Camus Hydronics MFH060 Installation, Operation And Service Manual page 53

Blocked Flue Switch
The normally-closed blocked flue switch has been preset at the factory according to Table 9. In cases
where the heater loses the flame signal as it approaches high-fire adjustment to the blocked flue switch
may be necessary. The following description is for the benefit of the start-up technician should minor
adjustment be required.
1) Remove the lower front jacket panel
2) Reduce sensitivity of blocked flue switch by turning the flat screw ¼ turn clockwise.
3) Observe the operation of the burner as it approaches high fire with the fan inlet 1/3 blocked, if the
heater continues to operate at high fire the switch has been correctly set. If not, repeat steps 2
and 3.
4) Re-install lower front jacket panel
Differential Air Switch
A differential air pressure switch is provided to prove air flow at minimum fire conditions
1) Remove the lower front jacket panel
2) Insert allen key into the switch located on the combustion chamber door
3) Reduce sensitivity of differential air switch by turning the hex screw ¼ turn counter-clockwise.
4) Re-install lower front jacket panel
Ignition System Safety Shut-Off Device
After initial fill while the main burner is firing, shut off gas to the pilot and clock the time taken for the main
gas valve to shut down. If the safety control is functioning properly, power to the gas valve will be shut off
within 4 seconds of the pilot gas being shut off. If shut down takes longer, ignition control or gas valve
may be defective. If shutdown does not occur it is possible that the main gas flow is generating a signal at
the pilot in which case the pilot shall not recycle with the pilot gas off.
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