Pressure Switch Testing & Replacement - Bradford White LC2PV50H76N Service Manual

Condensing PV Series
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)
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).
Remove 3 Phillips screws to
remove cover.
1
Check tubing and pressure
N
tap on switch for blockage.
Y
Check tubing and
N
N
pressure tap on
switch for blockage.
Is there blockage?
115 volt potential exposure. Use
caution to avoid personal injury.
Remove 2 Phillips screws to
pressure switch.
2
N
Is there blockage?
Y
Clear blockage.
Y
Is vent system length
N
Is vent system
within vent table
blocked?
specifications listed on
pages 7 & 8?
Reconfigure vent
system to be compliant
with vent tables.
WARNING
Pressure switch wire leads.
Replace switch
(see page 19).
See blower testing
Y
(page 21)
Is blower OK?
N
Correct blower
problem.
Y
N
19
19