Installation manual

12.2 Maintenance
Procedures
(cont’d)
For location of controls,
see FIGURE 28, page 39.
12.2.13 Vent Temperature Limit Switch
The vent temperature limit switch is located on the discharge of the combustion
air blower (venter) and its purpose is to prevent the vent gas temperature from
exceeding a temperature that will harm the PVC vent pipe. If the vent temperature
limit switch is activated, the cause must be determined and corrected before the
heater is placed back into operation. Activation of the manually reset vent tempera-
ture 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 airow 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.
12.2.14 Disconnect Switch
The disconnect switch is located in the sealed electrical box inside the control
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 electri-
cal box cover.
12.2.12 Transformer
Use a voltmeter to verify that there are 24 volts
output from the transformer. 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
Transformer
12.2.11 Time Delay Relay
If it is determined that the time delay relay
needs replacing, use only a factory-authorized
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 ush them with clear tap water to remove any sediment that my have accumu-
lated. Check to be certain the piping to the sanitary drain has not been damaged.
Check the sanitary drain to verify that it ows freely.
12.0 Maintenance
and Service
(cont’d)
Form I-UEAS, Page 42