Jandy Lite2 Installation And Operation Manual page 35

Model LD Pool and Spa Heater
point 10). Low or no voltage here means that the limit
is open and must be replaced. If voltage is detected at
test point 10, move the black lead of the meter to the
terminal of the water pressure switch where the white
wire from the high limits is connected (test point 11).
Less than 20 V at this point indicates that the wire
connecting the high limits to the water pressure switch
is faulty or poorly connected. Correct the problem or
replace the wire.
Note: The limit switches have different trip points,
and it is important that replacements are correct. The
150°F switch has a red dot on the top of the brass
fitting, and must be installed in the lower (horizontal)
well in the header. The 135°F switch has no dot and
must be installed in the upper (vertical) well in the
header.
10.4.5 Water Pressure Switch
If the meter shows at least a 20 V signal at test
point 11, move the black lead of the meter to the other
terminal on the water pressure switch (test point 12).
If there is no voltage, the pressure switch contacts
are open. This is almost always due to a water flow
deficiency, the most common one being a blocked water
filter or defective pump. However, sometimes it is due
to blockage of the copper siphon loop tube or mis-
adjustment of the switch. Investigate thoroughly,
referring to Section 7.5 on "Water Pressure Switch
Adjustment". If there is no problem with the pool
system or pressure switch adjustment, replace the
pressure switch.
10.4.6 Temperature Control
The temperature control consists of two major
components which must work together correctly for
the signal to be transmitted to the gas valve. The two
components are the temperature control panel and the
temperature sensor (thermistor). Use the following
procedure to check each component for functionality.
Check the temperature control as a complete
circuit before checking each component individually.
With the red lead of the meter still at test point 1, place
the black lead of the meter on the IND terminal of the
ignition control (test point 19) where the black wire
with a yellow trace is connected. Push the lead of the
meter into the plastic insulator of the connector along
side of the wire to make contact. If the meter shows
more than 20 V at the pressure switch (test point 12)
but not at test point 19, then one of the components of
the temperature control is faulty. Proceed with the
following sections to test the components.
10.4.6.3 Temperature Sensor
Remove the temperature control panel from the
bezel on the front of the heater to gain access to the
temperature sensor connections. The temperature
sensor is a 0-20,000 ohm thermistor. Set your ohmme-
ter to the 0-20K range. The meter readings will
depend on the temperature of the water in the header.
See the chart below for approximate readings at
various temperatures.
To test the temperature sensor, circulate water
through the heater for 5 minutes. Remove the tem-
perature sensor wires from the temperature control
board. Place one lead of the meter on each wire of the
temperature sensor (test points 17 & 18). Record the
reading. Measure and record the water temperature of
the pool near the inlet of the filter system. Find the
temperature in the chart that is closest to your tem-
perature reading of the pool water. Compare your
ohmmeter reading to the resistance number in the
chart. Remember that this is an approximate reading
and numbers may vary. If your reading is close to the
numbers indicated in the chart then the temperature
sensor is working correctly. Reconnect the wires to
the circuit board. If your reading is vastly different or
outside of the ranges shown the temperature sensor
should be replaced.
WATER TEMP.
IN HEADER
°F (°C)
50 (10)
60 (15)
70 (21)
80 (26)
90 (32)
100 (38)
10.4.6.2 Temperature Controller
First check the continuity of the yellow wire that
connects the controller to the gas valve. Remove the
wire from the terminal on the controller and the
terminal of the gas valve. Set your meter to read
ohms. Connect the black lead of the meter to one end
of the yellow wire (test point 15) and the red lead to
the other end of the wire (test point 16). If the meter
does not show zero ohms, replace the wire. Reconnect
the wire to the controller and the gas valve.
Now check the rest of the controller circuitry. Be
sure that the rotary switch is in the "POOL" or "SPA"
position. Place the red lead of the meter back on the
common terminal of the transformer (test point 1).
Place the black lead of the meter on the controller's
circuit board terminal (test point 13) where the black
wire from the pressure switch is connected. Less than
20 V at this point indicates that there is a problem with
the black wire that connects the pressure switch to the
controller. If at least 20 V is detected at test point 13,
move the black meter lead to the terminal on the
Page 33
APPROX. RESISTANCE
IN 1000'S OF OHMS
(kOhms)
19.9
15.5
11.9
9.3
7.3
5.8