12.2 Maintenance
Procedures
(cont’d)
For location of controls,
see FIGURE 28, page 43.
12.2.13
Vent Temperature Limit Switch
The vent temperature limit switch is located on the discharge of the com-
bustion air blower (venter) and its purpose is to prevent the vent gas tem
-
perature from exceeding a temperature that will harm the PVC vent pipe.
If the vent temperature limit switch is activated, the cause must be deter-
mined and corrected before the heater is placed back into operation. Acti-
vation of the manually reset vent temperature limit switch could be caused
by one or more of the following:
Manifold gas pressure too high
The heat content of the fuel being burned is too high
Reduced circulating airflow due to dirty an/or plugged air moving
components
Excess dirt on the heat exchangers
Failed heat exchanger(s)
After the cause is determined and corrected, depress the red button on the
switch to reset it.
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12.2.14
Disconnect Switch
The disconnect switch is located in the sealed electrical box inside the con
-
trol compartment with the toggle on the rear of the heater.
If it is determined that the disconnect switch needs replacing, use only the
factory-authorized replacement part that is designed for the heater. Always
replace electrical box cover.
12.2.10
Door Switch
If it is determined that the door switch needs
replacing, use only a factory-authorized replace-
ment part that is designed for the heater.
12.2.12
Transformer
Use a voltmeter to verify that there are 24 volts output from the trans-
former. If the transformer is not functioning, it must be replaced. Use a
replacement transformer identical to the factory-installed model.
Disconnect
Switch
Vent Temperature
Limit Switch
Door
Switch
Transformer
12.2.11 Time Delay Relay
If it is determined that the time delay relay
needs replacing, use only a factory-autho-
rized replacement part that is designed for the
heater
Time
Delay
Relay
12.2.15
Vent/Combustion
Air System
Check the complete system at least once a year. Inspection should include
all joints, seams, concentric adapter box, inlet air guard or cap, and the
vent terminal cap. Clean openings. Replace any defective parts.
12.2.16
Condensate
Drain System
Check the condensate disposal system annually. Remove the condensate
traps and flush them with clear tap water to remove any sediment that my
have accumulated. Check to be certain the piping to the sanitary drain has
not been damaged. Check the sanitary drain to verify that it flows freely.
12. Maintenance and
Service (cont’d)
Form I-UEAS, Page 46
