Roberts Gorden CGTH-50 OPERATION 8.1 Operating Instructions, To Turn Off Gas To Heater, Testing

CGTH INSTALLATION, OPERATION AND SERVICE MANUAL

SECTION 8: OPERATION 8.1 Operating Instructions

1.Set the thermostat to the lowest setting.

2.Turn off all electric power to the heater.

3.Do not try to light the burner by hand.

4.Turn off the manual gas valve in the heater supply line.

5.Wait five (5) minutes to clear out any gas. If you then smell gas, STOP! If you do not smell gas, go to the next step.

6.Open the manual gas valve in the heater supply line.

7.Turn on electric power to the heater.

8.Set the thermostat to the desired setting.

9.If the heater will not operate, See Section 8.2 and call your service technician or gas supplier.

8.2 To Turn Off Gas To Heater

1. Set the thermostat to the lowest setting.

2.Turn off all electric power to the heater if service is to be performed.

3.Turn off the manual gas valve in the heater supply line.

8.3 Sequence of Operation

1.When the thermostat calls for heat, the blower motor will energize.

2.When the motor approaches nominal running speed, the pressure switch closes and activates the ignition module which in turn initiates the purge.

3.The ignition module then energizes the spark igniter.

4.When sparking begins, the gas valve is energized.

5.If a flame is detected, the gas valve remains open. When the call for heat is satisfied, the system con- trol mechanism de-energizes and the gas valve is turned off.

6.If no flame is detected, the gas valve is closed, and a purge period begins. After the purge period, the ignition module energizes the spark igniter and the gas valve. If a flame is still not established, a third and final purge/ignition sequence is begun. After three failed attempts, the system control mecha-

nism will lock out for a period of one hour or until the unit is reset. Reset is accomplished by remov- ing power from the heater for at least five seconds.

7.With a three-try module, when the flame is estab- lished and then lost on the first or second trial, the gas valve will automatically turn off. A purge and trial for ignition will then occur.

8.4 Testing

Establish that a satisfactorily purged gas supply and an electrical supply is available to the heater.

With the gas supply turned off at the gas valve, and the electrical supply isolated by switching off at the local switch and removing the appliance electrical plug, open the control chamber secured by the four screws. Remove the sealing screw from the outlet pressure tap with a 3/16" Hex Key Allen Wrench and install a test tap and hose. Remove the cover cap from the regulator screw with a straight slot screw- driver through the top hole of the burner. (See Figure 33).

Turn on appliance gas valve and connect appliance electrical plug. Ensure that the timer or thermostat, if fitted, is set to call for heat. Switch on power at the local switch. If necessary, the sequence as described above, in the first and second paragraphs, should take place. If not, refer to detailed fault finding sequence. When flame is established, check the gas pressure reading and adjust if necessary. See data label or Page 8, Section 2, for required gas pressure setting.

Check the gas pressure at the outlet of the gas valve to ensure minimum pressure. See Page 8, Section 2.9, for required gas pressure settings.

Switch off the electrical supply (shutting down the heater), remove pressure gauge and refit plug at out- let pressure tap, ensuring a tight gas seal. Replace cap and regulator screw. Close burner side cover.

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