tekmar 284 User Manual
Installation & Operation Manual
Boiler Control 284
Multi-Staging
A Flexible Solution for Commercial & Multi-Residential Heating Plants
D 284
08/14
Replaces: 04/14
The Boiler Control 284 is designed to operate up to four
boilers to accurately maintain a target water temperature.
The 284 operates both condensing & non-condensing boilers
that are either modulating, single stage or two stage to
provide a flexible, cost effective mixed boiler plant solution
with better system performance.
The target water temperature is based on outdoor temperature
reset or a fixed setpoint for space or process heating
applications. Additional loads supplied by the 284 include
domestic hot water & fixed setpoint heating. Boiler equal
run-time rotation, stand-by primary pump operation & pump
exercising all increase boiler plant reliability.
The 284 communicates with a Building Automation System
(BAS) using BACnet® IP or Modbus® for remote monitoring
& adjustment capability. tekmarNet® Thermostats or a tN4
Gateway 483 can be added to optimize system performance
& provide remote monitoring capability.
Features
•
Outdoor temperature reset
•
Programmable schedules
•
tekmarNet
•
Control up to four boilers
•
Condensing & non-condensing boiler groups
•
Modulating, single stage or two stage
•
Boiler isolation valves
•
BACnet
•
Primary pump sequencing
•
DHW priority
•
Setpoint operation
•
Combustion air damper control
•
Energy, flow & pressure monitoring
®
compatible
®
IP or Modbus® communication
A Watts Water Technologies Company
BACnet is a registered trademark of ASHRAE.
ASHRAE does not endorse, approve or test products
for compliance with ASHRAE standards. Compliance of
listed products to the requirements of ASHRAE Standard
135 is the responsibility of BACnet International (BI).
BTL is a registered trademark of BI.
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Benefi ts
•
Reduce energy costs
•
Prolong equipment life
•
Provide boiler redundancy
•
Provide primary pump redundancy
•
Remote monitoring & adjustment options
•
Combine mid & high efficiency boilers to lower
component cost
© 2014 284_D - 08/14
Table of Contents
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Sequence of Operation .....................................................2
Boiler Setup ................................................................... 2
System Setup ................................................................ 5
Boiler Plant Operation ................................................... 7
Outdoor Temperature Reset Operation ...................... 10
Setpoint Operation ...................................................... 12
Energy Management System (EMS) Operation .......... 13
Indirect Domestic Hot Water (IDHW) Operation ..........14
Dedicated Domestic Hot Water (DDHW) Operation ....17
Building Automation System (BAS) Operation .............17
Pump Operation .......................................................... 18
C.A. Damper & DHW Recirculation ............................. 20
Setting the Schedule ................................................... 20
Time Clock ................................................................... 21
tekmarNet
Installation .......................................................................22
Installation Location ..................................................... 22
Control Wiring .............................................................. 23
Sensor Installation & Wiring ........................................ 26
EMS, Modbus
Wiring the tekmarNet
Testing the Sensor Wiring ...........................................30
®
4 Communication ...................................... 21
®
& BACnet® Connections ....................29
®
Devices ................................... 30
Testing the Control Wiring ............................................... 31
Control Settings ...............................................................33
Access Level ............................................................... 33
DIP Switch Settings ..................................................... 33
User Interface ..................................................................34
Display & Symbols....................................................... 34
Navigating the Display ................................................. 35
View Menu .................................................................. 35
Setup Menu ................................................................ 37
Source # Menu ............................................................43
BAS Menu .................................................................... 45
Monitor # Menu ............................................................ 47
Monitor Menu .............................................................. 48
Time Menu ................................................................. 50
Schedule Menu ...........................................................51
Toolbox Menu .............................................................52
Manual Override ......................................................... 54
Troubleshoot ing ...............................................................56
Error Messages ..........................................................56
Technical Data ............................................................60
Limited Warranty & Product Return Procedure...............60
Sequence of Operation
Boiler (Source (#) Menu) Setup & Operation
The 284 is able to operate up to four boilers as a heat source.
Each boiler is independently configured allowing for maximum
plant flexibility.
Boiler Enable
This setting selects whether the boiler is operational or not.
OFF
The boiler is disabled & will not be included in the plant
operation.
AUTO
The boiler is enabled & will be included in the plant
operation.
Copy Boiler 1
Many boiler installations will have multiple identical boilers.
To reduce the number of settings required, certain settings
of boiler 1 are copied to boiler 2 by setting the Boiler 2 Copy
setting to Boil1. Copy settings are also available for boiler 3
& boiler 4.
OFF
The settings from boiler 1 are not copied. This allows for
individual boiler settings.
Boil 1
The settings from boiler 1 are copied.
Condensing
This setting selects whether the boiler is condensing or noncondensing & defines what boiler group it is part of.
NO
The boiler is non-condensing & is part of the non-condensing
boiler group.
YES
The boiler is condensing & is part of the condensing boiler group.
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Boiler Type
The 284 has four different boiler types to choose from. Use
the Boil TYPE setting to select one of the following:
MOD
The modulating output operates a modulating boiler by controlling
the burner firing rate. The Stage 1 relay is also used to give
a boiler enable to allow the modulating boiler to go through
ignition sequence. The Stage 1 relay may not be required on
all modulating boilers.
1STG
The Stage 1 relay operates a single, stage boiler by cycling
the burner stage on & off.
2STG
The Stage 1 & Stage 2 relays operate a single, two stage boiler
by cycling the burner stages on & off.
EMS
The modulating output operates a boiler that interprets an
analog input signal as a target temperature. The temperature
rails (minimum and maximum) are adjustable between 50°F
(10.0°C) & 210°F (99.0°C).
VDC SIGN MIN
•
Sets the minimum analog Vdc signal which corresponds to
the minimum temperature (EMS TEMP MIN).
EMS TEMP MIN
•
Sets the temperature on the low end which corresponds to the
minimum analog signal (Vdc Min / 4 mA).
EMS TEMP MAX
•
Sets the temperature on the high end which corresponds to
the maximum analog signal (10 Vdc / 20 mA).
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Modulating Type
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The MOD TYPE setting selects the analog output signal used
for modulating (MOD) and EMS boiler types.
0-10
The modulating output is 0-10 V (dc).
4-20
The modulating output is 4-20 mA.
The 4-20 mA output can be converted to a 0 - 135 Ω output
using a 0 - 135 Ω Converter 005. Refer to the Modulating Boiler
Wiring section of the Control Wiring section.
Fire Delay
The Fire Delay sets the time it takes for the boiler to
generate flame from the time the boiler turns on.
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can be set. This allows the control to properly operate the
boilers using either sequential or parallel modulation. Each
boiler typically has a rating plate that specifies the minimum
& maximum output. This information is also available in the
boiler manual.
The minimum & maximum boiler output is expressed in MBtu/h.
1 MBtu/h = 1,000 Btu / hour. The range is from 10 MBtu/h to
9,990 MBtu/h.
For example, if a boiler has a maximum output of 100,000
Btu / hr & a minimum output of 20,000 Btu / hr (turn down
ratio of 5):
Maximum Boiler Output = 100,000 = 100 MBtu/h
1,000
Boiler Contact Closed
Fire Delay
Burner On
Time
Modulation Delay
The MOD DELAY is the time that the boiler burner must hold
the modulation of the boiler at a minimum before allowing it to
modulate any further.
Boiler Mass
The Boil MASS setting selects the thermal mass characteristics
of each boiler. Operation of the boiler can become unstable if the
incorrect Boiler Mass setting is chosen. A key sign of unstable
boiler operation is that the flame will continue to increase & then
decrease in short periods of time. By choosing a lower boiler
mass setting, the boiler response will become more stable.
LOW
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 & 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 Low mass setting (LO) provides a fast response to the
heating system.
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 & a low metal content or a low water
content & 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 & 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 & steel tube boilers.
The Hi mass setting provides a slow response to the heating
system.
Low Fire & High Fire Boiler Output
In order to accommodate different boiler capacities in the
same system, a low fire & high fire boiler output for each boiler
A Watts Water Technologies Company
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Minimum Boiler Output = 20,000 = 20 MBtu/h
1,000
Motor Speed
The MOTOR SPD is the amount of time the boiler requires to
go from 0% modulation to 100% modulation.
Gas valve actuating motors have a design time from fully
closed to fully opened which can be found in the manufacturer’s
manual. The Motor Speed should be set to this time.
The Motor Speed setting for a Variable Frequency Drive (VFD)
is the amount of time required to go from a stopped position
to 100% fan speed. Since a VFD has a very quick response
rate, it may be necessary to increase the Motor Speed setting
in order to increase the stability of the boiler modulation.
Start Modulation
The START MOD setting is the lowest modulation output required
to obtain proper ignition. Whenever boiler operation is required,
the control outputs an analog signal corresponding to the Start
Modulation setting & closes the boiler contact to turn on the
burner. After the Fire Delay has elapsed & the burner is ignited,
the control modulates the firing rate between the Minimum
Modulation setting & the Maximum Modulation setting.
Minimum Modulation
The MIN MOD is the lowest signal the control can send to
modulate the boiler. This operates the boiler at low fire. Use the
MIN MOD setting in the Adjust Menu to select an appropriate
boiler minimum modulation.
Refer to the boiler manufacturer’s literature to determine
•
the minimum output voltage V (dc) or current (mA) that the
boiler will successfully operate at.
For 0 to 10 V (dc):
Minimum Modulation =
Boiler’s Minimum Input Signal
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OR
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x 100%
10 V (dc)
For 4 to 20 mA:
Minimum Modulation =
Boiler’s Minimum Input Signal - 4mA
x 100%
16 mA
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Example:
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A boiler requires a 1.8 V (dc) signal to fire the boiler at low fire.
The boiler can be modulated to 10 V (dc) where it reaches
high fire.
Minimum Modulation = 1.8 V x 100% = 18%
10 V
10 V (dc)
Control’s
Output
Signal
Range
Minimum
Modulation
0 V (dc)
Maximum Modulation
100%
88%
18%
0%
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10 V (dc)
Boiler’s
Input
Signal
Range
1.8 V (dc)
Boiler’s
Minimum
Input
Signal
The Maximum Modulation is the highest signal the control
can send to modulate the boiler. For boilers with electronic
operators, the boiler’s input signal range may not match the
output signal range of the 284. Use the MAX MOD setting in
the Source (#) Menu to select an appropriate boiler maximum
modulation.
For 0 to 10 V (dc):
Maximum Modulation =
Boiler’s Maximum Input Signal
x 100%
10 V (dc)
Maximum Boiler Outlet
---------------------------
The control has the capability for each boiler outlet temperature
to be monitored & limited. The MAX OUT setting sets the
maximum boiler outlet temperature. For modulating boilers,
as the boiler outlet temperature approaches the boiler outlet
maximum temperature, the control will reduce the firing rate.
Once the boiler outlet temperature reaches the boiler outlet
maximum temperature less 15°F (8.0°C), firing rate reduction
will begin. Once the boiler outlet temperature reaches the boiler
outlet maximum temperature less 5°F (2.5°C), the firing rate
will be reduced to minimum modulation. If the boiler outlet
temperature reaches the boiler outlet maximum, the boiler is
turned off. In order for the boiler to be able to be turned back
on again, the boiler outlet temperature must drop 5°F (2.5°C)
below the boiler outlet maximum.
If MAX OUT is set to OFF, the control only monitors the boiler
outlet temperature.
Boiler Pump / Valve Post Purge
-----------------------------
This setting sets the amount of time the control operates the
boiler pump / valve after the boiler is turned off. This will purge
heat out of the boiler, reducing stand-by losses, & also aid in
reducing “kettling”. The amount of time for the boiler pump post
purge is adjustable between 10 seconds & 20:00 minutes. Auto
is also available in which the control automatically determines
the amount of time based on the boiler mass.
For 4 to 20 mA:
Maximum Modulation =
Boiler’s Maximum Input Signal - 4mA
x 100%
16 mA
Example:
A boiler’s input signal range is 0 to 9 V (dc). The 284 control
has an output signal range of 0 to 10 V (dc).
Maximum Modulation = 9 V x 100% = 90%
10 V
10 V (dc)
Maximum
Modulation
Control’s
Output
Signal
Range
100%
90%
0%
9 V (dc)
Boiler’s
Input
Signal
Range
0 V (dc)0 V (dc)
Boiler’s
Maximum
Input
Signal
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System Setup & Operation
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Application Mode
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There are five possible application modes that the 284 can be
configured for including:
Outdoor Temperature Reset (RSET)
•
Fixed Setpoint (SETP)
•
Dedicated Domestic Hot Water (DDHW)
•
Energy Management System (EMS)
•
Building Automation System (BAS)
•
Refer to the appropriate section of this brochure for a description
of the each of the application modes.
Boiler Minimum
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The Boil MIN 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. MIN is displayed
in the status field while viewing the boiler supply or target &
when the boiler target is boiler minimum & 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.
The Boil MIN is only applicable when at least one of the
boilers is configured for non-condensing.
Boil MIN + 5°F (2.5°C)
Boiler Differential
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Boiler Maximum
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Boil MIN
The Boil MAX is the highest temperature that the control is
allowed to use as a boiler target temperature. MAX is displayed
in the status field viewing the boiler supply or target & when the
boiler target is boiler maximum & the boiler supply is greater
than boiler maximum minus 5°F (2.5°C). Set the boiler maximum
setting below the boiler operator or aquastat temperature.
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Boiler Differential
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Boil MAX
Boil MAX – 5°F (2.5°C)
Boiler Differential
Both on/off (single stage & two stage) & modulating boilers are
operated with a differential. In some cases, a modulating boiler
must be operated with a differential at low fire. This indicates
the load is smaller than the minimum modulation of the boiler.
For modulating boilers, the differential no longer applies once
operating the boiler above low fire.
The differential operates by turning on the boiler when the
boiler supply water temperature is 1/2 of the differential below
the boiler target temperature. As the boiler supply water
temperature reaches 1/2 of the differential above the boiler
target temperature, the boiler is shut off.
A Watts Water Technologies Company
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 – 1/2 Differential
Automatic Differential
Off
Exercising
Differential
Time
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On
The control will exercise all pumps, & tN4 zones (zone valves
& 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.
Boost
--------------------------------------------
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 Setup menu.
Typical settings for the boost function vary between 30 minutes
& 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 & 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.
If the building is not up to temperature at the correct time, the
BOOST setting should be lengthened & the setback timer should
be adjusted accordingly. If the building is up to temperature before
the required time, the BOOST setting should be shortened &
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.
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Target
Heating Load
Flow Monitoring
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The control has the capability to monitor flow rate through the
connection of a 4-20 mA style flow sensor. Flow is measured in
either gallons per minute (gpm) or meters cubed per hour (m3/h).
The units are adjustable through the FLOW UNIT setting in the
Toolbox menu.
Varying flow rates are accommodated & the flow range of the
flow sensor being used is configured using the following items
in the Setup menu:
FLOW RATE 4 mA
•
Sets the flow rate on the low end which corresponds to
4 mA.
•
FLOW RATE 20 mA
Sets the flow rate on the high end which corresponds to
20mA.
Examples of compatible aftermarket flow sensors include the
Kele SDI series, 2200 & 3100 series and 200 series (requires
310 transmitter).
In addition to flow monitoring, the flow sensor can also be
used to prove primary pump flow. Refer to the Pump Operation
section of this brochure for additional details.
Energy Monitoring
The control has the capability to monitor Energy. The control
requires the boiler supply, boiler return sensor & the flow
sensor in order to calculate & display energy in either Therms
(THRM) or Gigajoules (GJ). The units are adjustable through
the ENERGY UNIT setting in the Toolbox menu. Select MBtu
for display in THRM and kWh for display in GJ.
Pressure Monitoring
The control has the capability to monitor system pressure
through the connection of a V(dc) style pressure sensor with a
signal range of 0.5 to 4.5 V (dc). Pressure is measured in either
psi or kPa. The units are adjustable through the PRESSURE
UNIT setting in the Toolbox menu.
The Pressure Sensor Range item in the Setup menu selects
from the available pressure ranges for the pressure sensor
to be used.
Examples of compatible aftermarket pressure sensors
include the Honeywell PX2 (AA) series and the Measurement
Specialties 7100 series.
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Vent Temperature Monitoring & Limiting
The control has the capability to measure & limit the vent
temperature. The VENT MAX setting defines the operation
of the vent sensor. If the vent temperature exceeds the VENT
MAX, the boiler plant is shut down. The boiler plan will not be
allowed to operate until the vent temperature drops 10°F (6°C)
below the VENT MAX. If OFF is selected, the vent temperature
is only monitored.
Alert Relay
The control has an Alert relay that closes 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 & how to clear the error.
Boiler Alert
If no temperature increase is detected at the boiler supply sensor
within this delay period, the Alert relay will close & the control
will display the NO HEAT error message. To clear the error,
press the CLEAR button while viewing the error message.
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Boiler Plant Operation
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The 284 is able to operate up to four boilers to maintain a boiler
target temperature. Proportional, Integral & Derivative (PID) logic
is used in order to satisfy the boiler target temperature for all
plant configurations with the exception of Dedicated Domestic
Hot Water (DDHW). Proportional (P) logic is used for DDHW.
For proper operation of the boilers, the 284 must be the only
control that determines when a boiler is to fire.
*Important: The boiler operator, or aquastat, remains in the
burner circuit & acts as a secondary upper limit on the boiler
temperature. The boiler aquastat temperature setting must be
adjusted above the 284’s boiler maximum setting in order to
prevent short cycling of the burner.
Boiler Operation
Single Stage On/Off Boiler
Once a boiler is required to operate, the control turns on the
Stage 1 relay. Once the control turns on the Stage 1 relay, it will
display the “Boiler” icon & “100%” under the respective boiler
output status in the display.
Two Stage On/Off Boiler
Once a boiler is required to operate, the control turns on the
Stage 1 relay. Once the Fire Delay time plus the Stage Delay
time has expired, the control can turn on the Stage 2 relay if it
is required. Once the control turns on the Stage 1 relay, it will
display the “Boiler” icon & “50%” under the respective boiler
output status in the display. Once the control turns on the Stage
2 relay, it will display “100%”.
Modulating Boiler
Once a boiler is required to operate, the control outputs an
analog signal corresponding to the Start Modulation setting
& then turns on the Stage 1 relay. Once the Fire Delay time
has expired, the modulating output is adjusted to the Minimum
Modulation setting. The control then holds the modulating output
at the Minimum Modulation until the Minimum Modulation Delay
time has elapsed. The control can then adjust the modulating
output from the Minimum Modulation as required. Once the
control turns on the Stage 1 relay, it will display the “Boiler”
under the respective boiler output status in the display. The
current firing rate is also displayed in the boiler output field.
EMS Boiler
Once a boiler is required to operate, the control outputs an
appropriate analog signal corresponding to the boiler target
temperature & then turns on the Stage 1 relay. Once the control
turns on the Stage 1 relay, it will display the “Boiler” under the
respective boiler output status in the display. The target water
temperature is also displayed in the boiler output field.
Boiler Target Temperature
The Boil TARG temperature is determined by the application
mode & the type of call received. The control displays the
temperature that it is currently trying to maintain at the boiler
supply sensor 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.
Stage Delay
The STG DELAY is the minimum time delay between the firing
of each boiler or boiler stage. After this delay has expired the
control can fire the next boiler or boiler stage if it is required. This
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setting can be adjusted manually or set to an automatic setting.
When the automatic setting is used, the control determines the
best stage delay based on the operation of the system.
Modulation Mode
When using multiple modulating boilers, a selection must be
made regarding the sequencing of the boilers. Two modulation
mode settings are provided considering condensing & noncondensing boiler groups.
Modulation Mode is not available when the Application Mode
is configured for Dedicated Domestic Hot Water (DDHW).
•
MOD COND (Modulation Mode - Modulating, Condensing
Boiler Group)
This setting is applicable for a group at least two modulating,
condensing boilers.
•
MOD NC (Modulation Mode - Modulating, Non-Condensing
Boiler Group)
This setting is applicable for a group of at least two modulating,
non-condensing boilers.
Sequential Modulation (SEQ)
With Sequential Modulation, the control will turn on the fewest
boilers possible to meet the load. The control will bring a
boiler from its Minimum Modulation setting up to its Maximum
Modulation setting before bringing on another boiler. When
another boiler is turned on, the previous boiler will keep its
output at full fire.
100% 60% Off Off
Parallel Modulation (PAR)
With Parallel Modulation, the control will turn on the most
boilers possible to meet the load. The control will bring on
the first boiler at Minimum Modulation & does not increase its
modulation. If more boiler output is required, the second boiler
will turn on at Minimum Modulation & does not increase its
modulation. Additional boilers are turned on at their Minimum
Modulation setting until all boilers are on. If still more boiler
output is required, all boilers are modulated up in parallel until
they reach their Maximum Modulation settings.
40% 40% 40% 40%
Staging Mode Setup
When using multiple two-stage boilers, a selection must be
made regarding the staging order of the boilers. Two staging
modes are provided considering condensing & non-condensing
boiler groups.
•
STG COND (Staging Mode - Two-Stage, Condensing Boiler
Group)
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This setting is applicable for a group of at least two, two-stage
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---
condensing boilers.
STG NC (Staging Mode - Two-Stage Non-Condensing
•
Boiler Group)
This setting is applicable for a group of at least two, two-stage
non-condensing boilers.
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 Group Rotation
The control has two rotation settings including one for the
condensing boiler group & another for the non-condensing
boiler group.
ROT COND (Rotation - Condensing Boiler Group)
•
This setting is applicable for a group of at least two, two-stage
condensing boilers.
ROT NC (Rotation - Non-Condensing Boiler Group)
•
This setting is applicable for a group of at least two, two-stage
non-condensing boilers.
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 & 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 Rotation
setting is set to Off, the firing sequence always begins with
lowest boiler to the highest boiler.
1 2
720 hours
To reset the rotation sequence, clear the Burner Run Time in
the Monitor (#) Menu.
672 hours
Boiler Run Time Monitoring
The running time of each boiler is logged in its respective Monitor
(#) menu. To reset the running time, select the appropriate
BURNER item in the Monitor (#) menu & select CLEAR until
“0” is displayed.
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2 1
672 hours
----------------------
720 hours
Fixed Lead
When the boiler plant includes only one boiler group, either a
condensing or a non-condensing group, a selection must be
made regarding operation of the lead boiler.
ON
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
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.
With a fixed lead rotation, the lead boiler is always turned on
first & turned off first. The Fixed Lead is always applied to the
boiler 1 output.
OFF
The lead boiler is not fixed to operate first in the firing sequence.
It is included in the rotation sequence with the other boilers.
Fixed Last
When the boiler plant includes only one boiler group, either a
condensing or a non-condensing group, a selection must be
made regarding operation of the last boiler.
ON
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 & a single lesser efficient
boiler. The lesser efficient boiler is only desired to be operated
when all other boilers in the plant are on & the load cannot be
satisfied. With a fixed last rotation, the last boiler is the last to
turn on & the first to turn off. The Fixed Last is always applied
to the boiler 4 output.
OFF
The last boiler is not fixed to operate last in the firing sequence.
It is included in the rotation sequence with the other boilers.
Condensing & Non-Condensing Boiler Groups
Operating a boiler plant that contains both condensing (high
initial cost) & non-condensing (lower initial cost) boilers allows
the boiler plant to achieve nearly the same operating efficiencies as operating all condensing boilers but at a much lower
installed cost to the building owner. High system efficiency can
be achieved as long as the condensing boilers are the first to
operate in the firing sequence. During mild weather, the lead
condensing boilers operate at lower boiler temperatures &
achieve their peak boiler efficiencies while the non-condensing
boilers are rarely operated. During very cold weather, the boiler
target temperature is often above the boiler’s condensation
point & the condensing & non-condensing boilers operate
together at roughly the same efficiency level.
When a condensing boiler is operating, it is desirable to operate
the boilers without a boiler minimum temperature being applied
to the boiler target. This allows the condensing boiler to operate
at its maximum efficiency. When a non-condensing boiler is
operating, a boiler minimum temperature should be applied to the
boiler target to prevent damage to the non-condensing boiler’s
heat exchanger from sustained flue gas condensation.
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The 284 supports operation of a condensing & a non-condensing
-------------------
boiler group. A condensing boiler group is created when at least
one boiler is selected to be condensing & a non-condensing
boiler group is created when at least one boiler is selected to
be non-condensing. The condensing boiler group is always
sequenced on first, followed by the non-condensing boiler
group.
Boiler Plant Flow (PLANT FLW)
-------------------
The control supports the option of having all boilers in the plant
to use either a pump or an isolation valve.
Boiler Pump (PUMP)
PUMP is to be selected when each boiler in the plant includes
its own circulator. This is typical of a conventional boiler plant
configuration that includes boilers that are flow sensitive.
PUMP is also to be selected when each boiler in the plant
neither includes a pump nor an isolation valve. This boiler
plant configuration could be used with boilers that are not flow
sensitive. It is expected that the primary pump provides flow
through all boilers, regardless of whether they are on or off.
Boiler Isolation Valve (VALV)
VALVE is to be selected when each boiler in the plant includes
an isolation valve. This boiler plant configuration could be used
with boilers that are not flow sensitive & is typical of systems that
incorporate a variable frequency drive (VFD) with the primary
pump. Systems incorporating variable speed primary pumping
(via a VFD) allow for increased pump electrical energy savings
during milder heating loads.
The purpose of the isolation valve is to isolate the boiler from
plant operation when the boiler is turned off. As a boiler is
isolated, the VFD will adjust the flow rate accordingly. The
isolation valve must include a spring return motor that is of the
normally open / fail open type. As the control does not include a
proof input for proving that the isolation valve is fully open prior
to burner ignition, the motor end switch, if available, should be
wired into the burner’s safety circuit.
Boiler isolation valve operation is dependent on whether the
Heat Call is permanent or intermittent.
Permanent Heat Call (e.g. external Heat Call shorted)
•
As the heating load becomes satisfied & a boiler is required
to be turned off, the boiler will turn off while its isolation valve
remains open for the boiler purge period time. After the boiler
purge time expires, the isolation valve will close. When the last
boiler in the plant turns off, its isolation valve will remain open,
allowing for a flow path of the primary pump.
When there is a subsequent requirement for plant operation
and a boiler is required to be turned on, its isolation valve will
be opened (if not already open) prior to burner ignition. Also,
if applicable, the isolation valve of the last boiler turned off in
the previous cycle will be turned off.
Intermittent Heat Call (e.g. external Heat Call interlocked
•
with space heating thermostat)
When the Heat Call is present, operation is consistent with the
operation defined for a Permanent Heat Call.
When the external Heat Call is removed, the isolation valve
of every boiler will be opened. When the external Heat Call is
re-applied, the control will keep open the valve of the boiler
that is due to be turned on first. The isolation valves of all other
boilers will be closed.
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Outdoor Temperature Reset Operation
-----------------------------------------
---------------------
-------------------------------------
Outdoor Temperature Reset is available by setting the
Application Mode in the Setup Menu to RSET.
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.
Indirect Domestic Hot Water (IDHW) & setpoint operation
are both available during outdoor temperature reset
operation.
Heat Call
-----------------------------------------
A Heat Call is required in order for the control to provide target
water temperature for the space heating system. Once the
control registers a Heat Call, it will display the “Heat” icon
under the Calls in the display. A heat call can be provided
in two ways:
Contact Closure
A dry contact or 24 V (ac) signal is applied across the Heat
Call terminals 5 & 6.
tekmarNet® Device
A tN4 thermostat wired to one of the tN4 Bus terminals.
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 & 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.
Terminal Unit
-------------------------------------
Select the appropriate terminal unit in the Setup 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
& 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 & the surface. This type
of radiant system has a relatively low thermal mass & responds
faster than a high mass system.
Fancoil (COIL)
A fancoil terminal unit or air handling unit (AHU) consisting of
a hydronic heating coil & either a fan or blower. Air is forced
across the coil at a constant velocity by the fan or blower & is
then delivered into the building space.
Boiler Characterized Heating Curve
Terminal
Unit
Outdoor
Design
Boiler
Indoor
Decreasing Outdoor Temperatures
A Watts Water Technologies Company
Boiler
Design
Increasing Water Temperatures
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 & the
room air temperature.
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Radiator (RAD)
--------------------------------------------
----------------------------------
-------------------------------------
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---------------
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 & natural convection.
Baseboard (BASE)
A baseboard terminal unit is similar to a radiator, but has a low
profile & 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, & boiler minimum supply temperatures. The factory
defaults can be changed to better match the installed system.
Locate the Terminal Unit setting in the Setup menu.
Terminal Unit
High Mass Radiant
Low Mass Radiant
Fancoil
Fin-Tube Convector
Radiator
Baseboard
Boil MIN is only available if at least one boiler is set to noncondensing. If all available boilers are set to condensing,
Boil MIN is not available & is hard-coded to OFF.
Boil DSGN Boil MAX *Boil MIN
120°F (49.0°C) 140°F (60.0°C) 140°F (60.0°C)
140°F (60.0°C) 160°F (71°C) 140°F (60.0°C)
190°F (88.0°C) 210°F (99.0°C) 140°F (60.0°C)
180°F (82.0°C) 200°F (93.5°C) 140°F (60.0°C)
160°F (71.0°C) 180°F (82.0°C) 140°F (60.0°C)
150°F (65.5°C) 170°F (76.5°C) 140°F (60.0°C)
Room
The Room setting is the desired room air temperature, according
to the outdoor reset heating curve. 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 (21.0°C), & it can be adjusted for both the occupied &
unoccupied periods.
Outdoor Design
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 & 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
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
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)
Warm Weather Shut Down disables the heating system when the
outdoor air temperature rises above this programmable setting.
When the control enters into WWSD, WWSD is indicated in
the status field. WWSD is only available when the Application
Mode is set to RSET.
While in WWSD, the control will still operate to provide
Indirect Domestic Hot Water or Setpoint operation.
--------------------------------------------
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Setpoint Operation
Setpoint operation is dependant on the application mode
setting.
If the Application Mode is configured for Outdoor Temperature
•
Reset (RSET) or Energy Management System (EMS), the control
provides heat for an additional setpoint load. The control does
respond to a Heat Call from a space heating system.
•
If the Application Mode is configured for Setpoint (SETP), the
control provides heat only for the setpoint load. The control
does not respond to a Heat Call for space heating.
Indirect Domestic Hot Water (IDHW) operation is available
during setpoint operation.
Setpoint Call
A Setpoint Call is required in order for the control to provide
heat to a setpoint load, such as a spa, pool or snowmelt load.
Once the control registers a Setpoint Call, it will display the
“Setpoint” icon under the Calls in the display. A setpoint call
can be provided in two ways:
Contact Closure
A dry contact or 24 V (ac) signal is applied across the Setpoint
Call terminals 9 & 10.
tekmarNet® Setpoint Control with Sensor
A Setpoint Call is provided through the tekmarNet® system.
This can be done through the tN4 Boiler Bus terminals with a
tekmarNet
Boiler Target Temperature During a Setpoint Call
When a Setpoint Call is present, a boiler target is
determined.
•
When using a Contact Closure, the boiler target is set to the
SETP Setpoint setting.
•
When using a tekmarNet® Setpoint Control, the boiler target
is set to the devices Exchange Supply setting.
If there are multiple devices calling for heat, the boiler target
is set to the highest temperature requirement.
------------------------------------
®
setpoint device such as a Setpoint Control 161.
----
Setpoint During UnOccupied
When using a Contact Closure, a second SETP Setpoint setting
is available for the Unoccupied periods.
DIP Switch must be set to Setback to view UnOccupied
items.
During the Away Scene, Setpoint Calls are ignored.
Setpoint Mode
The control has a Setpoint Mode setting that selects whether
or not setpoint heating is operational.
------------------------------------
OFF
Setpoint operation is not provided. All Setpoint Calls are ignored.
If this mode is selected while setpoint operation is underway,
all setpoint operation ceases.
ON
Setpoint heating is provided. All Setpoint Calls are responded to.
Operation is dependant on the Primary Pump During Setpoint
operation setting.
Primary Pump During Setpoint
This setting selects whether or not primary pump operation is
required during setpoint heating.
------------------
OFF
The primary pump does not turn on during setpoint heating. It
is assumed that the setpoint load pump will provide adequate
flow through the setpoint load & the boiler system loop.
Setpoint
Primary
ON
The primary pump turns on during setpoint heating.
Setpoint
Primary
Setpoint Priority
This setting selects whether or not priority of setpoint over
space heating is required. Setpoint priority stops or limits the
delivery of heat to the space heating system while the setpoint
load calls for heat. This allows for quick recovery of the load.
OFF
Setpoint priority is not provided. The primary pump can operate
when a Heat Call is present. Heating zones are unaffected by
setpoint heating.
----------------------------------
ON
Setpoint priority is provided & is dependant on the type of
space heating zones & whether or not the primary pump is
required to operate during setpoint heating.
For non-tN4 space heating, the primary pump shuts off to
provide priority. If the primary pump is required to operate for
setpoint heating, priority requires the use of an external relay
to force the heating zones off.
For tN4 space heating, the primary pump can operate when a
Heat Call is present. If the boilers are unable to maintain the
boiler target temperature, the tN4 zones are sequentially shut
off using tN4 communication to provide priority.
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Priority Override
---------------------------------
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------------------------------
-----------------------------------------
---------------------------------------
Priority Override applies when Setpoint Priority is set to ON. It
prevents the building from cooling off too much or the possibility
of a potential freeze up during 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 the Indoor
Design temperature, 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 Setup menu.
The priority timer does not start timing until priority is selected
& both a Setpoint Call & a Heat Call exist together. Once the
allowed time for priority has elapsed, the control overrides the
setpoint priority & resumes space heating.
---------------------------------
Energy Management System (EMS) Operation
Conditional Setpoint Priority
If the boiler supply temperature is maintained at or above the
required temperature during setpoint heating, this indicates
that the boilers have enough capacity for setpoint & possibly
space heating as well. As long as the boiler supply temperature is maintained near the target, setpoint & heating occurs
simultaneously.
Setpoint Post Purge
After a Setpoint Call from a tN4 device is removed, the control
can perform a post purge. The control shuts off the boilers &
continues to operate, if applicable, the primary pump. 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 Heat Call is detected.
2. The boiler supply drops 20°F (11.0°C) below the setpoint
target temperature.
3. Two minutes elapse.
------------------------------
---------------------
The control can accept an external DC signal from an Energy
Management System (EMS). The control converts the DC
signal into the appropriate boiler target temperature for the
space heating system.
EMS is available by setting the APP MODE in the Setup Menu
to EMS.
Indirect Domestic Hot Water (IDHW) & setpoint are both
available during EMS operation.
Heat Call
A Heat Call is required in order for the control to provide a
target water temperature for the space heating system. Once
the control registers a Heat Call, it will display the “Heat” icon
under the Calls in the display.
A Heat Call is provided by:
Input Signal
An external signal is generated by applying a voltage between
0 V (dc) & 10 V (dc) across the EMS (+) In & Com (-) terminals
(16 & 19). Voltages that exceed 10 V (dc) will still be considered
a 10 V (dc) signal.
If the EMS signal goes below the minimum voltage, the “Heat”
icon under the Calls in the display is turned off. The boiler target
temperature is displayed as “– – –” to indicate that there is no
longer a call for heating.
External Heat Call terminals are not operational.
EMS Signal
The control can accept either a 0-10 V (dc) signal or a 2-10 V
(dc) signal. The EMS SGNL 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
(10.0°C). An input voltage of 10 V (dc) corresponds to a boiler
target temperature of 210°F (99.0°C). As the voltage varies
between 1 V (dc) & 10 V (dc) the boiler target temperature varies
linearly between 50°F (10.0°C) & 210°F (99.0°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 EMS (+) In & Com
(-) terminals (16 & 19).
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
(10.0°C). An input voltage of 10 V (dc) corresponds to a boiler
target temperature of 210°F (99.0°C). As the voltage varies
between 2 V (dc) & 10 V (dc) the boiler target temperature varies
linearly between 50°F (10.0°C) & 210°F (99.0°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 EMS (+) In & Com
(-) terminals (16 & 19).
CONVERSION TABLE 0 - 10
0 - 20 mA* 0 - 10 V (dc) Boiler Target
0 0 – – – (OFF)
2 1 50°F (10.0°C)
4 2 68°F (20.0°C)
6 3 86°F (30.0°C)
8 4 103°F (39.5°C)
10 5 121°F (49.5°C)
12 6 139°F (59.5°C)
14 7 157°F (69.5°C)
16 8 174°F (79.0°C)
18 9 192°F (89.0°C)
20 10 210°F (99.0°C)
*Requires 500 Resistor in Parallel
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CONVERSION TABLE 2 - 10
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---------------------------------
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4 - 20 mA* 2 - 10 V (dc) Boiler Target
0 0 – – – (OFF)
4 2 50°F (10.0°C)
6 3 70°F (21.0°C)
8 4 90°F (32.0°C)
10 5 110°F (43.5°C)
12 6 130°F (54.5°C)
14 7 150°F (65.5°C)
16 8 170°F (76.5°C)
18 9 190°F (88.0°C)
20 10 210°F (99.0°C)
*Requires 500 Resistor in Parallel
EMS Offset
For external input operation, the boiler target (determined
from the external input signal) may be fine tuned. The EMS
OFFST setting is used to provide the fine tuning. The setting
may be adjusted ±10°F (±5.5°C). When set to 0°F (0.0°C), if
the temperature determined from the external signal is 140°F
(60.0°C), the boiler target will be 140°F (60.0°C). When set
to +5°F (+3.0°C) & with the same external signal represents
140°F (60.0°C), the boiler target will be 145°F (63.0°C).
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)
The minimum & maximum settings also apply for external input
operation. For example, if a boiler minimum of 140°F (60.0°C) is
set & the external signal received represents 80°F (27.0°C), the
boiler target will be 140°F (60.0°C). MIN will also be displayed
in the status field to indicate that a limiting condition is in effect.
This also applies for the MAX limit.
Indirect Domestic Hot Water (IDHW) Operation
IDHW operation is applicable during the following application
modes: outdoor temperature reset, fixed setpoint & EMS.
DHW Call
A DHW Call is required in order for the control to provide heat
to an indirect DHW tank. Once the control registers a DHW
Call, it will display the “DHW” icon under Calls in the display.
A DHW Call can be provided in three ways:
DHW Tank Aquastat
If a DHW Tank Aquastat (mechanical switch) is used to apply
a DHW Call, the tank is heated to the aquastat temperature
setting. A dry contact or 24 V (ac) signal is applied across the
IDHW Call terminals 7 & 8.
IDHW Sensor must be set to Off.
DHW Sensor
A DHW Tank Sensor provides superior temperature control
of the tank compared to an aquastat. The control can register
a DHW Call when a DHW Sensor is wired to terminals 21
& 22. Once the DHW Sensor temperature drops 1/2 of the
IDHW Differential setting below the iDHW Setpoint, the control
registers a DHW Call.
The IDHW Sensor must be set to On. There cannot be
an external IDHW Call when using a DHW sensor.
tekmarNet® Setpoint Control with Sensor
A DHW Call is provided through the tekmarNet® system. This can
be done through the tN4 Boiler Bus terminals with a tekmarNet®
setpoint device such as a Setpoint Control 161.
DHW Differential
Due to large differences between the heating load & the DHW
load, a separate DHW differential should be used whenever a
DHW Call is present. This will improve staging & boiler cycling.
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When using a DHW Sensor, a DHW Call is registered when the
temperature at the DHW sensor drops the IDHW DIFF setting
below the IDHW Setpoint setting. The DHW Call is satisfied
once the temperature at the DHW Sensor rises to the IDHW
Setpoint setting.
DHW Target
ON
Boiler Target Temperature during a DHW Call
OFF
IDHW
Differential
------
When a DHW Call is present, a boiler target is determined.
When using a DHW Tank Aquastat, the boiler target is set
•
to the IDHW Exchange setting.
When using a DHW Tank Sensor, the boiler target is fixed
•
at the IDHW Setpoint setting plus 40°F (22.0°C).
When using a tekmarNet® Setpoint Control, the boiler target
•
is set to the devices Exchange Supply setting.
If there are multiple devices calling for heat, the boiler target
is set to the highest temperature requirement.
IDHW During UnOccupied
------------------------
When using a DHW Tank Aquastat, a second IDHW Exchange
setting is available for the UnOccupied or Sleep period.
When using a DHW Sensor, a second IDHW Setpoint 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 Calls are ignored.
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IDHW Mode
-------------------------------------
----------------------------------
---------------------------------------
-------------------------------------
-------------------------------------
The control has a IDHW MODE setting that selects whether
or not indirect DHW operation is active.
OFF
IDHW operation is inactive. All DHW Calls are ignored. If this
mode is selected while DHW operation is underway, all DHW
operation ceases.
ON
IDHW operation is active. All DHW Calls are responded to.
IDHW Location
----------------------------------
The control has a IDHW Location setting that selects where
the indirect DHW tank is located in the system. This setting
determines the operating sensor & affects pump operation.
NEAR
The indirect DHW tank is piped in parallel within the near boiler
piping of boiler 4. When a valid DHW Call is present, the IDHW
Pump relay turns on & boiler pump 4 turns off. The control uses
the boiler 4 outlet sensor as the operating sensor in order to
measure the boiler supply temperature supplied to the indirect
DHW tank. There are two boiler target temperatures. One for
the space heating system (Boil TARG) & one for the indirect
DHW system (IDHW TARG).
Primary Pump During IDHW
---------------------------------------
The control has a Primary Pump during IDHW setting that
selects whether or not the primary pump is required during
indirect DHW operation.
OFF
The primary pump does not turn on during indirect DHW operation. This would be typical of an indirect DHW tank piped in
parallel in the boiler system loop. It is assumed that the DHW
pump will provide adequate flow through the indirect DHW
heat exchanger & the boiler system loop.
DHW
Pump
ON
Primary
Pump OFF
ON
The primary pump turns on during indirect DHW operation.
This would be typical of an indirect DHW tank piped in
primary/secondary in the boiler system loop.
Near Boiler
All boilers are used for space heating requirements.
•
Boiler 4 is used for indirect DHW when there is a DHW
•
Call.
•
The dedicated indirect DHW boiler is always boiler 4, even
if there are less than four boilers.
If boiler 4 is disabled & NEAR is selected for the IDHW Location,
•
the dedicated indirect DHW boiler 4 will not operate.
Boil
The indirect DHW tank is piped in the boiler system loop. When
a valid DHW Call is present, the IDHW Pump relay turns on.
Piped off
boiler
system loop
DHW
Pump
ON
Primary
Pump ON
IDHW Priority
-------------------------------------
The control has a IDHW Priority setting that selects whether or
not priority of indirect DHW is required over the space heating
system. Indirect DHW priority stops or limits the delivery of
heat to the space heating system while the indirect DHW tank
calls for heat. This allows for quick recovery of the indirect
DHW tank.
OFF
IDHW priority is not provided. The primary pump can operate
when a Heat Call is present. Heating zones are unaffected by
indirect DHW operation.
ON
IDHW priority is provided & is dependant on the type of space
heating zones & whether or not the primary is required to
operate during IDHW operation.
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For non-tN4 space heating, the primary pump shuts off to
---------------------------------
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---------------------------------
-------------------------------
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-------------------------
provide priority. If the primary pump is required to operate for
IDHW, priority requires the use of an external relay to force
the heating zones off.
For tN4 space heating, the primary pump can operate when a
Heat Call is present. If the boilers are unable to maintain the
boiler target temperature, the tN4 zones are sequentially shut
off using tN4 communication to provide priority.
Priority Override
Priority override applies when IDHW Priority is set to ON &
prevents the building from cooling off too much or the possibility
of a potential freeze up during IDHW priority.
When set to auto, the priority time is calculated based on outdoor
temperature. At or below the design outdoor temperature, 15
minutes is allowed for IDHW priority. At or above the design
indoor temperature, 2 hours is allowed for IDHW priority. The
time allowed for IDHW priority varies linearly between the
above two points. There is a manual setting also available in
the Setup menu.
The priority timer does not start timing until priority is selected
& both a DHW Call & a Heat Call exist together. Once the
allowed time for priority has elapsed, the control overrides the
DHW priority & resumes space heating.
---------------------------------
Automatic Priority Override
2 hours
15 mins
Indoor Design
Temperature
Conditional IDHW Priority
If the boiler supply temperature is maintained at or above the
required temperature during IDHW operation, this indicates that
the boilers have enough capacity for IDHW & possibly heating
as well. As long as the boiler supply temperature is maintained
near the target, IDHW & heating occurs simultaneously.
IDHW Post Purge
After the DHW Call is removed, the control performs a purge.
The control shuts off the boilers & continues to operate the
IDHW Pump & 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 Heat Call is detected.
2. The boiler supply drops 20°F (11.0°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.
---------------------------------
Outdoor Design
Temperature
------------------------
IDHW Mixing Purge
After IDHW 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 Call with priority, the control shuts off the
boiler & continues to operate the IDHW 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 & temper the
boiler return water.
IDHW 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 Call.
This may result in damage to the low temperature heating
system.
The control is capable of providing IDHW 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:
All available boilers are set to condensing.
•
IDHW Location set to Boil.
•
IDHW Priority set to ON.
•
tN4 present (IF Primary Pump during IDHW operation is
•
set to ON)
On a DHW Call, the control provides IDHW 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, or selectable
time, as described in the IDHW Priority Override section.
However, if the DHW Call is not satisfied within the allotted
time, the boiler shuts off & the heat of the boiler is purged
into the DHW tank. A IDHW mixing purge occurs in order to
reduce the boiler water temperature & once the boiler supply
temperature is sufficiently reduced, the IDHW 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, & if the DHW Call is still present, the
control shuts off the heating system & provides heat to the
DHW tank once again.
IDHW Boil COUNT IDHW
Selects the number of boilers to be used for IDHW operation.
This applies when only there is a requirement for IDHW. All
available boilers are allowed to operate if there is both a
requirement for space heating & IDHW.
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Dedicated Domestic Hot Water (DDHW) Operation
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The control can operate to provide heat for a Dedicated
Domestic Hot Water (DDHW) system.
DDHW heating is available by setting the Application Mode in
the Setup Menu to DDHW.
DHW Call
A DHW Call is required in order for the control to provide heat
to a dedicated DHW tank. Once the control registers a DHW
Call, it will display the “DHW” icon under Calls in the display.
This can be done by:
DHW Sensor
The control can register a DHW Call when a DHW Sensor is
wired to terminals 21 & 22. Once the DHW Sensor temperature
drops 1/2 of the DDHW Differential setting below the DDHW
Setpoint, the control registers a DHW Call.
-----------------------------------------
DDHW Differential
A DHW Call is registered when the temperature at the DHW
sensor drops the DDHW DIFF setting below the DDHW Setpoint
setting. The DHW Call is satisfied once the temperature at the
DHW Sensor rises to the DDHW Setpoint setting.
DHW Target
ON
Boiler Target Temperature During a DDHW Call
When a DHW Call is present, a boiler target is determined. The
boiler target is set to the DDHW Setpoint setting.
DDHW During UnOccupied
A second DDHW Setpoint setting is available for the
UnOccupied periods.
DIP Switch must be set to Setback to view UnOccupied
items.
During the Away Scene, DHW Calls are ignored.
--------------------------------
OFF
IDHW
Differential
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-----------------------
Building Automation System (BAS)
The control can communicate with a Building Automation System
(BAS) to provide remote monitoring & adjustment capability.
BAS Mode
There are two modes of BAS communication that define the
interaction between the BAS & the control. The level of interaction is determined by the Application Mode setting.
Refer to the BAS Integration Manual 284_B for more information
including a listing of the read / write parameters.
Monitor
Monitor mode is available when the Application Mode is set
to either Outdoor Temperature Reset, Setpoint, Dedicated
Domestic Hot Water (DDHW) or Energy Management System
(EMS).
With Monitor mode, the control allows for viewing & adjustment
capability of select items within the various menus.
Temp erature
Temperature mode is available when the Application Mode is
set to Building Automation System (BAS).
With Temperature mode, the control operates to maintain
the setpoint temperature provided over the BAS network. In
order for the control to be able to operate to maintain the BAS
Setpoint, the BAS must also write a Setpoint Call command
over the BAS network.
----------------------------------------
If primary pump operation is desired, the BAS must write a
BAS Primary Pump command over the BAS network.
If indirect DHW pump operation is desired, the BAS must write
a BAS IDHW Pump command over the BAS network.
BAS Type
The control supports Modbus® & BACnet® IP communications.
Selection is made through BAS TYPE item in the BAS menu.
If the control is not being connected to a BAS network, select
NONE.
Network Configuration Settings in BAS Menu
Refer to the BAS menu section of this brochure for a listing of
all the BAS network configuration settings.
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Pump Operation
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Primary Pump Operation
The control includes two primary pump outputs with capability
for sequencing. There is pump enable setting for each primary
pump in the Setup menu. When both primary pumps are set
to Auto, primary pump sequencing is activated. Primary pump
1 & 2 are operated in stand-by mode when pump sequencing
is activated.
The running times of the primary pumps are logged in the
Monitor Menu. To reset these values back to zero, select
“Clear” while viewing this item.
Operation of the primary pump(s) is determined from the
Application Mode & the presence of an appropriate call.
Application Mode: Outdoor Temperature Reset (RSET)
Heat Call from Contact Closure.
•
Heat Call from tN4 Device & that zone’s thermostat has H1
•
Pump set to On. tN4 thermostats also include a thermal
actuator setting which can delay the primary pump for 3
minutes to allow thermal actuators to open.
Setpoint Call from Contact Closure & Primary Pump during
•
Setpoint operation set to ON.
DHW Call & the Primary Pump during IDHW operation set
•
to ON.
Application Mode: Setpoint (SETP)
Setpoint Call from Contact Closure & Primary Pump during
•
Setpoint operation set to ON.
•
DHW Call & the Primary Pump during IDHW operation set
to ON.
Application Mode: Energy Management System (EMS)
•
Heat Call from Analog Input Signal.
•
DHW Call & the Primary Pump during IDHW operation set
to ON.
•
Setpoint Call from Contact Closure & Primary Pump during
Setpoint operation set to ON.
Application Mode: Building Automation System (BAS)
•
BAS Setpoint Pump Call.
Flow Proof Call
The control includes a flow proof call in order to prove flow
once a primary pump has turned on. In order for boiler plant
operation to commence, the proof call must be present. A flow
proof call is required at all times during pump operation.
Once a primary pump contact is turned on, a flow proof call
must be present before the flow proof delay has expired.
The flow proof call feature is enabled by setting the DIP switch
to the External Flow Proof position.
The flow proof call feature can only be used when the
control is configured to operate the primary pump for
all loads.
If there are multiple loads (e.g. Heat Call and DHW Call)
and the primary pump is disabled for DHW operation, then
the control cannot provide flow proving and the feature
must be disabled. In this case, the flow proof feature must
be obtained through another control such as the Pump
Sequencer 132.
-----------------------------------
-------------------------
A flow proof call can be provided in two ways:
Contact Closure
A dry contact or 24 V (ac) signal is applied across the Flow
Proof Call terminals 1 & 2.
A contact closure can come from a flow switch, pressure
differential switch, current sensing or power sensing device.
∆P Pressure Differential Switch
FS Flow Switch
KW Power Sensing Device
Amp Current Sensing Device
Analog Flow Sensor
A 4-20 mA style flow sensor can be used to both monitor &
prove flow. The Flow Sensor item in the Setup Menu must be
set to ON to enable the flow sensor to provide monitoring. The
Flow Rate 4 mA and Flow Rate 20 mA items in the Setup Menu
configure the flow range for the flow sensor being used.
To enable the flow proof feature, the Flow Proof item in the Setup
Menu must be set to a flow percentage. The flow percentage is
the percentage of full flow (dependant on the configured flow
range) that must be achieved within the flow proof delay time
to prove flow. If the flow sensor is not required to prove flow,
the Flow Proof item must be set to OFF.
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 an appropriate Call is registered, the lead pump is
•
activated, & 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 & the control waits again for the flow
to establish within the flow proof delay time.
If no flow is established with the lag pump, the control
•
will make a second attempt to prove flow with the pumps,
starting with the lead pump. If flow cannot be proved after
the second attempts, the control stops operation until the
error is cleared. Verify that the pumps & flow proof device
are working correctly before clearing the error.
If the lead pump establishes flow, & fails during operation,
•
the lag pump is activated.
If at any time, one or both pumps fail to prove flow, an error
•
message is displayed.
Normal Operation
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ON
OFF
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