Hayward H-Series Millivolt Na Mv Pool Heater All models English - Page 34

SECTION 6. QUALIFIED TECHNICIAN - MAINTENANCE/SERVICING Temperature limiter switches: These controls will shut the heater off in the event that temperatures outside the combustion chamber and inside the heater cabinet become to hot. Possible causes for switch function include 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. T urn pump, main gas valve and system switch off. 2. T urn electricity off on electronic ignition heater. 3. R emove heater front door. 4. R emove the two wires and screws securing the switch(s). 5. R eplace with new switch(s) and reverse the above procedures. 2. W ith the pump and heater system switch on, turn the adjustment dial on the pressure switch clockwise, until a click is heard from the gas valve. 3. T urn the adjustment dial counterclockwise 1/4 turn. 4. T urn 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. T urn pump, main gas valve and system switch off. 2. T urn electricity off on electronic ignition heater. 3. O pen front header drain and drain heat exchanger of all water. 4. R emove heater front door. 5. R emove wires from pressure switch. 6. U sing two 1/2" open end wrenches disconnect the pressure switch from pressure switch tube. 7. R eplace pressure switch and reverse above procedures. Use new sealant on pressure switch threads before reinstalling. 8. C heck for any possible leaks after start-up of unit. 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 adjustment to compensate for the no-flow static head. The following procedure is recommended when the switch needs adjustment and/or is replaced: 1. B e sure the filter is clean before making the adjustment. 32 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 consists 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.