Page 36 LXi
™
Pool/Spa Heater Installation and Operation Manual
Make sure the pool fi lter is clean before mak-
ing any pressure switch adjustment. A dirty fi lter will
restrict the water fl ow and the pressure switch cannot be
adjusted properly.
To adjust the pressure switch, refer to Figure 31
and proceed as follows:
1. Set the heater control to the "OFF" mode.
2. Remove the side panel above the front header to
access the water pressure switch.
3. Start the fi lter pump and confi rm by means of a
voltmeter that the pressure switch closes (if the
switch fails to close, replace it with a switch that
has a lower minimum setting).
4. Set the heater control to either POOL or SPA.
Heater should start.
5. Pry out the top cap on the pressure switch.
6. Use a 7/32" Allen wrench to turn the adjustment
screw very slowly clockwise until the heater goes
off.
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 fi lter pump
OFF. The heater fan will continue to run but the
burners should shut off immediately. If they do
not, restart the fi lter pump and repeat
Steps 6 and 7. Check the adjustment again.
9. Return the pool temperature control to the desired
temperature.
It may be necessary to repeat these steps to get a
proper setting. The switch must be set so that the heater
will not fi re unless the pump is running. If a proper
setting cannot be reached, contact the factory service
department.
7.8 Temperature Rise
The LXi pool and spa heaters have an internal by-
pass which accommodates a wide range of water fl ow.
The bypass is easily adjustable to change the tempera-
ture rise for optimum performance and length of heater
life. The bypass assures constant heat exchanger fl ow
even though fl ow through the fi lter system will vary
depending on how dirty the fi lter is.
For most installations, an external bypass valve
is not needed in the heater water piping. This is due to
the large size of the heater's internal bypass valve. If the
pump fl ow rate is known to exceed 125 gpm
(7.9 l/s), an external bypass may be needed to assure
proper heater operation.
Figure 32. Temperature Rise Measurement
BYPASS
ADJUSTMENT
SCREW
THERMOMETER WITH
PETE'S PLUG
®
Water fl ow should be confi rmed upon start-up of
the heater and in most servicing situations. If the fl ow
is not normal, corrections must be made to the pool
system. Flow is evaluated by determining the water
temperature rise through the heat exchanger.
Before checking the temperature rise, make sure
that the pool fi lter is clean and that gas supply and
manifold pressures are correct. If necessary, clean all
components of the fi lter system. Temperature rise is
measured in the return header of the LXi. To mea-
sure the temperature rise, turn off the fi lter pump and
remove the plastic plug protruding through the cabinet
on the return header side of the heater. (See Figure
32.) With the plug removed, install the special thread
adapter and Pete’s Plug
®
fi tting and insert a pocket
thermometer. A temperature rise measurement kit is
available through your Jandy distributor. See Section
11 of this manual for the correct kit number.
Pete's Plug
®
is a registered trademark of the Peterson Equipment
Company.
The internal bypass can be adjusted by means of
a screw on the right-hand side of the header. To adjust
the temperature rise to within the ranges specifi ed in
Table 7, proceed as follows:
1. If the piping system has an external bypass valve,
close it.
2. Set the heater's control panel to the "OFF" posi-
tion.
3. Start the fi lter pump.
4. After three minutes, note and record the ther-
mometer reading. This is the pool water tempera-
ture.
5. Start the heater by setting the control panel to
either POOL or SPA. Allow the heater to operate
for 5 minutes or more. Note and record the ther-
mometer reading. Subtract pool water tempera-
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