P/N 475114 Rev. F 8/2020
MASTERTEMP 125 Pool and Spa Heater Installation and User’s Guide
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SAFETY CONTROLS
AIR FLOW SWITCH (AFS)
The air flow switch (see Figure 35), is a safety device used to insure that the
combustion air blower (fan) is operating and has been designed to monitor the vacuum
(negative) pressure within the blower housing. The air flow switch is factory set and
is connected upstream of the ignition module. The ignition module does not operate
unless the air pressure switch and all safety switches are closed.
WATER PRESSURE SWITCH
WARNING
Hazardous pressure. Do not bypass the Water Pressure Switch or render
it inoperable.
The water pressure switch (see Figure 37). If the water flow is restricted,
the water pressure switch may prevent the burner from firing and cause the
“Service System”
light to go on. If the light remains on after the filter has
been serviced, have a qualified service technician check the system.
For deck-level heater installations, the Water Pressure Switch is factory
set at 0,2 bar (3.00 psi).
NOTE: See,
“
Below Pool Level Installation” on
page 5
. If the pressure switch is 0.3M (1 ft.) below or above the pool water
level, reset the switch so that it is open when the pump is off and closed
when the pump is running. Turn the star-wheel on the switch clockwise
( ) to raise setting (heater below the pool) and counterclockwise
( ) to lower the setting (heater above the pool - see Figure 6). Test the
switch after resetting.
NOTICE:
When the heater is mounted more than 1.5M
(5 ft.) above or 1.2M (4 ft.) below the deck level, a
Pressure Switch is no longer adequate. A Flow Switch
must be installed instead.
NOTICE:
Heater operation with incorrect Pressure
Switch setting may cause operation with no water
flow. Operation of the heater without sufficient
water flow may severely damage it
will void the
warranty
.
HIGH LIMIT SWITCH
A “High Limit”, is a safety device that opens the
electrical circuit and shuts off the heater based on a
water temperature set point within the “High Limit
Device”. The MasterTemp
125 heater has three (3)
high limit devices which are located on the main inlet
/ outlet header (see page 47 item 6).
Star Wheel
A reference scale is on
the back of pressure switch
Turn star wheel
clockwise
to
raise
pressure set point if pressure switch is
more than 1.2 m (4 ft) below water level
Turn star wheel
counterclockwise
to lower
pressure set point if pressure switch is more
than 1.5 m (5 ft) above water level
Figure 30.
1.2 m (4 ft)
1.5 m (5 ft)
Air Flow Switch
Water
Pressure
Switch
Figure 29.
Figure 35.
Figure 36.
Figure 37.
Section 2. Operation
