Slant/Fin EM-10 Service Manual

MODEL EM-10
ELECTRIC BOILER CONTROL
Publication No. EM-40-SM
Printed in U.S.A. 914
Part No. 792840000
SERVICE MANUAL
This brochure is organized into three main sections. They are: 1) Sequence of Operation, 2) Installation, and
The Control Settings section of this brochure describes the various items that are adjusted and displayed by the control. The control functions of each adjustable item are described in the Sequence of Operation.
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How to Use the Data Brochure
Table of Contents
User Interface ..................................................................2
Display and Symbol Description ......................................3
Sequence of Operation ....................................................4
Section A:General ............................................................4
Section B: Setpoint Operation..........................................9
Section C: Dedicated DHW Operation ............................9
Section D: Outdoor Reset Operation ............................10
Section E: External Temperature Target Input................10
Section F: External Direct Drive Operation....................11
Installation ......................................................................12
Testing ............................................................................13
Control Settings..............................................................15
DIP Switch Settings........................................................15
Mode 1 and 2 - Two Setpoint Operation ........................16
View Menu......................................................................16
Adjust Menu ..................................................................17
Mode 3 - Dedicated DHW with Parallel Piping ..............19
View Menu......................................................................19
Adjust Menu ..................................................................20
Mode 4 and 5 - Outdoor Reset / Setpoint Operation ....22
View Menu......................................................................23
Default Settings ........................................................24-26
Adjust Menu ..................................................................24
Mode 6 and 7 - External Target / Setpoint Operation ....27
View Menu......................................................................28
Adjust Menu ..................................................................29
Mode 8 - External Direct Drive Operation......................31
View Menu......................................................................31
Adjust Menu ..................................................................32
Error Messages..............................................................33
Reload Factory Defaults ................................................34
Specifications ................................................................36
User Interface
The BTC uses a Liquid Crystal Display (LCD) as a method of supplying information. You use the LCD in order to setup and monitor the operation of your system. The BTC uses three push buttons (Item, p,q) for selecting and adjusting settings. As you program your control, record your settings in the settings column of the Adjust menu. The table is found in the second half of this brochure.
MENU
All of the items displayed by the control are organized into two menus:
1) View
2) Adjust These menus are listed on the upper right hand side of the
display (Menu Field). The default menu for the BTC is the View menu. While in the View menu, the VIEW segment is displayed.
To select the Adjust menu, press and hold simultaneously all three buttons (Item, p,q) for 1 second.
The display then advances to the Adjust menu and the ADJUST segment is turned on in the display. The display will automatically revert back to the View menu after 20 seconds of keypad inactivity. Once in a menu, there will be a group of items that can be viewed within that menu.
ITEM
The abbreviated name of the selected item will be displayed in the item field of the display. To view the next available item, press and release the Item button. Once you have reached the last available item in a menu, pressing and releasing the Item button will return the display to the first item in the selected menu.
ADJUST
To make an adjustment to a setting in the control, begin by selecting the Adjust menu by pressing and holding simultaneously all three buttons. Then select the desired item using the Item button. Finally, use the p or q button to make the adjustment.
STATUS FIELD
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. Symbols in the status field are only visible when the View menu is selected.
Item
Item
Item
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Item
Number Field
Displays the current value of the selected item
Item Field
Displays the current
item selected.
Menu Field
Displays the current menu
Buttons
Selects Menus, Items and adjusts settings
Status Field
Displays the current status of the control’s inputs, outputs and operation
Display
Symbol Description
BOILER PUMP
Displays when the boiler pump is in operation.
BURNER
Displays when stage 1, 2, 3, or 4 contact is on.
WWSD
Displays when the control is in Warm Weather Shut Down.
DEMAND 1
Displays when a call for heat on demand 1 is present.
DEMAND 2
Displays when a call for heat on demand 2 is present.
ERROR
Displays when an error message is present.
POINTERS
Displays operation as indicated by the text.
°F,°C
°F or°C
Displays the temperature units.
POWERING UP THE CONTROL
When the control is powered up, the control turns on all segments in the display for 2 seconds. Next, the software version is displayed for 2 seconds. Last, the control enters into the normal operating mode.
DISPLAY BACKLIGHT
The control’s display has a backlight that is permanently on while the control is powered.
PIPING
The boiler can be piped in parallel or in primary/secondary to the system. The type of piping chosen affects the location of the control’s operating temperature sensor. The control can either use the boiler outlet sensor or the boiler supply sensor.
PARALLEL PIPING
In parallel piping applications, the boiler outlet temperature is typically the same as that delivered to the system. Therefore the operating temperature sensor is the boiler outlet sensor.
PRIMARY/SECONDARY PIPING
In primary/secondary applications, the boiler outlet temperature (primary loop) is typically hotter than the system supply temperature (secondary loop). This occurs when the system supply pipe has a larger flow rate than the boiler outlet pipe. Therefore, the control requires an additional sensor (boiler supply) to measure the temperature delivered out to the system. The operating temperature sensor is the boiler supply sensor.
MODES OF OPERATION (MODE)
The control allows for seven modes of operation in order to define the control operation and piping arrangement used. The piping arrangement can be categorized into parallel and primary / secondary. The mode of operation is selected using the MODE item in the Adjust menu. The temperature being controlled out to the heating system is measured by the operating sensor.
The piping arrangement determines which sensor the control uses as the operating sensor. The operating sensor is either the boiler outlet sensor or the boiler supply sensor.
MODE 1 (Two Setpoints with Parallel Piping) Mode 1 is designed for setpoint operation using parallel piping. The heat demand is available to activate a setpoint for space heating systems. The setpoint demand is available to activate a second setpoint for heating an indirect domestic hot water tank.
Once a heat demand is present, the control stages the boiler to maintain the boiler target 1 at the boiler outlet sensor. Once a setpoint demand is present, the control stages the boiler to maintain the boiler target 2 at the boiler outlet sensor. If both demands are present, the control operates at the higher of the two targets. Refer to section B for a description of setpoint operation.
MODE 2 (Two Setpoints with Primary/Secondary Piping) Mode 2 is designed for setpoint operation using primary / secondary piping. A heat demand is available to activate a setpoint for space heating systems. A setpoint demand is available to activate a second setpoint for heating an indirect domestic hot water tank.
Once a heat demand is present, the control stages the boiler to maintain the boiler target 1 at the boiler supply sensor. Once a setpoint demand is present, the control stages the boiler to maintain the boiler target 2 at the boiler supply sensor. If both demands are present, the control operates at the higher of the two targets. Refer to section B for a description of setpoint operation.
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Section A: General
Factory Installed Boiler Outlet Sensor
Boiler Inlet Sensor (Included)
Factory Installed Boiler Outlet Sensor
Secondary Piping Sensor (Included)
Boiler Inlet Sensor (Included)
BTC
Mode 1
Relay
Factory Installed Boiler Outlet Sensor
Boiler Inlet Sensor (Included)
BTC
Mode 2
Zone Box
Relay
Factory Installed Boiler Outlet Sensor
Boiler Inlet Sensor (Optional)
Secondary Piping Sensor (Included)
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MODE 3
(Dedicated Domestic Hot Water Tank) Mode 3 is designed for heating a dedicated domestic hot water tank using parallel piping. A tank sensor creates an internal heat demand in the control. Once an internal heat demand is present, the control stages the boiler to maintain the boiler target temperature at the boiler outlet sensor. Refer to section C for a description of dedicated domestic hot water tank operation.
MODE 4 (Outdoor Reset and Setpoint with Parallel Piping) Mode 4 is designed for outdoor reset and setpoint oper­ation using parallel piping. The heat demand is available to provide outdoor reset for space heating systems. The setpoint can be used to heat an indirect domestic hot water tank.
Once a heat demand is present, the control stages the boiler to maintain the calculated outdoor reset target at the boiler outlet sensor. Refer to section D for a descrip­tion of outdoor reset operation.
Once a setpoint demand is present, the control stages the boiler to maintain the boiler target at the boiler out­let sensor. If both demands are present at the same time, the control targets the higher of the two require­ments. Refer to section B for a description of setpoint operation.
MODE 5 (Outdoor Reset and Setpoint with Primary/
Secondary Piping) Mode 5 is designed for outdoor reset and setpoint operation using primary / secondary piping. The heat demand is available to provide outdoor reset for space heating systems. The setpoint demand can be used to heat an indirect domestic hot water tank.
Once a heat demand is present, the control stages the boiler to maintain the calculated outdoor reset target at the boiler supply sensor. Refer to section D for a description of outdoor reset operation.
Once a setpoint demand is present, the control stages the boiler to maintain the boiler target at the boiler supply sensor. If both demands are present at the same time, the control targets the higher of the two requirements. Refer to section B for a description of setpoint operation.
MODE 6 (External Target Temperature Input and Setpoint with Parallel Piping) Mode 6 is designed for an external input signal and setpoint with parallel piping. The external input signal can be provided from a BMS, an EMS, or a tekmar tN4 System Control for space heating. The setpoint can be used to heat an indirect domestic hot water tank.
The external input signal creates an internal demand and changes the boiler target according to a linear scale. The control stages the boiler to maintain the boiler target at the boiler outlet sensor. Refer to section E for a description of external target temperature operation.
Once a setpoint demand is present, the control stages the boiler to maintain the boiler target at the boiler outlet sensor. If both an external input signal and a setpoint demand are present at the same time, the control targets the higher of the two requirements. Refer to section B for a description of setpoint operation.
BTC
Mode 3
DHW Tank Sensor
Factory Installed Boiler Outlet Sensor
Boiler Inlet Sensor (Included)
BTC
Mode 5
Outdoor Sensor
Relay
Factory Installed Boiler Outlet Sensor
Secondary Piping Sensor (Included)
Boiler Inlet Sensor (Optional)
BTC
Mode 4
Relay
Outdoor Sensor
Factory Installed Boiler Outlet Sensor
Boiler Inlet Sensor (Included)
BTC
Mode 6
EMS
0-10 V (dc)
Relay
Boiler Inlet Sensor (Included)
Factory Installed Boiler Outlet Sensor
MODE 7 (External Target Temperature Input and Setpoint with Primary/Secondary Piping) Mode 7 is designed for an external input signal and setpoint with primary/secondary piping. The external input signal can be provided from a BMS, an EMS, or a tekmar tN4 System Control for space heating. The setpoint can be used to heat an indirect domestic hot water tank.
The external input signal creates an internal demand and changes the boiler target according to a linear scale. The control stages the boiler to maintain the boiler target at the boiler supply sensor. Refer to section E for a description of external target temperature operation.
Once a setpoint demand is present, the control stages the boiler to maintain the boiler target at the boiler supply sensor. If both an external input signal and a setpoint demand are present at the same time, the control targets the higher of the two requirements. Refer to section B for a description of setpoint operation.
MODE 8 (External Direct Drive Operation) Mode 8 is designed for an external input signal to directly control the staging rate of the boiler with either parallel or primary / secondary piping. The heat demand and setpoint demand inputs are disabled. Refer to section F for a description of external target temperature operation.
STAGING MODE (STGMODE) The control can operate up to four stages in order to
supply the required target temperature. The method of staging used by the control is either P (proportional) or PID (Proportional & Integral & Derivative), and is selected using the STGMODE item in the Adjust menu.
Proportional & Integral & Derivative (PID)
PID staging allows the control to determine when the next stage is required to turn on. After a stage is turned on in the firing sequence, the control waits a minimum amount of time (Stage Delay) before turning on the next stage. After the minimum time delay between stages has expired, the control examines the control error to determine when the next stage is to fire. The control error is determined using PID logic.
Proportional logic compares the actual operating sensor temperature to the boiler target temperature. The colder the temperature, the sooner the next stage is turned on. Integral logic compares the actual operating sensor temperature to the boiler target temperature over a period of time.
Derivative logic determines how fast or slow the operating sensor temperature is changing. If the temperature is increasing slowly, the next stage is turned on sooner. If the temperature is increasing quickly, the next stage is turned on later, if at all.
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BTC
Mode 7
0-10 V (dc)
tN4 System
Control
Relay
Factory Installed Boiler Outlet Sensor
Boiler Inlet Sensor (Optional)
Secondary Piping Sensor (Included)
External Control Sensor
175 ° F 170°F
180°F Setpoint
Proportional Staging
185°F
190°F
155°F 150°F 145°F 140°F
160°F
165°F
Stage 4
Stage 3
Stage 2
Stage 1
water
temperature
droop
wa te r
temperature
droop
water
temperature
droop
175 ° F 170°F
180°F Setpoint
P.I.D. Staging
very little temperature droop
185°F
165°F
Stage 4 Stage 3 Stage 2 Stage 1
P.I.D. = Proportional + Integral + Derivative
BTC
Mode 8
External
Control
BTC
0-10 V (dc)
Direct Drive
Boiler Supply Sensor
Boiler Inlet Sensor (Included)
External Control Sensor
Factory Installed Boiler Outlet Sensor
Factory Installed Boiler Outlet Sensor
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STAGE DELAY (STG DLY)
The stage delay is the minimum time between firing first to second stage, second to third stage, and third to fourth stage and is determined by the Stage Delay setting. It can be manually set, or it can be set to automatic in which the boiler mass determines the stage delay time.
BOILER MASS (BOIL MASS)
The boiler mass setting allows the installer to adjust the control to the thermal mass of different types of heat sources used. The boiler mass setting automatically determines the stage delay on, stage delay off, minimum on time and minimum off time of the stages. A higher thermal mass setting provides slower staging, while a lower thermal mass provides faster staging.
Proportional (P)
Proportional staging, also known as step staging, is based on manually adjusted settings that determine when the next stage is required to turn on. These manual settings are based on temperature and time. The interstage differential sets the temperature drop at which the next stage turns on. However, in order for a stage to fire, the interstage delay on and minimum off times must first elapse.
Interstage Differential (STG DIFF)
The interstage differential is the temperature drop at which the next stage will turn on. Once a stage turns on, the next stage cannot turn on until the temperature drops the interstage differential below the temperature at which the previous stage turned on. The interstage differential is adjustable through the STG DIFF setting in the Adjust menu.
Interstage On Delay (ON DLY)
The interstage on delay is the amount of time that must elapse before turning on the next stage. Once a stage turns on, the next stage cannot turn on until the interstage delay on time elapses. The interstage on delay is adjustable through the ON DLY setting in the Adjust menu.
Interstage Off Delay (OFF DLY)
The interstage off delay is the amount of time that must elapse before turning off the next stage. Once a stage turns off, the next stage cannot turn off until the interstage delay off time elapses. The interstage off delay is adjustable through the OFF DLY setting in the Adjust menu.
Minimum On Time (MIN ON)
The minimum on time is the minimum amount of time that a stage must be on before it is allowed to turn off. Once a stage turns on, it cannot turn off until a minimum on time elapses. The minimum on time is adjustable through the MIN ON setting in the Adjust menu.
Minimum Off Time (MIN OFF)
The minimum off time is the minimum amount of time that a stage must be off before it is allowed to turn on. Once a stage turns off, it cannot turn on until a minimum off time elapses. The minimum off time is adjustable through the MIN OFF setting in the Adjust menu.
BOILER DIFFERENTIAL (DIFF)
A heat source must be operated with a differential in order to reduce short cycling. The boiler differential is divided around the boiler target temperature. The first stage contact will close once the water temperature at the operating sensor is 1/2 of the differential setting below the boiler target temperature, and will open once the water temperature at the operating sensor is 1/2 of the differential setting above the boiler target temperature.
Manual Differential
The differential can be manually set using the DIFF setting in the Adjust menu.
Auto Differential
Auto differential is only available when using PID staging.
If the Auto Differential is selected, the control automatically determines the best differential as the load changes, thereby improving efficiency. During light loads, the differential is increased to allow longer on and off times to reduce the potential for short cycling. During large loads, the differential is narrowed thereby improving comfort in heating spaces by reducing temperature swing.
Proportional Staging
A Minimum On Time B Minimum Off Time
C Interstage On Delay D Interstage Off Delay
A B C D
Fixed Differential
Differential
Desire d Temperature
Desired Temperature
Increasing
Temperature
Increasing Time
ON ON
OFF
OFF
Automatic Differential
Differential
Low Heat Load
ON
ON
OFF
OFF
Differential
High Heat Load
ON
ON
FFOFFO
OUTDR DSGN
Boil DSGN
Boil START
OUTDR START
FIRE DELAY (Burner symbol DLY) Does NOT apply to electric boiler operation.
The Fire Delay is the delay time that may occur between the time that the control closes the Stage 1 contact and when the burner fires. This delay is usually the result of a burner pre-purge or other forms of time delay built into the burner’s safety circuits.
BOILER TARGET TEMPERATURE (BOIL TARGET)
The boiler target temperature is determined from the mode of operation and the type of demand applied. The control displays the temperature that it is currently trying to maintain at the operating sensor as BOIL TARGET in the View menu. The operating sensor for modes 1, 3, 4 and 6 is the boiler outlet sensor, and the operating sensor for modes 2, 5 and 7 is the boiler supply sensor. If the control does not presently have a requirement for heat, it displays “– – – ” in the LCD. There is no boiler target temperature generated in Mode 8.
BOILER MINIMUM (BOIL MIN)
The BOIL MIN setting is the lowest water 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 BOIL MIN setting, the boiler target temperature is adjusted to at least the BOIL MIN setting. During this condition, if the boiler is operating, the MIN segment turns on in the LCD while the boiler target temperature or boiler operating sensor temperature is viewed. If the installed boiler is designed for condensing or low temperature operation, set the BOIL MIN adjustment to OFF.
BOILER MAXIMUM (BOIL MAX)
The BOIL MAX setting is the highest water temperature that the control is allowed to use as a boiler target temperature. If the control does target BOIL MAX, and the temperature at the boiler outlet sensor is near the BOIL MAX temperature, the MAX segment turns on in the LCD while the boiler target, boiler inlet, boiler outlet or boiler supply temperature is viewed.
BOILER OUTLET MAXIMUM
The BOIL OUT MAX setting determines the highest water temperature allowed at the boiler outlet sensor. The boiler stages are immediately shut off once the water temperature exceeds the BOIL OUT MAX setting at the boiler outlet sensor location.
BOILER PUMP OPERATION ( )
The boiler pump contact operates when:
• A heat demand is present and parallel piping (Mode 1, 3, 4, 6) is used. Parallel piping requires the boiler pump to operate even while the boiler is off in order to provide heat to the system.
• While the boiler is on and primary / secondary piping (Mode 2, 5, 7) is used. Primary / secondary piping reduces standby losses by isolating the boiler from the system while the boiler is off.
• During external direct drive operation (Mode 8), the boiler pump contact closes whenever there is an internal heat demand.
• After the boiler shuts off the boiler pump remains on to purge heat from the boiler to the system.
BOILER PUMP PURGE ( DLY)
After the boiler is shut off, the control continues to operate the boiler pump for a period of time. The length of time that the boiler pump continues to run is based on the Pump DLY setting. Once the boiler turns off, the control keeps the boiler pump running for the time selected. This setting allows purging of any excess heat out of the boiler after the boiler is shut off. This also helps to prevent the water in the boiler from flashing into steam after the boiler is shut off.
When Pump DLY is set to OFF, there is no purging. When Pump DLY is set to ON, the pump runs continuously. When on is selected and the control is configured for outdoor reset, the pump continues to run even during Warm Weather Shut
PUMP EXERCISING
If the boiler pump has not operated at least once every 70 hours, the control turns on the output for 10 seconds. This minimizes the possibility of the pump seizing during a long period of inactivity.
ALERT
The control closes the alert contact whenever an error message is present.
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Partial Outdoor Reset
Decreasing Outdoor Air Temperature
Increasing Water Temperature
Boil MAXBoil MAX
Boil MINBoil MIN
WWSDWWSD
OUTDR DSGN
Boil DSGN
Boil START
OUTDR START
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A setpoint is a fixed water temperature target that the boiler is to maintain at the operation sensor once a demand is present. The boiler maintains the boiler target by operating the stages using proportional or PID logic together with the boiler differential.
Mode 1 or 2 and Heat Demand (Dem 1)
A heat demand is required whenever heat is required for the primary heating load. A heat demand is generated when a voltage between 24 and 120 V (ac) is applied across the CD (common demand) and the Ht D (heat demand). Once volt­age is applied, the control turns on the Dem 1 segment in the display and control operates the boiler stages to maintain the BOIL TARGET 1 at the boiler outlet sensor (Mode 1) or the boiler supply sensor (Mode 2).
Mode 1 or 2 and Setpoint Demand (Dem 2)
A setpoint demand is required whenever heat is required for the secondary heating load such as an indirect domestic hot water tank. A setpoint demand is generated when a voltage between 24 and 120 V (ac) is applied across the CD (common demand) and the Set D (setpoint demand) (pins 1 and 3). Once voltage is applied, the control turns on the Dem 2 segment in the display and control operates the boiler stages to maintain the BOIL TARGET 2 at the boiler outlet sensor (Mode 1) or the boiler supply sensor (Mode 2).
Modes 4 to 7 and Setpoint Demand (Dem 2)
A setpoint demand is required whenever heat is required for the secondary heating load such as an indirect domestic hot water tank. A setpoint demand is generated when a voltage between 24 and 120 V (ac) is applied across the CD (common demand) and the Set D (setpoint demand). Once voltage is applied, the control turns on the Dem 2 segment in the display and control operates the boiler stages to maintain the BOIL TARGET at the boiler outlet sensor (Mode 4, 6) or the boiler supply sensor (Mode 5, 7).
Section B: Setpoint Operation
Section C: Dedicated Domestic Hot Water (DHW) Operation
When mode 3 is selected, the BTC provides dedicated DHW operation.
A DHW tank temperature sensor is required to be connected on the Com and the Sup/D terminals (4 and 6). The DHW tank sensor must be installed in an immersion well to measure the tank temperature.
The TANK TARGET setting is used to set the desired DHW tank temperature. The TANK DIFF setting is the differential below the target.
An internal heat demand for DHW is generated when the measured DHW tank temperature falls below the TANK TARGET – TANK DIFF. The internal heat demand is removed once the measured DHW tank temperature exceeds the TANK TARGET.
Once an internal demand is generated, the Dem 1 segment turns on in the LCD. The control then closes the Pump contact, which starts the boiler pump and the control turns on the boiler pump segment in the display. The control then operates the boiler stages to maintain the programmed tank target temperature.
Note: A voltage does not need to be applied to the heat demand or the setpoint demand in this mode of operation.
Setpoint Operation
+ 1/2 Differential
Setpoint Target
-
1/2 Differential
Dedicated DHW Operation
Tank Target
Tank Target
-
Tank Differential
When either mode 4 or 5 is selected, the control uses outdoor reset to control the water temperature while a heat demand is present. Outdoor reset calculates the boiler target temperature based on the outdoor air temperature and reset ratio. As a result, the boiler target changes proportional to the outdoor temperature. The reset ratio is determined from the Boiler Start, Boiler Design, Outdoor Start and Outdoor Design settings.
HEAT DEMAND (Dem 1)
A heat demand is required whenever heat is required in the system. A heat demand is generated when a voltage between 24 and 120 V (ac) is applied across the CD (common demand) and the Ht D (heat demand) pins.
Once voltage is applied, the control turns on the Dem 1 segment in the display. If the control is not in warm weather shut down (WWSD), the control calculates a boiler target based on the reset ratio and outdoor air temperature. The pump and the boiler stages are operated to maintain the boiler target at the boiler outlet sensor (Mode 4), or the boiler supply sensor (Mode 5).
If the control is in WWSD, the WWSD segment is shown in the display and the boiler target in the View menu of the display remains “---“ (no target).
RESET RATIO
The control uses the four following settings to determine the reset ratio:
Boiler Start (BOIL START)
The BOIL START temperature is the theoretical boiler supply water temperature that the heating system requires when the outdoor air temperature equals the OUTDR START temperature setting. The BOIL START is typically set to the desired building temperature.
Outdoor Start (OUTDR START)
The OUTDR START temperature is the outdoor air temperature at which the control provides the BOIL START water temperature to the system. The OUTDR START is typically set to the desired building temperature.
Outdoor Design (OUTDR DSGN)
The OUTDR DSGN is the outdoor air temperature that is the typical coldest temperature of the year where the building is located. This temperature is used when completing heat loss calculations for the building.
Boiler Design (BOIL DSGN)
The BOIL DSGN temperature is the water temperature required to heat the boiler zones when the outdoor air is as cold as the OUTDR DSGN temperature.
Warm Weather Shut Down (WWSD)
When the outdoor air temperature rises above the WWSD setting, the control enters WWSD and turns on the WWSD segment in the display. Once the outdoor air temperature falls below the WWSD setting, the control exits WWSD. When the control is in Warm Weather Shut Down, the Dem 1 segment is displayed if there is a heat demand. However, the control does not operate the boiler to satisfy the heat demand. The control continues to respond to setpoint demands.
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Section E: External Temperature Target Input
When modes 6 or 7 are selected, the control allows for an external control to operate the boiler temperature through an external input signal provided by a Building Management System (BMS), Energy Management System (EMS), or tek­mar tN4 System Control. When in modes 6 or 7, the external heat demand (CD and Ht D) are disabled. The setpoint demand continues to operate as normal.
INTERNAL HEAT DEMAND
An internal heat demand is generated when an analog positive 0-10 V (dc) or 2-10 V (dc) signal is applied to the +V(in) input. The negative V (dc) signal is applied to the Com/- input.
0-10 V (dc) or 0-20 mA External Input Signal
The external input signal can be selected to be either 0-10 V (dc) or 2-10 V (dc) range. When the 0-10 V (dc) range is selected, an input voltage of 1 V (dc) corresponds to a boiler target temperature of 50°F (10°C). An input voltage of 10 V (dc) corresponds to a boiler target temperature of 210°F (99°C). As the voltage varies between 1 V (dc) and 10 V (dc), the boiler target temperature varies linearly between 50°F (10°C) and 210°F (99°C). If a voltage below 0.5 V (dc) is received, the boiler target temperature is displayed as “ – – – “ indicating that there is no longer an internal heat demand.
Section D: Outdoor Reset Operation
Reset Ratio
Decreasing Outdoor Air Temperature
Increasing Water Temperature
OUTDR DSGNOUTDR DSGN
Boil DSGNBoil DSGN
Boil STARTBoil START
OUTDR STARTOUTDR START
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A 0-20 mA signal can be converted to a 0-10 V (dc) signal by installing a 500 Ohm resistor on the external input signal device’s terminals.
2-10 V (dc) or 4-20 mA External Input Signal
The external input signal can be selected to be either 0-10 V (dc) or 2-10 V (dc) range. When the 2-10 V (dc) range is selected, an input voltage of 2 V (dc) corresponds to a boiler target temperature of 50°F (10°C). An input voltage of 10 V (dc) corresponds to a boiler target temperature of 210°F (99°C). As the voltage varies between 2 V (dc) and 10 V (dc), the boiler target temperature varies linearly between 50°F (10°C) and 210°F (99°C). If a voltage below
1.5 V (dc) is received the boiler target temperature is displayed as “ – – – “ indicating that there is no longer an internal heat demand.
A 4-20 mA signal can be converted to a 2-10 V (dc) signal by installing a 500 ohm resistor on the external input signal device’s terminals.
OFFSET
The Offset setting allows the boiler target temperature to be fine tuned to the external input signal. The control reads the external input signal and converts this to a boiler target temperature. The Offset setting is then added to the boiler target temperature.
Section F: External Direct Drive Operation
When mode 8 is selected, the control allows for an external control to operate the boiler through an analog direct drive input signal provided by a boiler sequencing control such as a tekmar Boiler Control 275. When in mode 8, the external heat demand (CD and Ht D) and the setpoint demand (CD and Set D) are disabled.
DIRECT DRIVE INPUT SIGNAL
An external boiler sequencer provides a positive 0-10 V (dc) input signal to the control +V(in) input. The negative V (dc) signal is applied to the Com/- input.
The boiler burner remains off while the direct drive input signal range is between 0 to 0.5 V (dc). The Stage 1 contact remains on as long as the direct drive input signal is over 0.5 V (dc). The Stage 2 contact is activated once the direct drive input signal reaches or exceeds 3.0 V (dc). Stage 3 contact is activated once the direct drive input signal reaches or exceeds 5.5 V (dc). Stage 4 contact is activated once the direct drive input signal reaches or exceeds 8.0 V (dc).
PUMP OPERATION
The pump is turned on as soon as the direct drive input signal reaches 0.5 V (dc). Once the direct drive input signal falls below 0.5 V (dc), the pump continues to operate until the Pump DLY purge expires, then the pump shuts off.
BOILER OUTLET MAXIMUM TEMPERATURE
The external boiler sequencer is able to operate the boiler temperature. However, the BOIL OUT MAX setting limits the highest temperature at the boiler outlet sensor. Should the boiler outlet temperature exceed the BOIL OUT MAX setting, the Stage contacts are opened to shut off the burner. The burners remains off for the minimum off time and the boiler outlet temperature falls 2°F (1°C) below the BOIL OUT MAX setting.
0-10 V (dc) 0-20 mA* Boiler Target
0 0 --- (OFF)
1 2 50°F (10°C)
2 4 68°F (20°C)
3 6 86°F (30°C)
4 8 103°F (39°C)
5 10 121°F (49°C)
6 12 139°F (59°C)
7 14 157°F (69°C)
8 16 174°F (79°C)
9 18 192°F (89°C)
10 20 210°F (99°C)
*requires a 500 ? resistor
2-10 V (dc) 4-20 mA* Boiler Target
0 0 --- (OFF)
1 2 --- (OFF)
2 4 50°F (10°C)
3 6 70°F (21°C)
4 8 90°F (32°C)
5 10 110°F (43°C)
6 12 130°F (54°C)
7 14 150°F (66°C)
8 16 170°F (77°C)
9 18 190°F (88°C)
10 20 210°F (99°C)
*requires a 500 ? resistor
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)
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