356214-XIM-A-0108

When the thermostat calls for the first stage of heating, the low-voltage control circuit from "R" to "W1" and "G" is completed, thru the UCB. The heat relay "RW1" is energized. The "RW1-2" contacts close energizing the draft motor control. The draft motor control contacts close and start the draft motor. As the speed of the draft motor reaches approximately 2500 RPM, the cen- trifugal switch contact, located on the end of the draft motor shaft, closes to power the first stage ignition module "IC1", thru the "RW1-1 contacts.

Ignition module "IC1" will immediately start the first stage igniter sparking and will open the redundant valve located inside the first stage main gas valve "GV1" to allow a flow of gas to only the first stage carry- over tube. Only after the pilot flame has been ignited and the presence of pilot flame detected at the "IC1" by a signal sent back through the flame sensor is sparking terminated and the first stage main gas valve opened.

Gas flows into each of the main burners and is ignited from the carryover tube flame.

After completing the specified fan on delay for heating, the UCB will energize the blower motor.

If "IC1" fails to detect a pilot flame, it will continue to try for a maximum of 85 seconds to ignite the pilot tube. If the pilot flame is not detected, then "IC1" will lock out first stage furnace operation for five minutes or until 24V power is removed from the module either at the unit or by resetting the room thermostat.

When the thermostat calls for the second stage of heating, the low-voltage control circuit from "R" to "W2" is completed, thru the UCB. Heat relay "RW2" is ener- gized. The "RW2-1" contact is closed energizing the second stage ignition module "IC2". "IC2" will immedi- ately start the second stage igniter sparking and will open the redundant valve located inside the second stage main gas valve "GV2" to allow a flow of gas to the second stage carryover tube. Only after the pilot flame has been ignited and the presence of pilot flame detected at "IC2" by a signal sent back through the flame sensor is sparking terminated and the main gas valve opened.

Gas flows into each of the second stage main burners and is ignited from the carryover tube flame.

If "IC2" fails to detect a pilot flame, it will continue to try for a maximum of 85 seconds to ignite the pilot tube. If the pilot flame is not detected, then "IC2" will lock out first stage furnace operation for five minutes or until

24V power is removed from the module either at the unit or by resetting the room thermostat.

NOTE: That the second stage furnace can operate even if first stage has locked out.

When the thermostat satisfies de-energizing the "RW2"and "RW1", thus opening all gas valves. The blower motor will continue to run after the furnace is shut down until the specified fan off delay for heating has been satisfied. The UCB will de-energize the blower motor.

REDUNDANT

 

MAIN VALVE

VALVE

 

 

GAS MAIN

 

GAS

 

TO MAIN

VALVE

TO PILOT BURNER

BURNER

 

 

FIGURE 19 - GAS VALVE PIPING

When the thermostat calls for the first stage of heating, the low-voltage control circuit from "R" to "W1" is com- pleted. A call for heat passes through the UCB to the ignition control board (ICB). The UCB monitors the "W1" call and acts upon any call for heat. Once voltage has been sensed at “W1”, the UCB will initiate the fan on delay for heating, energizing the indoor blower after the specified delay has elapsed.

When the thermostat has been satisfied, heating calls are ceased. The GV is immediately de-energized. The blower is de-energized after the fan off delay for heat- ing has elapsed. The draft motor performs a 25-second post purge.

GAS HEATING OPERATION ERRORS

TEMPERATURE LIMIT

If the UCB senses zero volts from the high temperature limit, the indoor blower motor is immediately energized. When the UCB again senses 24 volts from the temper- ature limit, the draft motor will perform a 25-second post-purge and the indoor blower will be de-energized following the elapse of the fan off delay for heating.

This limit is monitored regardless of unit operation sta- tus, i.e. the limit is monitored at all times.

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Johnson Controls Unitary Products

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Sunlife Enterprises DM240, DM300, DM180 installation manual GAS Valve Piping, GAS Heating Operation Errors
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DM300, DM240, DM180 specifications

Sunlife Enterprises has made significant strides in the competitive market of digital management tools with their innovative lineup of products: the DM240, DM300, and DM180. Each of these devices has been engineered to cater to specific operational needs while sharing a common foundation of advanced technology, versatility, and user-centric design.

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In summary, Sunlife Enterprises’ DM240, DM300, and DM180 models stand out for their unique features designed to meet the evolving needs of businesses. With a focus on user experience, performance, and security, these devices are poised to help organizations enhance productivity and drive innovation in the digital management landscape.
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