Temperature Limiter Switches; Pressure Switch; By-Pass Valve - Hayward H150 Installation, Operation And Service Manual

SECTION 6. QUALIFIED TECHNICIAN - MAINTENANCE/SERVICING

Temperature limiter switches:

These controls will shut the heater off in the event that tem-
peratures outside the combustion chamber and inside the heater
cabinet become to hot. Possible causes for switch function in-
clude downdraft wind conditions or a blocked vent or drafthood.
Technician should evaluate unit to determine cause.
The left switch is an automatic reset type while right backup
switch is manual reset. See Figure 52. The manual reset switch
is resettable by removing the heater front door and then pressing
the center button on the switch which will reactivate it. Replace
the front door and restart heater.
To replace switch(s):
1. Turn pump, main gas valve and system switch off.
2. Turn electricity off on electronic ignition heater.
3. Remove heater front door.
4. Remove the two wires and screws securing the switch(s).
5. Replace with new switch(s) and reverse the above
procedures.
AUTOMATIC
RESET SWITCH
MANUAL
RESET SWITCH
Figure 52: Limiter Switches

Pressure switch:

The pressure switch (Figure 53) is preset at the factory for
deck level installations. When the heater is located below the
level of the spa or pool, the pressure switch may require an ad-
justment to compensate for the no-flow static head. The follow-
ing procedure is recommended when the switch needs adjust-
ment and/or is replaced:
1. Be sure the filter is clean before making the adjustment.
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2. With the pump and heater system switch on, turn the adjust-
ment dial on the pressure switch clockwise, until a click is
heard from the gas valve.
3. Turn the adjustment dial counterclockwise 1/4 turn.
4. Turn the pump off and on several times. The heater should
shut off immediately when pump is shut off. If the heater fails
to shut down with pump, repeat the steps above until the
switch is adjusted properly.
!
CAUTION: Do not operate the pool heater without the func-
tion of a properly adjusted pressure switch or flow switch.
To replace pressure switch:
1. Turn pump, main gas valve and system switch off.
2. Turn electricity off on electronic ignition heater.
3. Open front header drain and drain heat exchanger of
all water.
4. Remove heater front door.
5. Remove wires from pressure switch.
6. Using two 1/2" open end wrenches disconnect the pressure
switch from pressure switch tube.
7. Replace pressure switch and reverse above procedures. Use
new sealant on pressure switch threads before reinstalling.
8. Check for any possible leaks after start-up of unit.
Figure 53: Pressure Switch

By-pass valve:

The front header houses an automatic by-pass valve. The
valve provides proper water flow through the heat exchanger as
the filter system water pressure varies. The valve assembly con-
sists of a plunger, a spring and a shaft. The plunger glides along
the shaft as system water pressure compresses the spring. Very
high acid or chlorine concentrations may damage the valve parts
or very hard water may leave deposits on the shaft causing the
valve to stick. If the valve sticks open, very little water will pass
through the heat exchanger causing overheating and possibly
opening the high limit throughout the heat exchanger causing
condensation to occur. Either situation may result in insufficient
heating of the pool or spa.