is in Warm
Weather Shut Down.
3 of 24 © 2010 D 279 - 05/10
Page 4
STATUS
Establishing Steam
Defi nitions
The following defined terms and symbols are used throughout this manual to bring attention to the presence of hazards of
various risk levels, or to important information concerning the life of the product.
Caution: Refer to accompanying documents.
Sequence of Operation
General Section A
Powering up the control
When the control is powered on, all segments in the LCD
are turned on for 2 seconds. Next, the control displays the
control type number in the LCD for 2 seconds. Next, the
software version is displayed for 2 seconds. Last, the control
enters into the normal operating mode.
Boiler Contact Operation
In single on-off steam boiler applications, the control uses
the boiler contact to connect to the thermostat terminals
(T-T) on the boiler. The pressure control and all other safety
devices and circuits must continue to be wired in series to
the burner circuit. The boiler contact on the control is used
to turn on or off the steam boiler burner.
In steam valve applications, the boiler contact on the control
is used to power the valve motor to open the valve. When
power is removed, the valve must close.
Status
The control has a status field on the right hand side of the
control. A pointer is shown in the status field once the boiler
contact is turned on. The pointer indicates at which point
of the steam heating system cycle the control is currently
operating at.
The steps are as follows:
Establishing Steam
•
Heat Cycle
•
Lockout Differential
•
DHW Tankless Coil Heating
•
STATUS
Establishing Steam
Heat Cycle
Lockout Differential
DHW Tankless Coil Heating
Each of these steps are described in detail in the following
sections.
Establishing Steam Section B
In steam heating systems, there is a time delay between
when the steam boiler or steam valve is turned on and
when the steam finally reaches the furthest radiator in the
system. It is important for the control to determine how
long this time delay is in order to ensure proper heating in
all rooms. When heat is required, the control activates the
boiler relay but does not consider the heating cycle to start
until steam has been established at the furthest radiator.
While the control is waiting to establish steam, the Status
field will have a pointer indicating Establishing Steam.
The control can use one of two methods to determine the
time to establish steam.
© 2010 D 279 - 05/10 4 of 24
Condensate Return Sensor
The Universal Sensor 071 included with the control can be
used to measure the temperature of the condensate return
pipe. In a one pipe system, it is recommended to install the
sensor on the bottom of the pipe just before it enters the last
radiator. In a two pipe system, it is recommended to install
the Condensate Sensor on the bottom of the condensate
return pipe of the radiator furthest from the boiler. In cases
where access to the furthest radiator is not possible, an
alternative is to locate the sensor on the bottom of the
condensate return pipe in the mechanical room. Once the
condensate sensor is installed, ensure the Condensate
Sensor/Off Switch Setting to Condensate Sensor. The
measured condensate return temperature reading is visible
in the View menu.
Page 5
The Adjust menu includes a Steam Established setting that
Establishing Steam
(warm-up period)
Establishing Steam
(warm-up period)
delays the start of the heating cycle until the condensate
sensor has reached a set temperature.
One method to set the Steam Established setting requires
two people with two-way radios. One person is at the
control location; the other person is at the furthest radiator
One Pipe System:
Last Radiator
location. The steam system can be manually started using
the Max Heat feature. Once the furthest radiator starts
to get steam, exit the Max Heat feature and view the
Condensate temperature in the View menu. The measured
condensate return temperature can be entered as the
Steam Established setting.
Most Distant Radiator
Two Pipe System:
Main
Air Vent
OK
Condensate Return
Sensor Location
Off
Boiler
Operation
220°F
210°F 200°F 190°F 180°F 170°F 160°F -
Condensate Return
Temperature
150°F 140°F -
Best
-
(warm-up period)
Establishing Steam
on
Supply Main
15 minutes
on time
est.
Steam established
temperature setting
Thermostatic
Radiator
Vent
Return
Air Vent
Steam established - start cycle
Boiler OffBoiler On
60 minute cycle 60 minute cycle
off
Boiler On
15 minutes
on time
(warm-up period)
Establishing Steam
est.
on
Tra p
Best
Supply
Air Vent
Float &
Thermostatic
Tra p
Condensate Return
Sensor Location
Boiler Off
Steam established - start cycle
45 minutes off time45 minutes off time
off
25% on time with Condensate Return Sensor and ‘Steam Established’ set to 170°F
OK
Minimum On Time
In cases where a condensate return sensor cannot be
installed, a Minimum On Time can be set to account for the
establishing steam time period. Setting a Minimum On Time
for a steam system can be problematic because a system
takes more time to reach operating temperature from a cold
start than when it is hot from a previous cycle.
5 of 24 © 2010 D 279 - 05/10
To set the Minimum On Time, manually start the steam
system using the Max Heat feature and at the same time,
start a stopwatch timer. Measure the amount of time required
for steam to reach the furthest radiator. Then, exit the Max
Heat feature and enter the recorded time as the Minimum
On Time setting.
Page 6
Heating Cycle - Heating Curve Section C
Boiler Cycled
On/Off
Boiler On 100% of Heating Cycle
C
B
75%
65%
42%
Room @ 70°F
Room @ 55°F
Room @ 75°F
-
Boiler On 100% of Heating Cycle
-
-
-
-
-
-
-
-
-
0 (°F)102030405060
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Outdoor reset is a method of operating a heating system
based on the fact that the rate at which a building loses
heat to the outdoor environment is mostly dependent on
the surrounding outdoor air temperature. As the outdoor
temperature gets colder, the heat loss of the building
increases at a proportional rate. This relationship between
heat loss and colder outdoor temperatures is called a
heating curve.
Outdoor = 50°F
Outdoor = 30°F
Outdoor = 10°F
A = Indoor Design
B = Outdoor Design
C = Boiler Design %
A
70
80
C
Boiler Cycled
On/Off
B
Outdoor Air Temperature
Percent On Time Per Heating Cycle
Heat Load = 20%
Boiler On Time = 12 min
60 min
Heat Load = 60%
Boiler On Time = 36 min
60 min
Heat Load = 100%
Boiler On Time = 60 min
60 min
In order to calibrate the control to the heat loss rate of a
particular building, the installer is required to enter the
following heating curve settings:
Indoor Design
The Indoor Design is the starting point of the heating curve.
When the measured outdoor air temperature matches the
Indoor Design setting, the control calculates a 0% on time
is required for heating the building. The factory default is
to start the heating curve at 70°F (21°C).
Outdoor Design
The Outdoor Design is the end point of the heating curve.
When the measured outdoor air temperature matches
the Outdoor Design setting, the control calculates the
boiler on time to be at the Boiler Design % setting. The
Outdoor Design should be set to the average coldest annual
temperature recorded in the building area.
Boiler Design %
The Boiler Design % is the percent output capacity of the
boiler or steam system required to heat the building when
the measured outdoor air temperature matches the Outdoor
Design setting. The factory default is 100%. If the building
envelope has been upgraded to improve the building
insulation, the existing steam boiler or steam system may be
oversized for the building. In these cases, the Boiler Design
% can be reduced to fine tune the heating curve.
Room (Occupied and Unoccupied)
The Room setting is the desired temperature of the building.
When a setback schedule is selected, there is a Room
Occupied temperature setting and a Room Unoccupied
temperature setting. When the setback schedule is turned
off, only the Room setting is available.
When an indoor sensor(s) is not connected to the control,
the Room setting operates as a parallel shift of the heating
curve. This allows fine tuning of the heating system. If the
Room setting is set above the Indoor Design setting, the
entire heating curve is shifted higher, resulting in longer
percent on times being calculated. Similarly, if the Room
setting is set below the Indoor Design setting, the entire
heating curve is shifted lower, resulting in shorter percent
on times being calculated.
-
100%
-
90%
-
75%
65%
42%
Room @ 75°F
Room @ 70°F
Room @ 55°F
7080
Outdoor Air Temperature
2030405060
-
-
-
-
-
-
-
0 (°F)10
80%
70%
60%
50%
40%
30%
20%
10%
0%
Percent On Time Per Heating Cycle
When an indoor sensor(s) is connected to the control, the
Room setting becomes a Room Target temperature. The
control measures the current air temperature in the room
using the indoor sensors. The control then automatically
shifts the heating curve so that the measured room
temperature reaches the Room Target temperature.
© 2010 D 279 - 05/10 6 of 24
Page 7
Heating Cycle - Cycle Length Section D
30 minutes
on time
30 minutes
off time
30 minutes
on time
30 minutes
off time
15 minutes
on time
15 minutes
off time
15 minutes
on time
15 minutes
off time
15 minutes
on time
15 minutes
off time
15 minutes
on time
15 minutes
off time
Establishing Steam
(warm-up period)
Lockout Period
Establishing Steam
(warm-up period)
Lockout Period
The Adjust menu includes a setting called Cycle that
determines how often the heating system will run. During
each heating cycle the boiler is turned on once, and the
boiler is turned off once. Each building has a natural heat up
and a cool off rate. This is determined by many factors such
as the size and length of runs in the steam heating system,
the size and mass of the radiators, and the heat loss of the
building. The factory default is 60 minutes. When using
optional Indoor Sensors, an automatic setting is available
that allows the control to learn the natural temperature
swing of the building. If the optional Indoor Sensors are
not used, then the only method of adjustment is trial and
error by the installer.
50% On Time With a 30 Minute Heating Cycle
Off
Boiler
Operation
Boiler On
15 minutes
on time
30 minute cycle
Boiler Off
15 minutes
off time
On Off On Off
15 minutes
on time
30 minute cycle 30 minute cycle 30 minute cycle
15 minutes
off time
50% On Time With a 60 Minute Heating Cycle
Off On
Boiler
Operation
Boiler On
30 minutes
on time
Boiler Off
30 minutes
off time
60 minute cycle
The control is designed to operate on/off steam boilers or
steam valves. These systems can only produce heat at
a fixed rate (on = 100%, off = 0%). In order to match the
heat loss of the building, the steam heating system must
be cycled on and off. To determine the boiler on time, the
control uses the percent on time required by the heating
curve and multiplies this by the heating cycle time. While
operating in the heating cycle, the Status field will have a
pointer indicating Heat Cycle.
Example:
When the outdoor temperature is 32°F (0°C), the
heating curve may determine a 50% on time is required. If the
heating cycle is 60 minutes, then the boiler on time is: Boiler On
Time Per Heating Cycle = 0.5 x 60 minutes = 30 minutes.
On Off
15 minutes
on time
On Off
15 minutes
off time
30 minutes
on time
15 minutes
60 minute cycle
on time
30 minutes
15 minutes
off time
off time
On
Lockout Differential Section E
The Adjust menu includes a setting called Lockout Differential.
When a condensate return sensor is present, a lockout
differential can be set to ensure that any remaining steam
in the system condenses and the condensate has time to
return to the boiler. This increases the efficiency of the system
by removing the latent heat of the steam remaining after
the burner is shut down, and lengthening the cycle so that
remaining heat is allowed to radiate into the building.
The lockout differential is the number of degrees the
condensate return sensor temperature must fall below the
steam established setting before the control can operate
Boiler OffBoiler On Boiler Off
Steam established - start cycle
15 minutes
on time
Boiler
Operation
220°F 210°F -
7 of 24 © 2010 D 279 - 05/10
200°F 190°F 180°F 170°F 160°F 150°F 140°F -
Condensate
Return Temperature
45 minutes off time 45 minutes off time
60 minute cycle 60 minute cycle
off
30°F Lockout
Differential Setting
Steam established
temperature setting
the heating system for the next cycle. During the lockout
differential, the heating system is held off, and the Status
field will have a pointer indicating Lockout Differential. The
factory default is a 25°F lockout differential.
There is no exact method to set the Lockout Differential for
a particular building; it is a process of trial and error. If the
building tends to over heat, the lockout differential should
be increased to allow the steam system to cool down further
before starting the next cycle. If the building tends to under
heat, the lockout differential should be decreased to allow
the next heating cycle to start sooner.
Boiler On
Steam established - start cycle
15 minutes
on time
off
Lockout Period
(warm-up period)
Establishing Steam
Steam Established
on on
Lockout Period
(warm-up period)
Establishing Steam
Page 8
Optional Indoor Sensors Section F
Multiple indoor sensors can be added to improve the
temperature accuracy within the building. Available indoor
sensors include the 076, 077 and 084.
Indoor Sensors 084, 077 and 076
The control allows two indoor sensors to be directly
connected to the control. Once an indoor sensor is
connected to the indoor sensor S1 input, the Indoor S1/Off
switch setting must be set to S1. Likewise, once an indoor
sensor is connected is connected to the S2 input, the Indoor
S2/Off switch setting must be set to S2.
When indoor sensor 1 is present, the Room 1 temperature
is visible in the View menu. Likewise, when indoor sensor
2 is present, the Room 2 temperature is visible in the View
menu. Also shown in the View menu is the current Room
Target temperature. The room target can be changed by
adjusting the Room Occupied or Room Unoccupied setting
in the Adjust menu.
Should additional indoor sensors be desired, a square
number (4, 9, 16, etc.) of sensors can be wired in seriesparallel to a single indoor sensor input.
To Indoor Sensor Input
Series - Parallel
Wiring
When using two indoor sensor inputs, the control can
operate either based upon an average of the two temperature
measurements or the control can operate on the lowest of
the two temperature measurements.
Temperature Averaging
To operate the steam system based upon the average of
the two indoor sensor temperature measurements, set the
Average/Off switch setting to Average.
Lowest of Two Temperatures
To operate the steam system based upon the lowest of
the two indoor sensor temperature measurements, set the
Average/Off switch setting to Off.
Built-in Timer Section G
The control includes a built-in time clock that is turned on once the Setback/Off switch setting is set to Setback. The time
is set in the Time menu. The clock can be set to use either 12 or 24 hour time.
Programmable Schedule Section H
The control includes a programmable schedule that is
turned on once the Setback/Off switch setting is set to
Setback. The programmable schedule is set in the Schedule
menu. The schedule can be repeated on a 24 hour, 5-1-1,
or 7 day schedule. Each schedule allows a time to be set
for the Occupied event and another time to be set for the
Unoccupied event. Should it be desired to skip an Occupied
or Unoccupied event, set the event time to --:--, which can be
found between 11:50 PM (23:50) and 12:00 AM (0:00).
Warm Weather Shut Down Section I
The control includes a Warm Weather Shut Down (WWSD)
setting in the Adjust menu. When the Setback/Off switch
setting is set to Setback, the control includes WWSD Occupied
and WWSD Unoccupied settings.
Once the measured outdoor air temperature exceeds the
WWSD setting, the steam system is automatically shut down.
Once the measured outdoor air temperature falls below the
WWSD, the control is able to start a new heating cycle.
© 2010 D 279 - 05/10 8 of 24
Page 9
Optimum Start Section J
The control includes an optimum start feature that is available
in the Adjust menu when indoor sensors are installed and
the Setback/Off switch setting is set to Setback. The
optimum start can be set to either on or off.
When a programmable schedule is used to lower the
building temperature at night, there is a time delay to
increase the building temperature from the Unoccupied to
the Occupied temperature. When optimum start is turned
on, the control uses the indoor sensor to learn the heat up
rate of the building. The control can then accurately predict
when the control should increase the heating cycle on time
Room
Tem p.
Optimum Start
10P.M. 5A.M. 8A.M.
Setback
Period
Optimum
Start
Recovery Period
Occ
70°F (21°C)
UnOcc
65°F (18°C)
so that the building reaches the Occupied temperature at
the scheduled time. Optimum Start is shown on the display
while optimum start is in effect.
Boost Section K
The control includes a boost feature that is available in the
Adjust menu when indoor sensors are not installed and the
Setback/Off switch setting is set to Setback.
When a programmable schedule is used to lower the
between Occupied and Unoccupied and the duration of time
in setback. The Boost setting allows the installer to set the
maximum amount of time that Boost can remain in effect.
Boost is shown on the display while boost is in effect.
building temperature at night, there is a time delay to
increase the building temperature from the Unoccupied to
Occupied temperature. The control shortens the recovery
time by determining how long the steam boiler needs to
operate at 100% on time of a heating cycle and the boost
can continue through multiple heating cycles. The length
of the boost is determined by the temperature difference
Building
Temperature
Occupied OccupiedUnoccupied
Setback Period Boost
% On Time
Per Cycle
Limited Unoccupied Section L
The control includes a Limited Unoccupied feature that is
available in the Adjust menu. When the Limited Unoccupied
is set to on and the heating cycle reaches 85% on time, the
control is prevented from going into the Unoccupied mode in
order to avoid long recovery times. If the control is already
in the Unoccupied mode and the outdoor temperature drops
so that the heating cycle on time exceeds 85%, the control
will switch back into the Occupied mode. When the Limited
Unoccupied is set to off, the control continues to operate
on the regular Occupied/Unoccupied schedule, regardless
of the heating cycle on time.
Alert Relay Operation Section M
The alert relays can be used to connect to security systems,
alarm panels or telephone dialers to provide an alert signal
should the control have an error message present.
Note: The 279 is not a UL approved alarm panel.
Alert 2 Relay
The Alert 2 Relay closes when the outdoor, condensate,
room 1, room 2, or DHW tankless coil sensor has either
an open or short circuit.
Alert 1 Relay
The Alert 1 Relay closes when the control has an E01
Memory Error message, or when either Room 1 or Room
2 sensor measures a temperature below 38°F (3.5°C).
9 of 24 © 2010 D 279 - 05/10
Page 10
Domestic Hot Water Tankless Coil Section N
The control can replace the mechanical aquastat in the
steam boiler that operates a tankless coil domestic hot
water system with an optional DHW Tankless Coil Sensor.
The sensor is installed into the 1/2” (12 mm) immersion well
that measures the temperature of the tankless coil.
Universal
Sensor
The advantage of using the DHW Tankless Coil feature
is that the control can be programmed to operate the
tankless coil on a night setback schedule. This can lower
fuel usage for domestic hot water heating. The DHW
tankless coil operation of the boiler is separate from the
steam heating operation and is not affected by the heating
system settings.
It is recommended that an anti-scald valve be installed on
the domestic hot water system.
Once the sensor is installed, the DHW Tankless Coil
Sensor/Off switch setting must be set to DHW Tankless
Coil. The DHW Exchange (DHW XCHG) temperature is
visible in the View menu and is a measurement of the DHW
Tankless Coil Sensor. The DHW Tankless Coil temperature
can be set using the DHW XCHG Occupied and the DHW
XCHG Unoccupied settings in the Adjust menu. When the
steam boiler is turned on for DHW tankless coil heating,
the Status field will have a pointer indicating DHW Tankless
Coil Heating.
The DHW Exchange Occupied and Unoccupied target
temperature is maintained with a fixed differential of
10°F (5.5°C). The differential is half above and half
below the target.
Installation
Caution
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
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 279 includes:
One Steam Control 279, One Outdoor Sensor 070, One
Universal Sensor 071, Data Brochures D 279, D 070, D 001,
Application Brochure A 279.
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.
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.
© 2010 D 279 - 05/10 10 of 24
Page 11
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 Indoor Sensor 076, 077, or 084 according to the
installation instruction in the Data Brochure D 076, D 077,
or D 084 and run the wiring back to the control.
Install the Condensate Sensor 071 according to the
•
installation instructions in the Data Brochure D 070 and
run the wiring back to the control.
Install the DHW Tankless Coil 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 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 Connections Terminals 1, 2
115 V (ac) Power
Connect the 115 V (ac) power supply to the Power L and
Power N terminals (1 and 2). This connection provides
power to the microprocessor and display of the control.
Steam
Control 279
L
N
115 V (ac)
1 2
Power
LN
Output Connections Terminals 3 - 8
Alert 1
The Alert 1 terminals (3 and 4) are isolated outputs 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 a signal to a security system, alarm
Steam
Control 279
34
Alert 1
High
panel, or telephone dialer. Since this is an isolated contact,
it may switch a voltage up to 230 V (ac).
Note: Alert 1 requires a minimum current of 0.1 A in order
to keep the contact functioning properly.
Alert 2
The Alert 2 terminals (5 and 6) are isolated outputs in the
control. There is no power available on these terminals from
the control. These terminals are to be used as a switch to
Steam
Control 279
56
Alert 2
Low
either make or break a signal to a security system, alarm
panel, or telephone dialer. Since this is an isolated contact,
it may switch a voltage up to 230 V (ac).
Note: Alert 2 requires a minimum current of 0.1 A in order
to keep the contact functioning properly.
11 of 24 © 2010 D 279 - 05/10
Alert
Monitor
Device
Alert
Monitor
Device
Page 12
Boiler
The Boiler terminals (7 and 8) are isolated outputs 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 the thermostat input on a
steam boiler or the power to a steam valve. Since this is
an isolated contact, it may switch a voltage between 24 V
(ac) and 230 V (ac).
Steam
Control 279
78
Boiler
T-T contacts
on boiler
OR
L or R
N or C
Valve
Sensor and Unpowered Input Connections Terminals 10 - 16
Do not apply power to these terminals as this will
damage the control.
(24 to
230 V (ac))
Outdoor Sensor
Connect the two wires from the Outdoor Sensor 070 to the
Com Sen and Out Sen terminals (14 and 16). The outdoor
sensor is used by the control to measure the outdoor air
temperature.
Condensate Sensor
Connect the two wires from the Condensate Sensor 071
to the Com Sen and Cdn Sen terminals (14 and 15). The
condensate sensor is used by the control to measure the
condensate temperature.
Indoor Sensor S1
Connect the two wires from the Indoor Sensor 076, 077,
or 084 to the Com Sen and Indr S1 terminals (10 and 13).
The indoor sensor is used by the control to measure the
room air temperature.
Indoor Sensor S2
Connect the two wires from the Indoor Sensor 076, 077,
or 084 to the Com Sen and Indr S2 terminals (10 and 12).
The indoor sensor is used by the control to measure the
room air temperature.
Steam
Control 279
Steam
Control 279
Steam
Control 279
Steam
Control 279
14 15 16
Com
Cdn Out
Sen Sen Sen
14 15
Com
Cdn
Sen Sen
10 11 12 13
Com
DHW
Indr Indr
Sen Sen S2 S1
10 11 12
Com
DHW
Indr
Sen Sen S2
Outdoor
Sensor 070
Condensate
Sensor 071
Indoor Sensor
076, 077 or 084
DHW Tankless Coil Sensor
Connect the two wires from the DHW Tankless Coil Sensor
082 to the Com Sen and DHW Sen terminals (9 and 11).
The DHW tankless coil sensor is used by the control to
measure the tankless coil temperature.
© 2010 D 279 - 05/10 12 of 24
Steam
Control 279
91011
Com
Com
DHW
Sen Sen Sen
Indoor Sensor
076, 077 or 084
DHW
Tankless Coil
Sensor 082
Page 13
Step Five — Testing the Wiring
General
Each terminal block must be unplugged from its header on
the control before power is applied for testing. To remove
the terminal block, pull straight down from the control.
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.
Test the Sensors
In order to test the sensors, the actual temperature at
each sensor location must be measured. A good quality
digital thermometer with a surface temperature probe is
recommended for ease of use and accuracy. Where a
digital thermometer is not available, a spare sensor can be
strapped alongside the one to be tested and the readings
compared. Test the sensors according to the instructions
in the Data Brochure D 070.
Test the Power Supply
Make sure exposed wires and bare terminals are not in
contact with other wires or grounded surfaces. Turn on the
power and measure the voltage between the Power L and
Power N terminals (1 and 2) using an AC voltmeter, the
reading should be between 103.5 and 126.5 V (ac).
A good quality electrical test meter, capable of reading from
at least 0 – 300 V (ac) and at least 0 – 2,000,000 Ohms, is
essential to properly test the wiring and sensors.
V
14 15
Com
Cdn
Sen Sen
1 2
Power
LN
N
L
Test the Outputs
Alert 1
If a security system, alarm panel, or telephone dialer
is connected to the Alert 1 terminals (3 and 4), install a
jumper wire between the terminals. The security system,
alarm panel, or telephone dialer should respond. If the
security system, alarm panel, or telephone dialer does not
respond properly, refer to any installation or troubleshooting
information supplied with the security system, alarm panel,
or telephone dialer equipment. If the security system, alarm
panel, or telephone dialer operates properly, then remove
the jumper wire.
Alert 2
If a security system, alarm panel, or telephone dialer
is connected to the Alert 2 terminals (5 and 6), install a
jumper wire between the terminals. The security system,
alarm panel, or telephone dialer should respond. If the
security system, alarm panel, or telephone dialer does not
respond properly, refer to any installation or troubleshooting
information supplied with the security system, alarm panel,
or telephone dialer equipment. If the security system, alarm
panel, or telephone dialer operates properly, remove the
jumper wire.
Jumper wire
between
terminals
Jumper wire
between
terminals
34
Alert 1
High
56
Alert 2
Low
Alert
Monitor
Device
Alert
Monitor
Device
13 of 24 © 2010 D 279 - 05/10
Page 14
Boiler
If a steam boiler or steam valve is connected to the Boiler
terminals (7 and 8), make sure power to the boiler circuit
is off and install a jumper between the terminals. When the
circuit is powered up, the boiler should fire or the steam
valve should open. If the boiler or steam valve does not turn
on, refer to any installation or troubleshooting information
supplied with the boiler or steam valve. If the boiler or
steam valve operates properly, disconnect the power and
remove the jumper.
Connecting the Control
Make sure all power to the devices and terminal blocks is off,
and remove any remaining jumpers from the terminals.
Reconnect the terminal blocks to the control by carefully
aligning them with their respective headers on the control,
and then pushing the terminal blocks into the headers. The
terminal blocks should snap firmly into place.
Install the supplied safety dividers between the unpowered
sensor inputs and the powered or 115 V (ac) wiring
chambers.
Apply power to the control. The operation of the control
on power up is described in the Sequence of Operation
section of the brochure.
Jumper wire
between
terminals
Steam
Control 279
78
Boiler
9
Com
Sen
10
Com
Sen
11
DHW
Sen
Indr
S2
12
OR
Indr
13
S1
14
Com
Sen
Valve
15
Cdn
Sen
T-T contacts
on boiler
L or R
N or C
16
Out
Sen
(24 to
230 V (ac))
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 the
control. Do not use solvents or cleaning solutions.
© 2010 D 279 - 05/10 14 of 24
Page 15
Switch Settings
GENERAL
The switch settings on the control are very important and
should be set to the appropriate settings prior to making
any adjustments to the control through the User Interface.
The switch settings change the items that are available to
be viewed and/or adjusted in the User Interface.
If a switch setting is changed while the control is powered
up, the control responds to the change in setting by returning
the display to the VIEW menu.
Switch Settings
Installer/User
The Installer/User switch selects the access level of the
control. In the User access level, a limited number of items
may be viewed and adjusted. In the Installer access level,
all items may be viewed and adjusted.
Average/Off
The Average/Off switch only applies when both indoor
sensor S1 and S2 are on and both indoor sensors are
present.
If the switch is set to Average, the control operates the
steam system based on the average of the two indoor
sensor temperature readings. If the switch is set to Off, the
control operates the steam system based on the coldest of
the two indoor sensor temperature measurements.
Condensate Sensor/Off
The Condensate Sensor/Off switch selects whether or
not a condensate sensor is connected to the Condensate
Sensor terminals (14 and 15).
DHW Tankless Coil Sensor/Off
The DHW Tankless Coil Sensor/Off switch selects whether
or not a DHW tankless coil sensor is connected to the DHW
Sensor terminals (9 and 11).
Indoor S1/Off
The Indoor S1/Off switch selects whether or not an indoor
sensor is connected to the indoor sensor S1 terminals
(10 and 13).
Indoor S2/Off
The Indoor S2/Off switch selects whether or not an indoor
sensor is connected to the indoor sensor S2 terminals (10
and 12).
Setback/Off
The Setback/Off switch selects whether or not the internal
setback timer and schedule is to be used. If the switch is set
to Setback, the time must be set and the setback schedule
must be entered in order to provide setback events.
15 of 24 © 2010 D 279 - 05/10
Page 16
Display Menus
View Menu (1 of 1)
The View menu items display the current operating
temperatures and status information of the system.
Item Field Range
VIEW MENU
-76 to 149°F
(-60.0 to 65.0°C)
-31 to 266°F
(-35.0 to 130.0°C)
-49 to 203°F
(-45.0 to 95.0°C)
35 to 100°F
(1.5 to 38.0°C)
-31 to 266°F
(-35.0 to 130.0°C)
-31 to 266°F
(-35.0 to 130.0°C)
Access
User
User
User
Installer
Installer
Installer
Description
OUTDOOR SECTION C
Current outdoor air temperature as measured by the
outdoor sensor.
ROOM 1 SECTION F
Current room air temperature as measured by indoor
sensor 1.
Available when:
Indoor Sensor S1/Off switch setting is set to S1.•
ROOM 2 SECTION F
Current room air temperature as measured by indoor
sensor 2.
Available when:
Indoor Sensor S2/Off switch setting is set to S2.•
ROOM TARGET SECTION F
Desired temperature of the building.
Available when:
Indoor Sensor S1/Off switch setting is set to S1.
OR
Indoor Sensor S2/Off switch setting is set to S2.•
CONDENSATE SECTION B
Current condensate return temperature as measured
by the condensate sensor.
Available when:
Condensate/Off switch setting is set to Condensate.•
DHW EXCHANGE SECTION N
Current DHW tankless coil temperature as measured
by the tankless coil sensor.
Available when:
DHW Tankless Coil Sensor/Off switch settings is
•
set to DHW Tankless Coil Sensor.
0 to 100 %
0 to 9999 hours
After the last item, the control returns to the first item in the menu.
© 2010 D 279 - 05/10 16 of 24
Installer
User
BOILER % SECTION C
The calculated percentage on time of a heating cycle
that the steam boiler will operate.
BOILER HOURS
The total running time that the boiler contact was
closed since this item was last cleared. Press Up and
Down buttons together to zero the boiler hours.
Page 17
Adjust Menu (1 of 3)
Item Field Range Access Description Actual Setting
The Adjust Menu items are the programmable settings used
to operate the mechanical equipment.
ADJUST MENU
35 to 100°F
(1.5 to 38.0°C)
Default = 70°F
(21.0°C)
35 to 100°F
(1.5 to 38.0°C)
Default = 65°F
(18.5°C)
OFF, On
Default = OFF
OFF, 0:20 to
8:00 hr
Default = OFF
User
User
Installer
Installer
ROOM OCCUPIED SECTION F
Select the desired room temperature of the
building during the occupied period.
ROOM UNOCCUPIED SECTION F
Select the desired room temperature of the
building during the unoccupied period.
Available when:
Setback/Off switch setting is set to Setback.•
OPTIMUM START SECTION J
Select whether or not optimum start should be
used to recover from Unoccupied to Occupied
temperature.
Available when:
Setback/Off switch setting is set to Setback.
•
AND
Indoor Sensor S1/Off switch setting is set to
•
S1 or Indoor Sensor S2/Off switch setting is
set to S2.
BOOST SECTION K
Select the maximum amount of time that boost
can be in effect to recover from Unoccupied to
Occupied temperature.
Available when:
Setback/Off switch setting is set to Setback.
•
AND
Indoor Sensor S1/Off switch setting is set to
•
Off and Indoor Sensor S2/Off switch setting
is set to Off.
LIMITED UNOCCUPIED SECTION L
OFF, On
Default = OFF
-60 to 30°F
(-51.0 to -1.0°C)
Default = 10°F
(-12.0°C)
5 to 100%
Default = 100%
Continued on next page.
17 of 24 © 2010 D 279 - 05/10
Installer
Installer
User
Select if the night setback should be limited once
the boiler % reaches 85% on time.
Available when:
Setback/Off switch setting is set to Setback.•
OUTDOOR DESIGN SECTION C
Select the design outdoor air temperature used
in the heat loss calculations for the heating
system. Typically set to the temperature of the
coldest day of the year.
BOILER DESIGN PERCENT SECTION C
Select the boiler percent output when the outdoor
temperature reaches the outdoor design setting.
Reduce the percentage if the boiler is oversized
for the building.
Page 18
Adjust Menu (2 of 3)
Item Field Range Access Description Actual Setting
35 to 100°F
(1.5 to 38.0°C)
Default = 70°F
(21.0°C)
Auto, 20 to 100
min
Default = 60 min
100 to 220°F
(38.0 to
104.5°C)
Default = 180°F
(82.0°C)
OFF, 5 to 100°F
(OFF, 3.0 to
38.0°C)
Default = 25°F
(14.0°C)
Installer
Installer
Installer
Installer
INDOOR DESIGN
Select the design indoor air temperature used
in the heat loss calculations. Typically set to the
desired indoor temperature.
CYCLE
Select the length of the heating cycle in minutes.
Auto setting is only available when indoor
sensors are present.
STEAM ESTABLISHED
Select the condensate return temperature
at which steam is established at the furthest
radiator.
Available when:
•
LOCKOUT DIFFERENTIAL
Select the number of degrees below the steam
established temperature at which to start the
next heating cycle.
Available when:
•
SECTION D
Condensate Sensor/Off switch setting is set
to Condensate Sensor.
Condensate Sensor/Off switch setting is set
to Condensate Sensor.
SECTION C
SECTION B
SECTION E
ADJUST MENU
0 to 50 min
Default = 0 min
140 to 200°F
(60.0 to 93.5°C)
Default = 160°F
(71.0°C)
OFF, 140 to
200°F
(OFF, 60.0 to
93.5°C)
Default = OFF
Installer
Installer
Installer
MINIMUM ON TIME
Select the length of time in minutes to establish
steam at the furthest radiator.
Available when:
Condensate Sensor/Off switch setting is set
•
to Off.
DHW EXCHANGE OCCUPIED
Select the tankless coil temperature required
for domestic hot water during the occupied
time period.
Available when:
DHW Tankless Coil Sensor/Off switch setting
•
is set to DHW Tankless Coil Sensor.
DHW EXCHANGE UNOCCUPIED
Select the tankless coil temperature required
for domestic hot water during the unoccupied
time period.
Available when:
DHW Tankless Coil Sensor/Off switch setting
•
is set to DHW Tankless Coil Sensor.
AND
Setback/Off switch setting is set to Setback.
•
SECTION B
SECTION N
SECTION N
Continued on next page.
© 2010 D 279 - 05/10 18 of 24
Page 19
Adjust Menu (3 of 3)
Item Field Range Access Description Actual Setting
ADJUST MENU
35 to 100°F
(1.5 to 38.0°C)
Default = 65°F
(18.5°C)
35 to 100°F
(1.5 to 38.0°C)
Default = 60°F
(15.5°C)
°F or °C
Default = °F
User
User
User
WARM WEATHER SHUT DOWN
OCCUPIED
Select the steam system’s warm weather shut
down temperature during the occupied period.
WWSD does not affect DHW Tankless Coil
operation.
WARM WEATHER SHUT DOWN
UNOCCUPIED SECTION I
Select the steam system’s warm weather shut
down temperature during the unoccupied period.
WWSD does not affect DHW Tankless Coil
operation.
Available when:
Setback/Off switch setting is set to Setback.•
TEMPERATURE UNITS
Select to display temperature in °F or °C.
SECTION I
After the last item, the control returns to the first item in the menu.
Time Menu
Note: The Setback / Off switch setting must be in the Setback position in order to have access to the TIME menu.
Setting the Time
Step 1
Press and release the Menu button until the TIME menu is reached.
Step 2
Press the Item button. While the minutes are flashing, use the or button to set the minutes.
Step 3
Press and release the Item button. While the hours are flashing, use the or button to set
the hour.
Step 4
Press and release the Item button. While the day is flashing, use the or button to set the day.
Step 5 (Only available in Installer access level)
Press and release the Item button. Use the or button to select between 12 and 24 hour time.
19 of 24 © 2010 D 279 - 05/10
Page 20
Schedule Menu
Note: The Setback/Off switch setting must be in the Setback position in order to have access to the SCHEDULE menu.
Setting the Schedule
A schedule allows the control to automatically change between the Occupied and Unoccupied temperature settings based
on the time of day.
A two-event schedule divides the day into Occupied and Unoccupied time periods. A four-event schedule divides the day
into Occupied 1, Unoccupied 1, Occupied 2, and Unoccupied 2 time periods.
To set the time of day at which each period is to begin, use the following procedure.
Step 1
Press and release the Menu button until the Schedule
menu is displayed.
Step 2 (Only available in installer access level.)
Use the or button to select a 24 hour, 5-1-1 day, or
a 7 day schedule.
Step 3 (Only available in installer access level.)
Press and release the Item button.
Use the
or button to select either a two-event or four-
event schedule.
Step 4
Press and release the Item button. Use the or button to
set the event’s beginning time. If the event is not required,
select the “– – : – –” time. This time is found between 11:50
PM and 12:00 AM. Press the Item button to advance to the
next setting.
Testing the Control
The control has a built-in test routine that is used to test the main control functions. The control
continually monitors the sensors and displays an error message whenever a fault is found. See
the following pages for a list of the control’s error messages and possible causes. When the
Test button is pressed, the Test light is turned on. The individual outputs and relays are tested
in the following test sequence.
© 2010 D 279 - 05/10 20 of 24
Test
off
red
red
not testing
testing
testing paused
Page 21
Test Sequence
Each step in the test sequence lasts 10 seconds.
During the test routine, the test sequence may be paused
by pressing the Test button. If the Test button is not pressed
again for 5 minutes while the test sequence is paused, the
control exits the entire test routine. If the test sequence is
paused, the Test button can be pressed again to advance
to the next step. This can also be used to rapidly advance
through the test sequence. To reach the desired step,
repeatedly press and release the Test button until the
appropriate device and segment in the display turn on.
Max Heat
The control has a function called Max Heat. In this mode,
the control turns on and operates the steam system at the
percent output selected. The control continues to operate
in this mode for up to 24 hours or until the Menu, Item or
Test button is pressed.
To enable the Max Heat feature, use the following
procedure.
Press and hold the Test button for more than 3
1.
seconds. At this point, the control flashes the MAX
HEAT segment and displays the word OFF.
Step 1
Turn on the Boiler relay for 10 seconds, then
shut off.
Step 2
Turn on the Alert 1 relay for 10 seconds,
then shut off.
Step 3
Turn on the Alert 2 relay for 10 seconds,
then shut off.
Using the or button, select the word On. After 3
2.
seconds the Boiler % is shown.
Select the desired boiler output percentage using the
3.
or buttons.
To cancel the Max Heat mode, press the Menu, Item,
4.
or Test button.
Once the Max Heat mode has either ended or is
5.
cancelled, the control resumes normal operation.
Menu Item Menu Item Menu Item
Troubleshooting
When troubleshooting any heating system, it is always a good idea to establish a set routine to follow. By following a
consistent routine, many hours of potential headaches can be avoided. Below is an example of a sequence that can be
used when diagnosing or troubleshooting problems in a steam heating system.
Establish the problem. Get as much information from the customer as possible about the problem.
Establish the
Problem
Understanding
the Sequence of
Operation
Use the Test
Routine
Sketch the
Piping in the
System
Is there too much heat, not enough heat, or no heat? Is the problem only in one particular zone or
area of the building or does the problem affect the entire system? Is this a consistent problem or only
intermittent? How long has the problem existed for? This information is critical in correctly diagnosing
the problem.
Understand the sequence of operation of the system. If a particular zone is not receiving enough heat,
which pumps or valves in the system must operate in order to deliver heat to the affected zone? If the
zone is receiving too much heat, which pumps, valves or check valves must operate in order to stop
the delivery of heat?
Press the Test button on the control and follow the control through the test sequence as described in
the Testing section. Pause the control as necessary to ensure that the correct device is operating as
it should.
Sketch the piping of the system. This is a relatively simple step that tends to be overlooked, however
it can often save hours of time in troubleshooting a system. Note flow directions in the system paying
close attention to the location of pumps, check valves, pressure bypass valves and mixing valves. Ensure
correct flow direction on all pumps. This is also a very useful step if additional assistance is required.
21 of 24 © 2010 D 279 - 05/10
Page 22
Document the control for future reference. Before making any adjustments to the control, note down
Document the
Control
Isolate the
Problem
Test the Contacts,
Voltages and
Sensors
all of the items that the control is currently displaying. This includes items such as error messages,
current temperatures and settings, and which devices should be operating as indicated by the LCD.
This information is an essential step if additional assistance is required to diagnose the problem.
Isolate the problem between the control and the system. Now that the sequence of operation is known
and the system is sketched, is the control operating the proper pumps and valves at the correct times?
Is the control receiving the correct signals from the system as to when it should be operating? Are the
proper items selected in the menus of the control for the device that is to be operated?
Test the contacts, voltages and sensors. Using a multimeter, ensure that the control is receiving
adequate voltage to the power terminals and the demand terminals as noted in the technical data. Use
the multimeter to determine if the internal contacts on the control are opening and closing correctly.
Follow the instructions in the Testing the Wiring section to simulate closed contacts on the terminal
blocks as required. Test the sensors and their wiring as described in the sensor Data Brochures.
Error Messages (1 of 2)
E01 MEMORY ERROR
The E01 memory error message causes the Alert 1 High relay to turn on.
The control was unable to read a piece of information stored in its memory. Because of this,
the control was required to reload the factory settings into all of the items in the ADJUST menu.
The control continues operation using the factory defaults until all of the items in the ADJUST
menu of the control have been checked by the installer.
Note: The Installer/User switch must be set to Installer in order to clear the error.
OUTDOOR SENSOR SHORT CIRCUIT
The outdoor sensor short circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the outdoor sensor due to a short circuit. In this case the
control assumes an outdoor temperature of 32°F (0°C) and continues operation. Locate and
repair the problem as described in the Data Brochure D 070. To clear the error message from
the control after the sensor has been repaired, press any button.
OUTDOOR SENSOR OPEN CIRCUIT
The outdoor sensor open circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the outdoor sensor due to an open circuit. In this case
the control assumes an outdoor temperature of 32°F (0°C) and continues operation. Locate
and repair the problem as described in the Data Brochure D 070. To clear the error message
from the control after the sensor has been repaired, press any button.
CONDENSATE SENSOR SHORT CIRCUIT
The condensate sensor short circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the condensate sensor due to a short circuit. In this case
the control operates as if the condensate sensor was not connected so that there is no time
allowed for establishing steam and no lockout differential. Locate and repair the problem as
described in the Data Brochure D 070. To clear the error message from the control after the
sensor has been repaired, press any button.
CONDENSATE SENSOR OPEN CIRCUIT
The condensate sensor open circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the condensate sensor due to an open circuit. In this case
the control operates as if the condensate sensor was not connected so that there is no time
allowed for establishing steam and no lockout differential. Locate and repair the problem as
described in the Data Brochure D 070. To clear the error message from the control after the
sensor has been repaired, press any button.
If the condensate sensor was removed on purpose, set the Condensate/Off switch to Off.
© 2010 D 279 - 05/10 22 of 24
Page 23
Error Messages (2 of 2)
ROOM 1 SHORT CIRCUIT
The room 1 short circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the indoor sensor 1 due to a short circuit. In this case
the control will continue operation using indoor sensor 2. If indoor sensor 2 is not available,
then the control operates without using indoor temperature feedback. Locate and repair the
problem as described in the Data Brochure D 076, D 077, or D 084. To clear the error message
from the control after the sensor has been repaired, press any button.
ROOM 1 OPEN CIRCUIT
The room 1 open circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the indoor sensor 1 due to an open circuit. In this case
the control will continue operation using indoor sensor 2. If indoor sensor 2 is not available,
then the control operates without using indoor temperature feedback. Locate and repair the
problem as described in the Data Brochure D 076, D 077, or D 084. To clear the error message
from the control after the sensor has been repaired, press any button.
If indoor sensor 1 was removed on purpose, set the Indoor S1/Off switch to Off.
ROOM 2 SHORT CIRCUIT
The room 2 short circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the indoor sensor 2 due to a short circuit. In this case
the control will continue operation using indoor sensor 1. If indoor sensor 1 is not available,
then the control operates without using indoor temperature feedback. Locate and repair the
problem as described in the Data Brochure D 076, D 077, or D 084. To clear the error message
from the control after the sensor has been repaired, press any button.
ROOM 2 OPEN CIRCUIT
The room 2 open circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the indoor sensor 2 due to an open circuit. In this case
the control will continue operation using indoor sensor 1. If indoor sensor 1 is not available,
then the control operates without using indoor temperature feedback. Locate and repair the
problem as described in the Data Brochure D 076, D 077, or D 084. To clear the error message
from the control after the sensor has been repaired, press any button.
If indoor sensor 2 was removed on purpose, set the Indoor S2/Off switch to Off.
DHW EXCHANGE SHORT CIRCUIT
The DHW exchange sensor short circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the DHW tankless coil sensor due to a short circuit. In this
case the control does not operate the steam boiler for tankless coil domestic hot water. Locate
and repair the problem as described in the Data Brochure D 070. To clear the error message
from the control after the sensor has been repaired, press any button.
DHW EXCHANGE OPEN CIRCUIT
The DHW exchange sensor open circuit error message causes the Alert 2 Low relay to turn on.
The control is no longer able to read the DHW tankless coil sensor due to an open circuit. In
this case the control does not operate the steam boiler for tankless coil domestic hot water.
Locate and repair the problem as described in the Data Brochure D 070. To clear the error
message from the control after the sensor has been repaired, press any button.
If the DHW tankless coil sensor was removed on purpose, set the DHW Tankless Coil Sensor/
Off switch to Off.
NO HEAT
The no heat error message causes the Alert 1 High relay to turn on.
One of the indoor sensors has measured a temperature below 38°F (3.5°C). To clear the
error message from the control, press any button after the indoor sensor temperature has
exceeded 38°F (3.5°C).
23 of 24 © 2010 D 279 - 05/10
Page 24
Technical Data
Steam Control Control 279 One Stage
Literature — D 279, A 279, D 001, D 070
Control — Microprocessor control; This is not a safety (limit) control
Packaged weight — 3.3 lb. (1500 g)
— 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 — CSA C US, meets ICES & FCC regulations for EMI/RFI
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 3.5 VA
Relays — 230 V (ac) 5 A 1/3 hp, pilot duty 240 VA
Sensors — NTC thermistor, 10 kΩ @ 77°F (25°C ±0.2°C) ß=3892
included: — Outdoor Sensor 070 and Universal Sensor 071
Optional Devices — tekmar type #: 071, 076, 077, 078, 082, 084
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 parts 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 cost 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 BE YON D TW ENT Y-FOU R (24) M ONTHS F ROM THE PRODU CTION DATE, TO THE EXTENT 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., Canada
tekmar Control Systems, Inc., U.S.A.
Head Office: 5100 Silver Star Road
Vernon, B.C. Canada V1B 3K4
(250) 545-7749 Fax. (250) 545-0650
Web Site: www.tekmarcontrols.com
Product design, software and literature are Copyright © 2010 by:
tekmar Control Systems Ltd. and tekmar Control Systems, Inc.
24 of 24
All specifications are subject to change without notice.
Printed in Canada. D 279 - 05/10.
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