tekmar 263 User Manual

0 (0)

- Data Brochure

Boiler Control 263

D 263

03/09

The tekmar Boiler Control 263 can control the supply water temperature from a single modulating boiler or up to 2 on / off stages based on outdoor temperature, domestic hot water requirements, or setpoint requirements. A large easy to read display provides current system temperatures and operating status. The control has an internal setback timer, which can have 2 events per day on a 24 hour, 5-1-1 day or 7 day schedule.

Additional functions include:

• Outdoor Reset

• Installer and Advanced access levels

• Primary pump output

• Pump exercising

• Pump purging

• Boiler demand for space heating loads

• DHW demand for domestic hot water loads

Note:

Boiler, DHW, or setpoint demand must be powered with 20 to 260 V (ac) before the boiler is able to fire.

Menu Item

Boiler Control 263

Two Stage / One Modulating Boiler, DHW & Setpoint

1 2 3

Boiler

Demand

DHW Dem

Com Dem

6 7NL8

Setp

Prim

Dem

Power

• Setpoint demand for setpoint loads

• Optional indoor sensor for room air temperature control

• Test sequence to ensure proper component operation

• Internal setback timer for energy savings

• Setback input for energy savings

• CSA C US certified

Soft Stop

Setback

Boiler Demand

DHW Demand

Setpoint Demand

Modulation

Priority Override

9 10 11 12113114 15+16-17 18 19 20 21 22 23

DHW

Pmp/Vlv

Relay

Relay Mod 1 mA

2/P2

Advanced

Installer

None

Modes

1 Two On/Oﬀ Stages 2 One Modulating Boiler and Pump

Made in Canada by tekmar Control Systems Ltd.

Power 115 V ±10% 50/60 Hz 600 VA Relays 230 V (ac) 5 A 1/3 hp, pilot duty 240 VA Demands 20 to 260 V (ac) 2 VA

Signal wiring must be rated at least 300 V.

Rotate

DHW Sensor

Oﬀ

Exercise

Oﬀ

Test

Do not apply power

Com Com Boil Out

DHW Indr

UnO

oﬀ not testing

testing

red

testing paused

red

For maximum heat press & hold Test for 3 seconds.

Meets Class B: Canadian ICES FCC Part 15

Date Code

H2038B

Input

Boiler

Demand

Input

DHW

Demand

Input

Setpoint

Demand

OR OR

Input

Outdoor Sensor

Included

Input

Universal Sensor

Included

Input

Indoor Sensor

Optional

Input

Output

Primary

Pump

Input

115 V (ac)

Power Supply

Output

DHW Pump or

DHW Valve

Output

Boiler

Output

Boiler

Output

Pump

Output

Boiler

Output

tekmar

Timer

Universal Sensor

Optional

How To Use The Data Brochure

This brochure is organized into four main sections. They are: 1) Sequence of Operation, 2) Installation, 3) Control Settings, and 4) Testing and Troubleshooting. The Sequence of Operation section has six sub-sections. We recommend reading Section A: General of the Sequence of Operation, as this contains important information on the overall operation of the control. Then read the sub sections that apply to your installation.

The Control Settings section (starting at DIP Switch Settings) of this brochure describes the various items that are adjusted and displayed by the control. The control functions of each adjustable item are described in the Sequence of Operation.

Table of Contents

User Interface ..................................................Pg 2

Display ............................................................. Pg 3

Sequence of Operation ..................................Pg 4

Section A: General Operation .............. Pg 4

Section B: Boiler Operation.................. Pg 6

Section C: Pump Operation .................. Pg 11

Section D: Boiler Reset Operation ......Pg 12

Section E: DHW Operation ...................Pg 14

Section F: Setpoint Operation ..............Pg 17

Installa tion ....................................................... Pg 18

DIP Switch Settings ........................................Pg 25

Control Settings ..............................................Pg 26

View Menu ..............................................Pg 26

Adjust Menu ...........................................Pg 27

Time Menu .............................................. Pg 30

Schedule Menu ......................................Pg 31

Testing the Control ......................................... Pg 32

Error Messages ...............................................Pg 33

Technical Data .................................................Pg 36

Limited Warranty ............................................Pg 36

User Interface

The control uses a Liquid Crystal Display (LCD) as the method of supplying information. You use the LCD in order to setup and monitor the operation of your system. The control has four push buttons (Menu, Item, ▲, ▼) for selecting and adjusting settings. As you program your control, record your settings in the ADJUST menu table, which is found in the second half of this brochure.

All of the items displayed by the control are organized into four menus (View, Adjust, Time, Schedule). These menus are listed on the top left hand side of the display (Menu

Field). To select a menu, use the Menu button. By pressing and releasing the Menu button, the display sequences between the four menus. Once a menu is selected, there will be a group of items that can be viewed within the menu.

Menu Item

Item

The abbreviated name of the selected item will be displayed in the item field of the display. To view the next available item, press and release the Item button. Once you have reached the last available item in a menu, pressing and releasing the Item button will return the display to the first item in the selected menu.

The items can be quickly scrolled through by holding the Item button and then pressing the ▼ button. To rapidly scroll through the items in the reverse order, hold the Item button and press the ▲ button.

Adjust

To make an adjustment to a setting in the control, begin by selecting the ADJUST, TIME or SCHEDULE menu using the Menu button. Then select the desired item using the Item button. Finally, use the ▲, and / or ▼ button to make the adjustment.

Additional information can be gained by observing the Status field of the LCD. The status field will indicate which of the control’s outputs are currently active. Most symbols in the status field are only visible when the VIEW menu is selected. .

Menu Item

Display

Menu Field

Displays the current menu

Item Field

Displays an abbreviated name of the selected item

Status Field

Displays the current status of the control's inputs, outputs and operation

Number Field

Displays the current value of the selected item

Boiler Demand DHW Demand Setpoint Demand Modulation Priority Override

Buttons

Selects Menus, Items and adjust settings

Symbol Description

Burner

Displays when Relay 1 and / or Relay 2 is turned on.

Pump

Displays when the primary or boiler pump is operating.

DHW

Displays when the DHW pump is on.

Boost

Displays when the control is in boost after setback.

Occupied Schedule

Displays when the control is in occupied mode.

UnOccupied Schedule

Displays when the control is in unoccupied mode.

Warning

Displays when an error exists or when a limit has been reached.

Lock / Unlock

Displays when the Advanced / Installer DIP switch is set to Installer.

°F, °C, min, hr, %

Units of measurement.

Pointer

Displays the control operation as indicated by the text.

Day of Week

Displays the day of the week and indicates morning or afternoon.

Modulating Output Scale

Displays the total modulation output level of the boiler.

Definitions

The following defined terms and symbols are used throughout this manual to bring attention to the presence of hazards of various risk levels, or to important information concerning the life of the product.

- Warning Symbol: Indicates presence of hazards which can cause severe personal injury, death or substantial property damage if ignored.

INSTALLATION

CATEGORY II

- Double insulated

- Local level, appliances

Sequence of Operation

Section A

General

Operation

Page 4 - 5

Section F

Setpoint

Operation

Page 17 - 18

Section B

Boiler

Operation

Page 6 - 10

Section C

Pump

Operation

Page 11

Section D

Boiler Reset

Operation

Page 12 - 14

Section E

DHW

Operation

Page 15 - 17

Section A: General Operation

POWERING UP THE CONTROL

When the control is powered up, all segments in the LCD are turned on for 2 seconds. Next, the control displays the control type number in the LCD for 2 seconds. Next, the software version is displayed for 2 seconds. Finally, the control enters into the normal operating mode.

OPERATING MODES

The control operates in two different operating modes:

Mode 1 – Two ON / OFF Stages

Mode 1 operates up to two on / off boilers or one boiler with two stages.

Mode 2 – One Modulating Boiler & Pump

Mode 2 operates one modulating boiler and the boiler pump.

Primary

Pump

Primary

Pump

DHW

Pump

Sensor

DHW

Pump

Boiler

Sensor

Boiler

Boiler Pump

TYPES OF DEMANDS

The control stages or modulates the boiler(s) to control supply water temperature to a hydronic system. The supply water temperature is based on outdoor reset, a fixed temperature for DHW, or a fixed temperature for setpoint.

Boiler Reset

When a boiler demand signal from the heating system is present, the control operates the boiler(s) to maintain the supply temperature based on the outdoor air temperature and the Characterized Heating Curve settings. Refer to section D.

DHW

When a DHW demand is present, the control operates the boiler(s) to maintain the supply water temperature at least as hot as the DHW exchange setting or high enough to satisfy tank temperature. Refer to section E.

Setpoint

When a setpoint demand signal is present, the control operates the boiler(s) to maintain the supply water temperature at least as hot as the Setpoint setting. Refer to section F.

SETBACK (Occ and UnOcc)

To provide greater energy savings, the control has a setback feature. With setback, the supply water temperature in the system is reduced when the building is unoccupied. By

Com

UnO

reducing the supply water temperature, the air temperature in the space may be reduced even when thermostat(s) are not turned down.

The control has an internal setback timer with two events per day on either a 24 hour, a 5-1-1 day or a 7 day schedule.

The control also has an external setback input. Any time the UnO Sw (18) and t he Com (17)

Timer Switch

are shorted together, the control operates in the unoccupied mode.

The external setback overrides the internal setback timer schedule to place the control into the unoccupied period.

When in the unoccupied mode, the UNOCC segment is displayed in the LCD. The control adjusts the supply water temperature based on the UNOCC settings made in the control.

EXERCISING

The control has a built-in exercising feature that is selected through the Exercise / Off DIP switch. To enable the exercising feature set the Exercise / Off DIP switch to Exercise. If exercising is enabled, the control ensures that each pump is operated at least once every 3 days. If a pump has not been operated at least once every 3 days, the control turns on the output for 10 seconds. This minimizes the possibility of the pump seizing during a long period of inactivity. While the control is exercising, the Test LED flashes quickly.

Note: The exercising function does not work if power to the control or pumps is disconnected.

RUNNING TIMES

The control displays the accumulated running time of each boiler in the VIEW menu.

Resetting the Running Times

To reset the running time for each boiler, select the appropriate running time in the VIEW menu. Next press the ▲ and ▼ buttons simultaneously until CLR is displayed.

FACTORY D EFAULTS

The control comes preset with several factory defaults. These are based on the terminal unit selection. To fine-tune building requirements, these defaults may be changed.

To reload the factory default, power down the control and wait for 10 seconds. Power up the control while simultaneously holding the Menu and ▼ buttons. An E01 error occurs forcing the installer to go through the ADJUST menu to ensure the settings are correct.

Section B: Boiler Operation

Section B1

Boiler

Operation

Section B2

Mode 1

Two St age

Operation

Section B3

Mode 2

Modulating

Boiler Operation

Section B1: Boiler Operation

BOILER TARGET TEMPERATURE

The boiler target temperature is determined by the type of demand received by the control. A boiler demand calculates a boiler target based on the characterized heating curve settings and the outdoor air temperature. A DHW demand and a Setpoint demand have temperature settings to which the boilers are operated to meet.

The control displays the temperature that it is currently trying to maintain as the boiler supply temperature. 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.

BOILER MINIMUM

The boiler minimum is the lowest temperature that the control is allowed to use as a boiler target temperature. During mild conditions, if the control calculates a boiler target temperature that is below the Boiler Minimum setting, the boiler target temperature is adjusted to at least the Boiler Minimum setting. During this condition, if the boiler(s) is operating, the minimum segment is turned on in the display when viewing either the boiler supply temperature or the boiler target temperature. Set the Boiler Minimum setting to the boiler manufacturer’s recommended temperature.

MIN Segment On

BOILER MAXIMUM

The boiler maximum is the highest temperature that the control is allowed to use as a boiler target temperature. If the control does target the Boiler Maximum setting, and the boiler temperature is near the boiler

MAX Segment

maximum temperature, the maximum segment will be displayed in the LCD while either the boiler target temperature or the boiler temperature is being viewed. At no time does the control operate the boiler(s) above 248°F (120°C).

Boiler Contact Closes

Boiler Fires

FIRE DELAY

The Fire Delay is the time delay that occurs between the time that the control closes a stage contact to fire a stage and the burner fires for that stage.

Fire

Delay

Time

Section B2: Mode 1 - Two On / Off Stages Operation

STAGING

When operating in mode 1, the control operates up to two on / off stages in order to provide the required supply temperature. After a stage is turned on in the firing sequence, the control waits for a minimum time delay. The minimum time delay is adjustable using the Stage Delay setting. After the Stage Delay has expired, the control examines the control error to determine when the next stage is to fire. The control error is determined using Proportional, Integral and Derivative (PID) logic.

Proportional compares the actual supply temperature to the boiler target temperature. The colder the supply water temperature,

the sooner the next stage is turned on.

Integral compares the actual supply temperature to the boiler target temperature over a period of time.

Derivative compares how fast or slow the supply water temperature is changing. If the supply temperature is increasing

slowly, the next stage is turned on sooner. If the supply temperature is increasing quickly, the next stage is turned on later, if at all.

ROTATION

The control’s Equal Run Time Rotation function is fixed at 48 hours. The firing order of the boilers changes whenever one boiler accumulates 48 hours more running time than the other boiler. After each rotation, the boiler with the least running hours is the first to fire and the boiler with the most running hours is the last to fire. This function ensures that both boilers receive equal amounts of use. When the Rotate / Off DIP switch is set to the Off position, the firing sequence always begins with boiler one and then boiler two.

Note: When using a single two-stage boiler, ensure that the Rotate / Off DIP switch is set to Off.

720 hours 672 hours

Resetting the Rotation Sequence

672 hours 720 hours

To reset the rotation sequence, set the Rotate / Off DIP switch to the Off setting for 5 seconds and then return the DIP switch to the Rotate setting.

STAGE DELAY

The stage delay is the minimum time delay between the firing of stages. After this delay has expired the control can fire the next stage if it is required. This setting can be adjusted manually or set to an automatic setting. When the automatic setting is used, the control determines the

Boiler 1 Contact Closes

Fire

Delay

Boiler 1 Fires

Stage Delay

Time

Boiler 2 Contact Closes

Fire

Delay

Boiler 2 Fires

best stage delay based on the operation of the system.

BOILER MASS

The Boiler Mass setting allows the installer to adjust the control to the thermal mass of the type of heat sources used in the application. If the heating system is causing the boiler(s) to be staged on and off in rapid succession, a higher Boiler Mass setting will result in a decrease in the amo unt of cycling. Conversely, if t he system is s low to resp ond to heat requiremen ts, then dec reasing the Boiler Mass setting will increase the response rate by staging the boilers at a faster rate.

Lo (1)

The Lo setting is selected if the boiler(s) that is used has a low thermal mass. This means that the boiler(s) has a very small water content and has very little metal in the heat exchanger. A boiler that has a low thermal mass comes up to temperature quite rapidly when fired. This is typical of many copper fin-tube boilers. The Lo Mass setting provides a fast staging rate of additional on / off boiler stages.

Med (2)

The Med setting is selected if the boiler(s) that is used has a medium thermal mass. This means that the boiler(s) either has a large water content and a low metal content or a small water content and a high metal content. This is typical of many modern residential cast iron boilers or steel tube boilers. The Med Mass setting provides a moderate staging rate of additional on / off boiler stages.

Hi (3)

The Hi setting is selected if the boiler(s) that is used has a high thermal mass. This means that the boiler(s) has both a large water content and a large metal content. A boiler that has a high thermal mass is relatively slow in coming up to temperature. This is typical of many commercial cast iron and steel tube boilers. The Hi Mass setting provides a slow staging rate of additional on / off boiler stages.

DIFFERENTIAL

An on / off heat source must be operated with a differential in order to prevent short cycling. With the control, either a fixed or an auto differential may be selected. The boiler differential is divided around the boiler target temperature. The stage contact closes when the supply water temperature is ½ of the differential setting below the boiler target temperature. Additional staging occurs if the first stage is unable to raise the supply water temperature up to the boiler target temperature at a reasonable rate. As the supply temperature reaches ½ of the differential above the boiler target temperature, stages are staged off.

Desired temperature 160°F (71°C)

Boiler Oﬀ

Boiler On

165°F (74°C)

155°F (68°C)

Fixed Differential

If the user desires to have a fixed differential, this is set using the Boiler Differential setting in the ADJUST menu.

Time

Diﬀerential

10°F (6°C)

Auto Differential

Oﬀ

If the Auto Differential is selected, the control automatically determines the best differential as the load changes. This reduces potential short cycling during light load conditions.

Diﬀerential

Increasing Load

Time

Section B3: Mode 2 - One Modulating Boiler and Pump Operation

MODULATION

When operating in Mode 2, the control provides a modulating output signal to operate a single modulating boiler. The control first closes the boiler contact on to ignite the ignition sequence. The boiler is then modulated from the minimum modulation using Proportional, Integral and Derivative (PID) logic in order to satisfy the boiler target temperature.

MOTOR SPEED

The Motor Speed 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 open 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.

MODULATION RANGE (4 to 20 mA or 0 to 20 mA)

The modulation output (Mod 1) can be adjusted from a 4 to 20 mA output range or to a 0 to 20 mA output range using the Boil Modulation setting. The resulting modulation output signal can be converted to a 0 to 5 V (dc), 1 to 5 V (dc), 0 to 10 V (dc), and 2 to 10 V (dc) output using external resistors. The modulation output signal can be converted to a 0 to 135 Ω (W R B) output using a 0 to 135 Ω Converter 005. Refer to the Modulation Output section in Step 4 of the Installation section.

MINIMUM MODULATION

The minimum modulation defines the minimum output signal from the control to the boiler burner. It is based on a percentage of the control’s output signal range.

The Minimum Modulation setting for boilers with power burners is typically set to 0%.

For boilers with electronic operators, the boiler’s input signal range may not match the output signal range of the 263 control. The Minimum Modulation setting limits the control output range in order to match the boiler’s input range.

To calculate the Minimum Modulation, use the following formulae:

For 4 to 20 mA:

Minimum Modulation =

4 mA – Boiler’s Minimum Input Signal

4 - 20 mA

For 0 to 10 V (dc):

Minimum Modulation =

0 V (dc) – Boiler’s Minimum Input Signal

0 – 10 V (dc)

For 2 to 10 V (dc):

Minimum Modulation =

2 V (dc) – Boiler’s Minimum Input Signal

2 – 10 V (dc)

x 100%

MINIMUM MODULATION

Control's

Output

Signal

Range

Minimum Modulation

100%10 V (dc) 10 V (dc)

Boiler's Input Signal Range

18%

0%0 V (dc)

1.8 V (dc)

Boiler's Minimum

Input Signal

Example 1:

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. This means the boiler’s input signal range is 1.8 to 10 V (dc). The 263 control has an output signal range of 0 to 20 mA which can be externally converted to 0 to 10 V (dc) using a 500 Ω resistor (Refer to Modulation Output section in Step 4 of the Installation section).

To make the two signal ranges the same, the Minimum Modulation required is:

Minimum Modulation

0 V – 1.8 V

0 V – 10 V

x 100% = 18%

Example 2:

If the boiler’s input signal range is 6 to 20 mA the required Minimum Modulation is:

Minimum Modulation =

4 mA – 6 mA

4 mA – 20 mA

x 100% = 13%

MAXIMUM MODULATION

The maximum modulation defines the maximum output signal from the control to the boiler burner. It is based on a percentage of the control’s output signal range.

The Maximum Modulation setting for boilers with power burners is typically set to 100%.

For boilers with electronic operators, the boiler’s input signal range may not match the output signal range of the 263 control. The Maximum Modulation setting limits the control output range in order to match the boiler’s input range.

To calculate the Maximum Modulation, use the following formulae:

For 4 to 20 mA: Maximum Modulation =

4 mA – Boiler’s Maximum Input Signal

4 – 20 mA

x 100%

For 0 to 10 V (dc): Maximum Modulation =

For 2 to 10 V (dc):

Maximum Modulation =

0 V (dc) – Boiler’s Maximum Input Signal

0 – 10 V (dc)

2 V (dc) – Boiler’s Maximum Input Signal

2 – 10 V (dc)

x 100%

Maximum

Modulation

Example 1:

A boiler’s input signal range is 2 to 9 V (dc). The 263 control has an output signal range of 2 to 10 V (dc).

To make the two signal ranges the same, the Maximum Modulation required is:

Maximum Modulation =

2 V – 9 V

2 V – 10 V

x 100% = 88%

MAXIMUM MODULATION

Control's

Output

Signal

Range

100%10 V (dc)

88%

9 V (dc)

Boiler's Input Signal Range

0%2 V (dc)

2 V (dc)

Boiler's

Maximum

Input Signal

Example 2:

If the boiler’s input signal range is 6 to 19 mA the required Maximum Modulation is:

Maximum Modulation =

4 mA – 19 mA 4 mA – 20 mA

x 100% = 94%

BOILER MASS

The Boiler Mass setting allows the installer to adjust the control to the thermal mass of the type of heat sources used in the application. The modulation of the boiler can become unstable if the incorrect Boiler Mass setting is chosen. A key sign of the boiler modulation being unstable is the flame will continue to increase and then decrease in short periods of time. By choosing a lower Boiler Mass setting, the boiler response will become more stable.

Lo (1)

The Lo setting is selected if the boiler that is used has a low thermal mass. This means that the boiler has a very small water content and has very little metal in the heat exchanger. A boiler that has a low thermal mass comes up to temperature quite rapidly when fired. This is typical of many copper fin-tube boilers. The Lo Mass setting provides a fast response to the heating system.

Med (2)

The Med setting is selected if the boiler that is used has a medium thermal mass. This means that the boiler either has a large water content and a low metal content or a low water content and a high metal content. This is typical of many modern residential cast iron boilers or steel tube boilers. The Med Mass setting provides a moderate response to the heating system.

Hi (3)

The Hi setting is selected if the boiler that is used has a high thermal mass. This means that the boiler has both a large water content and a large metal content. A boiler that has a high thermal mass is relatively slow in coming up to temperature. This is typical of many commercial cast iron and steel tube boilers. The Hi Mass setting provides a slow response to the heating system.

DIFFERENTIAL

A modulating boiler must be operated with a differential while operating in low fire. The boiler differential is divided around the boiler target temperature. The boiler burner ignites at low fire when the supply water temperature is ½ of the Boiler Differential setting below the boiler target temperature. The boiler is shut off in low fire as the supply temperature reaches at least ½ of the differential above the boiler target temperature. With the control, either a fixed or an auto differential may be selected.

When the boiler is modulating above low fire, the differential does not apply. Instead, the modulation output signal is determined using Proportional, Integral and Derivative (PID) logic in order to satisfy the boiler target temperature.

Desired temperature

Fixed Differential

If the user desires to have a fixed differential, this is set using the Boiler Differential setting in the ADJUST menu.

160°F (71°C)

Boiler Oﬀ

Boiler On

165°F (74°C)

Time

155°F (68°C)

Diﬀerential

10°F (6°C)

Auto Differential

Oﬀ

If the Auto Differential is selected, the control automatically determines the best differential as the load changes. This reduces potential short cycling during light load conditions.

Diﬀerential

Increasing Load

Time

SOFT STOP

It is possible to thermally shock a boiler when it is shut off at high fire. The Soft Stop feature forces the boiler to modulate down to a minimum before turning off. This is designed to prevent large volumes of cold air being introduced into the combustion chamber of the boiler when it is shut off. This can occur in applications where the burner includes a fan.

Once all d emands are removed, the con trol allows for the firing r ate to be modulated down to the Minimum M odulation setting prior to t urning off the burner. This feature is enabled by setting the Soft Stop / Off DIP switch to the Soft Stop position. If the Soft Stop / Off DIP switch is in the Off position, the control turns off the boiler at the current firing rate once all demands are removed.

Section C: Pump Operation

Section C1

Pump

Operation

Section C1: Pump Operation

PRIMARY PUMP OPERATION

The primary pump operates under the following conditions:

• A boiler demand is present and the control is not in Warm Weather Shut Down (WWSD).

• A DHW demand is present and DHW MODE is set to 3 or 4.

• A setpoint demand is present and Setpoint MODE is set to 3.

Primary Pump Purge

After a demand is removed, the control continues to operate the primary pump for a period of time. The maximum length of time that the primary pump continues to run is adjustable using the Primary Pump Purge setting. The primary pump continues to run until either the purging time has elapsed or the boiler supply temperature drops more than a differential below the Boiler Minimum setting.

BOILER PUMP OPERATION (MODE 2 ONLY)

When the control is operating in Mode 2 - One Modulating Boiler and Pump, the control can operate the boiler pump on the boiler in addition to the primary pump. The boiler pump turns on prior to the boiler firing (pre-purge) and continues to run after the boiler is turned off (post-purge). The boiler pump pre-purge time is determined by the Boiler Mass setting. As the Boiler Mass setting is increased, the boiler pump pre-purge time of the boiler also increases. However, if the control is operating based on a setpoint demand, the boiler pump turns on prior to the boiler.

Boiler Pump Purge (Mode 2 Only)

The amount of time that the boiler pump continues to run after the boiler turns off is adjustable using the Boiler Pump Purge setting.

+ 25 hidden pages