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Page 47
ENGLISH
Installation and Operation Manual
|
Jandy
®
LXi
™
Model Pool and Spa Heater by Zodiac
®
10.5.3.4 Roll-Out (Fusible Link) Switch
To check the fusible link/air louver/field interlock
circuit, place the red lead at test point 6, see Figure
39. If 20-28 Volts AC nominal is not measured at this
point, either the controller or the two-pin wire harness
is faulty, or the water pressure switch is open.
If 20-28 Volts AC nominal is detected at test
point 6, then move the red lead of the meter to test
point 7. If 28 Volts AC nominal is detected, the circuit
is closed and working correctly.
If the proper voltage is not detected, either the
air box fusible link (152°C), vent box fusible link
(240°C), or field interlock has opened, or the wire har-
ness is faulty.
If no voltage is detected at test point 7, the roll-
out switch (fusible link) has failed. This indicates
higher than normal temperatures in the component
compartment (vestibule). Normal component com-
partment temperature is well below 149°C (300°F).
The roll-out switch (fusible link) is designed to fail at
temperatures above 152°C (305°F). Excessive temper-
ature might be due to a blocked flue or heat exchanger.
Clean the heat exchanger and clear the flue and vent of
any restrictions. Sometimes the roll-out switch (fusible
link) fails due to flame roll-out. Flame roll-out may be
caused by delayed ignition or downdrafting in windy
areas. Thoroughly investigate the causes for flame
roll-out and correct the problem when replacing the
roll-out switch (fusible link).
The vent temperature limit will fail due to
abnormal temperatures in the vent system. Excessive
temperatures will cause the switch to open. The vent
temperature limit is designed to fail at temperatures
above 464°F (240°C). Excessive temperatures can be
caused by inadequate water flow or a damaged heat
exchanger. Thoroughly investigate the causes for roll-
out switch (fusible link) failure and correct the prob-
lem when replacing the vent temperature limit.
10.5.3.5 Temperature Limit Switches
Circuit
Since the limit switches are not easily accessible,
the voltage can be checked at the two (2) legs of the
circuit at the controller. See test points 8 and 9 in
Figure 39.
Check the voltage at test point 8. If there is not
20-28 Volts AC nominal at this point, either the con-
troller or the two-pin wire harness is faulty, or one of
the two (2) safeties (water pressure or fuselink) before
it is open.
If 20-28 Volts AC nominal is detected at this
point, then move the red lead of the meter to test point
9, where the black wire from the 130°F (55°C) limit
enters the two-pin connector. If 20-28 Volts AC nomi-
nal is detected at this point, the devices in this circuit
are closed and the circuit is working properly.
If there is no voltage, one (1) of the limit switches
is open. This is normally due to excessive water
temperature, which should be thoroughly investigated
before replacement of limit switches. Excessive water
temperature may be caused by low water flow. Water
flow deficiency may be due to obvious problems such
as a defective pump or blocked water filter.
Alternatively, excessive water temperature may
be due to over-firing, or to a problem with the water
piping or the heater's internal bypass control. Over-
firing might be a result of an incorrect gas orifice or
supply of propane gas to a heater intended for natural
gas.
If there are no such fundamental problems, iden-
tify which of the switches is open. Limit switch access
is through the limit switch plugs on the side of the
heater to which water pipes are connected. Remove the
limit switch plugs from the bottom of the header and
gently remove the switches from the wells.
NOTE
The limit switches have different trip points,
and it is important that replacements are
correct. The 150°F (65°C) switch has a red dot
on the top of the switch, and must be installed
in the lower well in the header. The 130°F
(55°C) switch has no dot and must be installed
in the upper well in the outlet of the header.
Move the red meter lead to the terminal connec-
tion on the 150° switch that is connected back to the
controller. The voltmeter should read 20-28 Volts AC
nominal. No voltage here means that the two-pin wire
harness is bad and should be replaced.
If voltage is detected at this point, move the lead
to the other terminal of the switch. If the voltmeter
does not show voltage, then the 150°F (65°C) limit is
bad and should be replaced.
If the meter reads 20-28 Volts AC nominal, move
the lead to the terminal of the 130°F (55°C) limit that
is connected to the wire that jumps between the two
(2) limit switches. No voltage here means that the wire
assembly is bad and needs to be replaced. 20-28 Volts
AC nominal shows that the wire between the two (2)
limits is making a good connection.
Now move the lead to the other connection termi-
nal on the 130°F (55°C) limit. No voltage at this point
indicates that the limit switch has failed and needs to
be replaced. Voltage here would show that the limit is
good and that the two-pin wire harness may have a bad
connection. Replace the wire harness if necessary.
10.5.3.6 Blower Pressure Switch Circuit
The blower must be operating during the test pro-
cedure for the blower pressure switch. Start by check-
ing the voltage between test point 1 and the common
and normally open contacts of the air flow switch.
Leaving the black lead of the meter on test point
1, check the voltage at test point 11. If there is not
20-28 Volts AC at this point, the eight-pin wire har-
ness is faulty and must be replaced. If 20-28 Volts AC
is detected at this point, then move the red lead of the
meter to the Air Flow Switch NO contact.