Transformer; Blower; Pressure Switch; Gas Valve - Pitco AG14S Service Manual

Transformer:

Transformers are multiple input voltage, 24 volt out-
put voltage and can be checked by reading the input
and output voltages.

Blower:

Check the voltage between the wires going to the
Blower. If 120 VAC is found and the Blower is NOT
turning it is defective.

Pressure Switch:

As the blower speed rises the amount of vacuum on
the suction side of the pressure switch rises past ap-
proximately 1.3" WC (0.325 kPa) the Presssure
Switch will close. When the vacuum falls below ap-
proximately 0.8" WC (0.2 kPa) the Pressure Switch
will open. With the Blower running, check the IN
and OUT voltage of the Switch. If 24VAC can be
found on one side but NOT the other the Pressure
Switch is defective.

Gas Valve:

The Knob should be in the ON position. Check for
24VAC between the terminals marked MV and MV/
PV and between PV and MV/PV. If voltage IS found
between both of these connections and the Gas Valve
does not open the Gas Valve is defective. If voltage
is NOT present at both of the coils on the Gas Valve,
troubleshoot and repair the machine until voltage IS
present at both coils, retest the Gas Valve as previ-
ously described.
Ignition Control Modules:
When the Ignition Control Module is supplied with
24 VAC from the temperature control system at the
TH terminal it will send a signal to the Ignitor which
will begin to spark. At the same time the Ignition
Control Module will also have a 24 VAC output sig-
nal on the MV terminal. The Ignition Control Mod-
ule will cause the Ignitor to spark for 10 seconds and
and then look for a flame sense signal, if it does not
receive a flame sense within 10 seconds signal it will
"Lock Out".
Ignitors:
When an Ignitor is supplied with power and does
NOT spark the Spark Gap should be checked.The
distance between the Ignitor and the Ground post
should be approximately 1/8" ± 1/32".
If the Ignitor is sparking but the Burner does not light,
check for a gas supply and make sure the Ignitor is
located in the correct position as shown in the draw-
ing.
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