XG-Fan Powered Air Terminals Rev 2
8
Specific Electric Heater Troubleshooting Procedures
(Cont.)
:
Problem
Cause
Solution
Manual Safety Reset
Switch is bad
1.
Allow the duct temperature to cool down below 90º F.
2.
If the heater still does not energize, perform the following.
3.
On heaters with the manual safety reset switch connected in the
backup contact circuit, jumper out the manual safety reset switch.
4.
If the backup contractor now engages, contact the factory for a re-
placement manual safety reset switch.
5.
If the backup contractor fails to engage, there is a problem in the
backup contractor holding coil.
6.
Use an ohmmeter to check continuity of the holding coil on the back-
up contractor.
7.
If bad, contact factory for replacement backup contractor.
Insufficient air flow
across the electric heat-
ing elements
1.
Then minimum allowable air flow across the heating elements is 70
CFM/kW.
2.
Unless this recommended minimum air flow is met, the leaving air
temperature of the heater will be greater than the safety reset switch-
es limits. This will cause nuisance tripping of the safety reset switch.
3.
Reset the minimum air flow across the heating elements during a call
for heat at 70 CFM/kW.
Warning:
On all troubleshooting that requires working inside the heater casing, disconnect the power first!
Jumpers used for diagnostic purposes should be removed before returning the heater to normal operation.
