19
Condensing PV Series
19
Pressure Switch Testing & Replacement
Step 1. Position the power switch on the gas
control to the “OFF” position.
Step 2. Remove the three screws (Phillips screw driver) from the control access
cover on the blower assembly and remove the cover. Do not disconnect the
blower harness from the cover (see photo 1).
Step 3. Remove the 2 screws (Phillips screw driver) and carefully remove the
pressure switch to gain access to the wire lead connections (see photo 2).
With steps 1,2 & 3
complete, disconnect wire
leads from pressure switch.
Use a mutli-meter set to the ohms
setting. With blower turned off, check
across pressure switch terminals.
Are switch contacts open?
(no electrical continuity)
N
Y
Position gas valve power switch
to the “ON” position and adjust
thermostat to call for heat, this
will start the blower. Check with
multi-meter, do the pressure
switch contacts close with blower
running?
Y
Switch contacts are OK.
See Safety Circuit Voltage
Trace (page 30).
N
Y
Check tubing and
pressure tap on
switch for blockage.
Is there blockage?
Check tubing and pressure
tap on switch for blockage.
Is there blockage?
Y
N
Replace switch
(see page 19).
N
N
Clear blockage.
Is vent system
blocked?
Y
Is vent system length
within vent table
specifications listed on
pages 7 & 8?
See blower testing
(page 21)
Is blower OK?
Reconfigure vent
system to be compliant
with vent tables.
Correct blower
problem.
N
N
Y
Y
1
2
Remove 3 Phillips screws to
remove cover.
Remove 2 Phillips screws to
pressure switch.
Pressure switch wire leads.
WARNING
115 volt potential exposure. Use
caution to avoid personal injury.
