Overview:
What is the Sequence of Operation for Voyager II Modulating Gas Heat?
Process:
Thermostat Heating Operation with Modulating Heat
Units controlling modulating heat with thermostat inputs will use the Discharge Air Setpoint (DASP) from the RTOM (50-150 degrees F) to control the temperature of the units discharge air within +/- 2.0 degrees F (measured by the discharge air sensor). The discharge air will be used to satisfy the thermostat call from the space.
Call for 1st stage heat (W1) (0 80% Modulation)
Heat output signal is at 100% for 1 minute prior to start of modulation.
Heat output will modulate through Supply Air heat algorithm control for a minimum of 15 minutes.
If the modulating heat output reaches 80% fire and remains there for 15 consecutive minutes without a call for 2nd stage heat, the modulating heat output will go to 100% until all heat calls are cleared.
If the DASP is satisfied, the output signal reduces to minimum fire (2.0Vdc) and the gas heat will remain energized at min fire until the heat call is cleared to prevent unnecessary cycling.
Heat output goes to 100% for 5 seconds for a post purge prior to the heat being turned off.
The 15 minute inter-stage timer is then reset.
Call for 2nd stage heat (W1 + W2, W2)
Go to 100% fire until W2 call is released.
If heat call goes back to first stage then see section above.
If tall heat calls go away heat output goes to 100% for 5 seconds for a post purge prior to the heat being turned off.
The 15 minute inter-stage timer is then reset.
*Note 1: If zone temperature falls to 3 degrees F below the heat SP then output control will be set to 100% (Recovery) until the zone temperature rises to 2 degrees F above the heat SP.
*Note 2: Modulating heat output is 0VDC when there is no call for heat.
Zone Sensor Heating Operation with Modulating Heat
On a modulating heat unit, when a call for heat is received, the burner will light at full fire (100%). After burner is lit, the unit controls will calculate a Discharge Air Setpoint and modulate the input rate down to match the load.
Units controlling modulating heat with zone sensor inputs will use the Active Zone Heating Setpoint and the Active Zone Temperature to control the temperature of the units discharge air through the use of an algorithm programmed into the RTRM.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.