47
4. Remove the wires from the pressure switch.
5. Using two ½” open-end wrenches disconnect the pressure switch from the pressure switch tubing.
6. Replace the pressure switch. Use new sealant on the pressure switch threads before re-installing.
7. Reverse steps above to complete the procedure.
TRANSFORMER:
The transformer converts the fi eld supply voltage (either 240 VAC or 120 VAC) to a 120 VAC output for
blower and igniter power, and a 24 VAC output for powering the ignition control board, control circuits, and
gas valve. See Figure 21 for its location.
To replace the transformer:
1. Turn pump, gas supply, and heater power “OFF”.
2. Remove the front access panel. It is secured with (4) screws.
3. Disconnect all wires from the transformer leads.
4. Remove the (2) screws that secure the transformer to the control box.
5. Replace the transformer. Reassembly is the reversal of steps above.
BLOWER:
The blower provides the air that mixes with the gas at the
main burners for the combustion process. The blower oper-
ates during the pre-purge time (approximately 30 seconds) at
the beginning of each ignition cycle, during the entire time the
gas valve is open and the burners are fi ring, and for 30 sec-
onds after the valve gas closes. See Figure 21 and Figure 26.
To replace the blower:
1.
Turn pump, gas supply, and heater power “OFF”.
2.
Remove the front access panel (4 screws).
3.
Disconnect the blower wire harness from the ignition
control board.
4.
Disconnect the tubing from the hose barb on the
blower housing.
5.
Remove the blower air inlet plate from the blower (4
screws).
6.
Remove the blower from the air box co
ver (4 screws).
7. Reverse the above steps to reassemble the blower.
8. Be sure the blower outlet gasket is in place before proceeding.
er
Blower Air Inlet Plate
Blower
Air Box Cover
Blower Outlet Gasket
Figure 26: Blower
