Pomona, CA Clemmons, NC Nashville, TN
Tel: 908-355-7995 www.hayward-pool.com
USE ONLY HAYWARD GENUINE REPLACEMENT PARTS
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To replace a high limit switch:
1. Turn pump, gas supply, and heater power OFF.
2. Drain the heat exchanger of all water.
3. Unplug the high limit wires from the wiring harness.
4. Unscrew the high limit switch from the header.
5. Replace the high limit switch. Use new sealant on the high limit switch threads before reinstalling.
6. Reverse the above procedure to install the high limit switch.
EXHAUST GAS TEMPERATURE LIMIT:
The exhaust gas temperature limit monitors the
fl
ue gas temperature above the heat exchanger and trips if
temperature rises high enough to indicate that the heat exchanger has been damaged and is no longer transfer-
ring heat to the pool water effectively. If this limit trips, effort must be made to rectify the situation that has
damaged the heat exchanger. This is generally due to low water
fl
ow, poor water chemistry, or a combination
of these and other factors. Replace the limit as well as the heat exchanger before operating the unit again.
Running the unit without replacing the heat exchanger after this limit trips could damage the entire unit and
will not be covered by Hayward’s warranty.
To replace the exhaust gas temperature limit:
1. Turn pump, gas supply, and heater power OFF.
2. Remove the top jacket,
fl
ue transition top cap, and heat exchanger cover (see Figure 02).
3. Unplug the two wires from the exhaust gas temperature limit located in the
fl
ue collector panel above
the middle of the header.
4. Unscrew the (2) screws securing the limit to the panel and remove the limit and gasket.
5. Place the new limit and gasket in place and reverse the above steps to complete the procedure.
THERMISTOR:
The thermistor monitors the return water temperature. See Figure 18.
To replace the thermistor:
1. Turn pump, gas supply, and heater power OFF.
2. Drain the heat exchanger of all water.
3.
Remove the front access panel. (See Figure 02)
4. Unplug the thermistor connector from the ignition control board.
5. From outside the heater, pull the thermistor leads out of the control box and through the hole in the
heater chassis.
6. Unscrew the thermistor from the inlet side of the header.
7. Replace the thermistor. Use new sealant on the thermistor threads before re-installing.
8. Reverse steps above to complete the procedure.
WATER PRESSURE SWITCH:
The water pressure switch (Figure 18) is preset at the factory for most typical, deck level installations.
When the heater is located above or below the level of the pool or spa, the pressure switch may require
adjustment to compensate for the change in static head pressure. If adjustment is needed, the procedure is
detailed in Section III, under Water Pressure Switch Test / Adjustment Procedure.
ATTENTION:
Do not operate the pool heater without the function of a properly adjusted pressure
switch or
fl
ow switch.
To replace the pressure switch: