Bradford-White Corp PDX Series Powered Direct Vent Gas Water Heaters Inlet Pressure Switch, See

PDX Series

PDX SERVICE PROCEDURE III

Pressure Switch Testing and

Replacement

Inlet Pressure Switch

WARNING

Testing120 volt potential exposure. Use caution making voltage checks to avoid personal injury.

Step 1. Position power switch on gas control to the “OFF” position.

Step 2. Remove the three screws (Phillips screw driver) from control access cover on blower assembly and remove cover (see photo 7).

Step 3. Remove wires from inlet pressure switch.

Exhaust

pressure switch

With steps 1,2 & 3

complete.

Use a multi-meter set to the ohms setting. With blower off, check across pressure switch terminals.

Are switch contacts closed?

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 pressure switch contacts remain closed with blower running with the switch in the vertical postition?

Y

7

Inlet pressure

switch

Check tubing and pressure

N tap on switch for blockage. Is there blockage?

					Y
				Clear blockage
		Y
					Y
	Check tubing and
				Is vent
N	pressure tap on		N			N
				system
	switch for blockage.

Is there blockage? blocked

N	Replace switch
	(see page 20)

Is vent system length

within vent table Y specifications listed on page 7

N

Reconfigure vent

system to be

Inlet pressure

switch wire

leads (found inside cover)

Y

See blower testing

(page 21)

Is blower OK?

N

Correct blower

Switch contacts are OK. See exhaust pressure switch testing (page 17)

compliant with

vent tables.

problem.

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