Pressure Switch - Girard Products GSWH-2 Technical Manual

Pressure Switch

The pressure switch is the air proving device on the water heater. It is vital that the fan is operating before the board goes
into ignition mode.
The pressure switch contacts close as the air from the fan passes over the Petit Tube inside the blower housing. This creates a
suction on the hose that connects the fan housing to the pressure switch. This will pull the contacts of the pressure switch
closed.
E8: Air pressure switch:
Air pressure switch not detected for 7 sec. before ignition or is cut-off for 2 sec. during normal operation. This failure may be caused by a faulty motor or
a blockage in the air supply or in the exhaust system.
An E8 fault is read when the control board does not see the pressure switch close. Remove the mounting screws of the
pressure switch to get better access to the components and eliminate the following before replacing the pressure switch.
1. Check for integrity and connections of the hose.
2. Check the wire connections on the board and the pressure switch.
3. Check the integrity of the Petit Tube in the blower housing. Ensure the mounting nut is not loose and the standpipe is
not twisted out of position. The petit tube should be facing away from the blower wheel. (works with suction)
4. Check for debris in the open pipe of the pressure switch.
5. Once the above conditions have been eliminated remove the pressure switch completely. With the pressure switch
removed you can apply suction to the port the hose is attached and confirm with a continuity test if the switch is not
actuating.
Pressure
switch
side view
Pressure
switch
mounting
Pressure
switch
Hose
Pressure
switch
Petit
Tube
Pressure
switch Petit
Tube Nut
15