Raypak 131 Service Instructions Manual page 17

55ºC Outlet High Limit - A normally closed temperature sensitive switch mounted on the
outlet header connection which will open circuit power to the gas valve if an over
temperature condition occurs. If the outlet water temperature reaches 55ºC or more, the
55ºC outlet high limit contacts will open circuit shutting down the gas valve and burner.
The 55ºC outlet high limit contacts will automatically close when the detected water
temperature drops below 45ºC at which time heater operation will automatically continue.
Water Pressure Switch - A normally open adjustable pressure sensitive switch utilised to
detect the presence of water flow (pressure) in installations where the inlet/outlet pipe work
is less than 1500 mm above or below the water level of the pool. For installations which
exceed this range an external flow switch must be installed (refer to „Water Flow Switch‟
on page 17 for more information).If the correct water flow (pressure) is present, the
pressure switch contacts will close enabling operation of the gas valve/ignition system
(refer to page 42 for pressure switch adjustment procedure).
Water Flow Switch - A normally open adjustable flow sensitive switch utilised to detect
the presence of water flow in installations where the Inlet/Outlet pipe work is greater than
1500 mm above or below the water level of the pool. For installations where the
Inlet/Outlet pipe work is less than 1500 mm above or below the water level of the pool a
pressure switch must be installed (refer to „Water Pressure Switch‟ on page 17 for more
information). If correct water flow is present the flow switch contacts will close enabling
operation of the gas valve/ignition system (refer to page 42 for flow switch adjustment
procedure).
Water Temperature Probe - A thermistor located on the inlet header manifold which is
utilised to detect the water temperature entering the heater (pool/spa water temperature).
The temperature probes resistance value will change according to the detected
temperature. The control board detects the changing resistance value and utilises this
input to display the water temperature and to determine if a call for heat is required. Refer
to page 40 for water temperature probe test procedure and temperature/resistance chart.
Solar Collector Water Temperature Probe (optional) - A thermistor located on the solar
collector (if fitted) which is utilised to detect the water temperature at the solar collector(s).
The solar collector temperature probes resistance value will change according to the
detected temperature.
The control board will monitor the water temperature at the solar collector and if the water
temperature at the solar collector (as detected by a solar collector water temperature
probe) is above the inlet water temperature (as detected by the pool heaters water
temperature probe), the control board will activate a solar diverter valve (if fitted) that
allows the water from the solar collector to be used as inlet water to the pool heater. Refer
to page 40 for water temperature probe test procedure and temperature/resistance chart.
Control Board (Controller) - An electronic PCB which monitors the inlet water
temperature and controls the water temperature by energising and de-energising the
ignition module. The control board has an LCD display with push buttons which allows for
user interface. The control board can also communicate via an electric interface board
(EIB) to provide additional switching of remote components i.e. pool lighting, garden
lighting and/or water fountains.
A remote controller is also available as an option.
TM018 Raypak 131 Type A Pool & Spa Heaters REV: A
17
D.O.I: 8/04/2009
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