Model LD Pool and Spa Heater
Page 31
These procedures require a Volt-Ohm
meter with a minimum 0-250VAC voltage range,
and 1-1000 Ohm resistance range. Figure 23
shows the power and control circuits and where
to take measurements. Location numbers in
circles have been added, and will be referenced
in the following sections.
The electrical power supply can be checked with
the heater not set to fire. All other procedures need to
be checked with power correctly supplied to the
heater, all external devices set so that the heater is
allowed to fire and the heater's thermostat set so that
there is a call for heat.
As stated at the beginning of the manual, some of
these procedures are hazardous. Only a qualified
service technician should service the heater.
10.4.1 Electrical Power Supply
The electrical components of the LD heater is
designed to operate with supply voltage ranging from
98V to 126V at 60 Hz if connected to a nominal 115
volt power supply, or 196V to 253V at 60 Hz if
connected to a nominal 230 volt power supply. Mea-
sure supply voltage at the power supply leads where
they enter the heater (identified as points A, B and C
on the wiring diagram in Figure 23.). Use the voltages
in Table 12 to verify that the correct voltage is sup-
plied to the heater.
If no voltage is present, correct this external
power supply problem to the heater. Circuit breakers,
time clock settings or similar devices may be the
problem. Voltage outside of the above ranges may be
due to poor wiring, poor connections, other loads such
as air conditioning compressors or to an electric utility
company problem. Arrange for correction of the
voltage as appropriate.
When you are sure that the voltage supplied to
the heater is correct, check the voltage being supplied
to the transformer by the power terminal strip. This
can be done by measuring the voltage between the
wires of the four primary taps on the transformer.
These points are designated as test points D, E,
F, and G on Figure 23. The voltages measured be-
tween any two of these four points will be determined
by the voltage supplied to the transformer (see Table
13 for expected voltages).
If the voltages measured do not fall within the
limits shown in Table 13, then there is a problem with
the power supply circuit board and the board must be
replaced.
10.4.2 Controller
The controller must be operational in order to
check the control circuits of the heater. The filter
pump must be running to during the remainder of the
troubleshooting procedure.
10.4.3 Control Circuit Troubleshooting
The heater controls are arranged in two 24V
60Hz circuits with the operating and safety controls
arranged in a series circuit.
Troubleshooting is done by probing for voltage
between the common and various points in the circuit
to determine which component is preventing operation.
Check points are indicated on Figure 23. The red lead
of the meter should be attached to the common tap on
the secondary side of the transformer and may be left
there throughout most of the procedure.
The recommended procedure steps through each
circuit in a sequential way, and each section assumes
that components from all previous sections have been
tested and are operational. However, verifying voltage
at any of the numbered points in that circuit confirms
that all prior components of the circuit are operational.
1.
Point D is the location at which the white wire with the black
trace is connected to the transformer.
2.
Point E is the location at which the white wire with the red trace
is connected to the transformer.
3.
Point F is the location at which the red wire is connected to the
transformer.
4.
Point G is the location at which the black wire is connected to
the transformer.
Table 13. Voltage Supplied To Transformer
1.
Point A is the ground connection on the heater.
2.
Point B is the location at which the red power lead is connected
to the power terminal strip.
3.
Point C is the location at which the black power lead is
connected to the power terminal strip.
Table 12. Supply Voltage Measurements
MEASURE
EXPECTED
EXPECTED
BETWEEN
VOLTAGE WITH
VOLTAGE WITH
THESE
230V SUPPLY
115V SUPPLY
POINTS
A and B
98 - 126 Volts
0
A and C
98 - 126 Volts
98 - 126 Volts
B and C
196 - 253 Volts
98 - 126 Volts
MEASURE
EXPECTED
EXPECTED
BETWEEN
VOLTAGE WITH
VOLTAGE WITH
THESE
230V SUPPLY
115V SUPPLY
POINTS
D and E
0
98 - 126 Volts
D and F
98 - 126 Volts
98 - 126 Volts
D and G
98 - 126 Volts
0
E and F
98 - 126 Volts
0
E and G
98 - 126 Volts
98 - 126 Volts
F and G
196 - 253 Volts
98 - 126 Volts