Water Pressure Switch Adjustment; Temperature Rise - Jandy LG125 Installation And Operation Manual

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Figure 19. Pressure switch adjustment.
IMPORTANT: The temperature controls
cannot be calibrated in the field. If the control is faulty,
shut down the heater by following the procedures in
Section 7.3 and have a qualified service technician
replace the control. DO NOT use the thermostat
switch to completely shut down the heater.

7.5 Water Pressure Switch Adjustment

CAUTION
The water pressure switch should be adjusted
to turn the heater off when the pump is off.
Setting the switch to close at too low of a flow
can damage the appliance. Adjust the switch to
turn the heater off, not on.
The pressure switch is preset at the factory for
activation at 2 psi (14 kPa). Adjust the pressure switch
only if any part of the filter system piping is 3 feet
(0.91 m) or more above the top of the heater jacket.
Do not adjust the pressure switch if the heater is
installed more than 15 feet (4.57 m) below or 6 feet
(1.83 m) above the pool surface. Consult your local
Jandy representative for recommendations.
On some installations, the piping from the heater
to the pool is very short. The back pressure could be
too low to trigger the pressure switch. If this happens,
it may be necessary to install a directional fitting or
elbows where the return line enters the pool. This will
increase back pressure enough for the heater to operate
properly.
Make sure the pool filter is clean before making
any pressure switch adjustment. A dirty filter will
restrict the water flow and the pressure switch cannot
be adjusted properly. To adjust the pressure switch:
1. Set the control panel rocker switch to the OFF
position (see Figure 18).
2. Set the Pool temperature control to the Max
position.
3. Turn filter pump on. If a two-speed pump is
used, make sure it is at high speed.
NOTE: If using a two-speed pump, the heater
should not be allowed to fire on low speed.
4. Set the rocker switch to ON. Heater should start.
5. Pry out the top rubber dust plug on the top of the
pressure switch.
6. Use a 7/32 inch (5.55 mm) Allen wrench to turn
the adjustment screw very slowly clockwise until
the heater goes off (see Figure 19).
7. Slowly turn the pressure switch adjustment
screw counterclockwise one-quarter turn. The
heater should come back on.
8. Check the adjustment by turning the filter pump
OFF. The heater should shut off immediately. If
it does not, restart the filter pump and repeat
Steps 6 and 7. Check the adjustment again.
9. Return the pool temperature control to the
desired temperature.

7.6 Temperature Rise

The automatic flow control valve (see Section
5.2) maintains the proper flow through the heater at
rates up to approximately 125 gallons per minute
(GPM) (475 liters per minute [LPM]).
A temperature rise test confirms proper water
flow through the heater. The temperature rise is the
difference between the temperature of the pool or spa
water before and after heating, as measured in the
header. Perform the following temperature rise test
when the installation is complete:
1. Make sure the pool filter is clean.
2. Set the rocker switch on the temperature control
panel (see Figure 18) to OFF.
3. Turn the filter pump OFF.
4. Remove the drain plug located on the inlet/outlet
header of the heater and replace it with a Pete's
plug (see Figure 15).