Roberts Gorden Combat HF 30 v4, Installation, Commissioning, Service & User Instructions

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CABINET HEATER
2.4 Honeywell Combination Fan/Limit Thermostat
This is a dual function control and safety device:
1. Fan Thermostat. This automatically turns the fan ON and OFF during the heater operation controlled by the
leaving air temperature. It is fitted with a white manual override button which must be in its “pulled out” position for
automatic operation. In its “pushed in” position the fan(s) will run continuously.
2. Limit Thermostat. This protects the heater from overheating caused by a reduction of air flow over the heat
exchanger. It is a manual reset device and once operated prevents the heater restarting until reset.
To reset wait until the heater has cooled sufficiently then press in and release the red reset button. After operation of the
limit thermostat, efforts should be made to locate the problem causing its operation.
Note : IT IS ESSENTIAL THAT THE LINK SHOWN IN FIG. 2.3 IS REMOVED IN THE EVENT OF A REPLACEMENT
COMBINATION FAN/LIMIT THERMOSTAT BEING FITTED
Following replacement or adjustment, the limit thermostat setting must be re-sealed using a suitable paint spot seal.
For settings see Commissioning Section 5.1.2.1.
Fig. 2.3 Combination Fan/Limit Thermostat
2.3.8 Main Gas Valve (For models above 030)
Ten seconds from when the start gas is energised the main gas valves energise and the main flame expands from the
start gas. The control is now in its normal run position.
When the external controls are satisfied the control box turns off all outputs simultaneously and returns to rest position
for the beginning of the next sequence.
2.3.9 Fault Conditions
If at any stage the flame fails , the air pressure switch detects a loss of air pressure or a rise in combustion chamber
pressure ,then the control will go to ‘lockout’. The red light on the control box will glow and the control will need to be
manually reset before any further start attempt can be made.
For control sequence see Fig. 2.2.