WARNING
!
Commissioning Procedures:
Ensure that ball valve to the heater is turned “OFF”.
Purge air from the gas supply line and test for gas soundness in accordance with relevant Standards.
Check that all electrical connections are made to the heater and that the unit has a sound earth
connection.
Remove operating pressure test point screw and connect the pressure gauge.
Switch on power to the heater. After a purge period, the gas valve is energized and will atempt to
ignite for 5-10 seconds. (If ignition fails, the heater will lock out). To reset the heater, briefly interrupt
power to the heater.
With the heater running, test operating pressure. Refer to the Technical Specifications chart on page
3 for details on your particular gas type.
Lighting Procedures:
Verify that service lid is secured.
Open (turn on) gas supply to the heater.
Close (turn on) electrical circuit (typically thermostat).
If the heater fails to light, turn off gas, open electrical circuit (set thermostat to lowest setting or to off).
Wait five (5) minutes before repeating above steps.
Shutdown Procedures:
Open (turn off) electrical circuit.
Close (turn off) gas supply to the heater.
Wait five (5) minutes before relighting heater.
This heater is not equipped with a pilot ignition system.
Do not attempt to light the system manually.
4.0
Operation
- GTD Series Installation, Operation, Maintenance and Parts Manual
4.0 Operation
Starting Circuit
Upon a call for heat, the circuit board verifies that the pressure switch is in the proper position (open). The
circuit board energizes the blower. Once operational static pressure is achieved, the differential switch will
close initiating the ignition sequence. The system is purged for 10 seconds and the circuit board sends a
spark through the electrode. The gas valve is opened and an attempt at ignition is made for 10 seconds. If
ignition fails, the heater will go into lockout until the electrical supply is interrupted for more than two seconds.
Running Circuit
After ignition, the flame rod monitors the flame. As long as flame is present, the valve is held open. If the
flame is lost, the circuit board acts to close the valve within one second and a new trial sequence identical
to that at startup is initiated. If proof of flame is not established within 10 seconds, the unit will lock out. If
lockout occurs, the control can be reset by briefly interrupting the power source.
Sequence of Operation
35
2
3
4
1
5
6
2
3
4
1
2
3
1
