OPERA
TION & CONTROLS
29
1. Water Pressure Switch - Verify adequate water flow and pressure (Clean Pool Filter/
Strainer basket).
2. High Limit Switches 1 and 2 Fault - Verify adequate water flow. Adjust (partially close)
external bypass. Check Unitherm Governor and internal bypass. Inspect for scale,
restricted flow.
3. Cabinet Limit Switch - Verify vent connection and all other sealing points of contact to
combustion chamber.
4. Differential Pressure Switch Fault - Check fan operation and fan power supply.
5. Air Pressure Switch Open - Check air inlet obstruction.
6. Vent Air Switch Open - Check vent obstructions.
2a
1
2b
3
Safety Circuit
5
4
6