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All installations and services must be performed by qualified service personnel.
38
Figure 22
: The CHB1/CDB1 furnace models are an in-shot burner design, which does not require an air
shutter adjustment (air shutters are not used) for proper flame characteristics. Burner box access cover must
always be secured with all screws in place and tightened before operating furnace.
E. FURNACE CHECKOUT PROCEDURE
Before any system of gas piping is finally put into service, it shall be carefully tested to assure that it is gas tight as
indicated in the manual.
NOTICE: All controls on the unit should be checked for proper functioning prior to the qualified service personnel
leaving the job site. Specifically the following should be checked:
With furnace in normal heating operation, check to make certain blower will start and stop automatically under
control of integrated fan control.
1. Check safety limit control as follows:
a. Shut off incoming power.
b. Block return air opening or disconnect blower motor leads.
c. Restore power to furnace.
d. Set thermostat above room temperature calling for heat.
e. When temperatures are reached in furnace at limit control setting with blower out of operation, burner
should shut off.
f. Shut off electrical power.
IMPORTANT: Remove blockage or reconnect blower motor and restore power.
2. Make certain thermostat will automatically start and stop furnace.
3. Block the flue pipe outlet gradually with a flat piece of metal, until the pressure switch functions shutting off the
main burners.
4. Block the PVC pipe inlet gradually with a flat piece of metal until pressure switch functions shutting off the
main burners.
IMPORTANT: Remove flue air inlet blockage when done.
5. Remove the blower compartment access door with the furnace operating. The door interrupt switch is in the 120
volt circuit and will shut down the entire system. Replace the blower door and the furnace start-up cycle will
begin.