Hayward H-Series Millivolt Na Mv Pool Heater All models English - Page 33

SECTION 6. QUALIFIED TECHNICIAN - MAINTENANCE/SERVICING Control Locations: The following sections give a brief overview of the various heater controls and service/replacement procedures. The text describes the intended purpose of the controls. See Figure 50 for general location of the controls. Electrical wiring: ! NOTE: If it is necessary to replace any of the original wiring, it must be replaced with wiring suitable for 105°C {Style 1015 or 1230) or its equivalent. System Switch: A two-way "ON/OFF" rocker switch is provided for single thermostat heaters and a three-way "POOL/OFF/SPA" rocker switch is provided on dual thermostat heaters. To replace system switch: 1. T urn pump and main gas valve off. Turn thermostat to lowest setting. 2. T urn electricity off on electronic ignition heaters. 3. O pen control panel and remove wires from system switch. 4. P ress the ends of system switch in and remove from panel. 5. R eplace system switch and reverse above procedure. Temperature controls: Millivolt Heaters Millivolt heaters are manufactured with a mechanical thermostat models. To replace thermostat: 1. T urn pump, main gas valve and system switch off. 2. R emove thermostat knob, open control panel and remove right side access panels. 3. R emove the thermostat bulb from the front header. ! NOTE: Using needle nose pliers to pull out copper strip makes bulb removal easier. Pull thermostat capillary tube and bulb through the oval slot in the intermediate panel. ! CAUTION: Be careful not to crimp capillary tube as it could break from mishandling. 4. R emove wires from thermostat. 5. R emove screws that secure thermostat mounting bracket to control panel. 6. R eplace thermostat and reverse above procedures. Electronic Heaters Electronic heaters are manufactured with an integrated thermostat and ignition control that operates the heater. The replacement part is available as an assembly only. To replace control panel assembly: 1. T urn pump, main gas valve and electricity off. 2. U nplug wires from rear circuit board. 3. R emove four screws retaining the plastic bezel to the sheet metal. 4. P ull entire assembly through the front panel. 5. R eplace control panel assembly and reverse above procedures. High limits: The high limit is an automatically resetting safety device wired in series with the thermostat, pressure switch, temperature limiter switches, and main gas valve. See Figure 51. The pool heater is equipped with two automatic high limits. The limits are located on the front and rear headers ! CAUTION: The two limit switches have different tempera- ture settings (check Parts List). If the water temperature at the location of the limit should exceed the limit set point, the main gas valve will shut off gas supply to the burners. An erratic high limit is often an indication of a problem with water flow. Reduced flow may be caused by: 1. C logged filter or strainer. 2. E xcessive flow through the external bypass valve if one is used. 3. L ime scale accumulation in the heat exchanger. To replace high limits: 1. T urn pump, main gas valve and system switch off. 2. T urn electricity off on electronic ignition heater. 3. D rain heat exchanger of all water. 4. R emove side access panels. 5. R emove wires from high limits. 6. U nscrew the defective high limit. 7. R eplace the high limit and reverse above procedures. Figure 51: High Limit 31