Specifications
Installation and Operation Manual
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Legacy™ Model LRZM Pool/Spa Heater
broken at any time, the gas valve is immediately
shut off and the heater stops ring. This voltage
is also used to activate the gas valve's pilot coil
which allows gas to ow to the pilot after the gas
valve knob is released.
4. Thermocouple - The thermocouple is a device
that senses if the pilot ame is hot enough to
ignite the gas fuel from the burner. If hot enough,
the main gas valve is allowed to open. If the
thermocouple does not sense enough heat from
the pilot ame (such as when the pilot is out),
then the thermocouple shuts off the gas valve to
the burners.
5. Limit Switches - Two (2) limit switches prevent
excessive water temperature - one (1) within the
heat exchanger and one (1) for water leaving the
heater. If either senses excessive temperature,
burner operation is interrupted.
6. Water Pressure Switch - This control senses
whether or not water is available to the heater
by measuring back pressure inside of the heat
exchanger. If the pool water pump fails or the
water lter is blocked, the pressure switch
prevents operation of the burner.
7. Roll-Out Switch (Fusible Link) - This is
a single-use switch which detects abnormal
temperature in the component vestibule. It is a
roll-out switch (fusible link) which is held to
the inner panel just above the burner tray by a
sheet metal bracket. Excessive temperature in
the component compartment, possibly due to a
blocked ue or ame roll-out, will cause the link
to fail. This opens the safety circuit which shuts
off the gas valve and shuts the heater down.
8. Vent Temperature Limit - This is a single-use
switch which detects abnormal temperature in the
vent system. It is mounted to the ue collector
assembly. Excessive temperatures will cause the
switch to open. Excessive temperatures can be
caused by inadequate water ow or a damaged
heat exchanger. The vent temperature limit will
open the safety circuit which shuts off the gas
valve and shuts down the heater.
This section describes procedures for check-
ing the pilot generator and control components of the
heater one at a time and in the order they appear in the
control circuit.
Pump must be running during the
troubleshooting procedure.
These procedures require a voltmeter with a
minimum 0-1000 mVDC range. Figure 25 shows the
pilot generator and control circuits, and where to take
measurements. Location numbers and letters in circles
have been added, and will be referenced in the follow-
ing sections.
As stated at the beginning of this manual, some
of these procedures are hazardous. Only a qualied
service technician should service the heater.
During the trouble shooting procedure, the lter
pump must be on, the pilot on the heater must be lit,
the ON/OFF switch on the heater must be in the ON
position and the control knob must be turned to the
maximum setting so that there is a call for heat. We
recommend turning the gas valve control knob to the
"PILOT" position to prevent the main burners from
ring throughout the procedure. Before starting the
procedure, be sure that the pilot has been lit for at least
two (2) minutes and that the pilot generator (thermo-
pile) is positioned correctly within the ame of the
pilot.
The pilot generator also operates the pilot coil of
the gas valve, allowing gas to ow to the pilot when
the gas valve knob is released from the pilot light-
ing position (see Section 8.3 "Lighting and Shutdown
Procedures"). If the pilot will not stay lit when the gas
valve knob is released, check the pilot generator output
as described in Section 11.4.2 and replace if necessary.
If the pilot generator output is sufcient, then check
the gas valve as outlined in Section 11.4.1.
The gas valve consists of two (2) separate
internal operating valves. The main valve supplies
gas to the main burners for heater operation. The pilot
valve supplies gas to the pilot when the pilot generator
activates the pilot coil.
If the pilot will not stay lit after following the
lighting instructions in Section 8.3, check for the
following:
• Pilot generator output
• Correct type of gas supplied
• Correct gas supply pressure
• Air in the gas line
• Pilot coil wire connections clean and tight
• Faulty thermocouple
If the pilot will not stay lit after checking the
items listed above, the pilot coil may be causing the
fault. Replace the gas valve.
If the main burners will not light after follow-
ing the lighting instructions in Section 11.4.2, check
the voltage reading between the PP terminal on the
gas valve (test point 1) and the TH terminal on the
gas valve (test point 17). If the meter shows less than
220mVDC then there is a problem with the pilot
generator, the sensors in the safety loop or the control
panel. Follow the trouble shooting procedure as
outlined in sections 11.4.2 through 11.4.7.
If the meter shows more than 220mVDC at test
point 17, then check for the following: