25
HEAT EXCHANGER REVERSAL PROCEDURE - STANDARD MODELS
1. Remove right and left side access panels
(Figure 1).
2. Disconnect wires at high limit, AGS (automatic gas
shut-off), and pressure switch on the in/out
header (Figure 2).
3.
Digital/AFT Models:
Remove the thermostat tem-
perature sensor by loosening the compression fit-
ting nut (Figure 3). Re-route the sensor to the left
side of the heater.
4.
Millivolt Models:
Remove the temperature sen-
sor bulb and retainer clip from the sensor well
(Figure 4). Re-route the sensor bulb to the left side
of the heater.
5. Remove (12) bolts holding the inlet/outlet and
return headers to the tube sheets. Clean off tube
sheet area where the gasket seats. Also clean off
the header and the gasket. Apply a non-petrole-
um-based lubricant to the gasket such as
AquaLube. Re-attach the headers to the opposite
sides, making sure they are installed in an upright
position (Figure 5).
Do not over tighten.
Torque
should not exceed 7 ft/lb.
6. Reconnect high limit, AGS, and pressure switch
wires.
7.
Digital/AFT Models:
Insert the temperature sen-
sor into the compression fitting, so that the sensor
is flush with the top of the fitting. Tighten 1/2 turn
past hand-tight.
8.
Millivolt Models:
Insert sensor bulb and retainer
clip into sensor well.
9. Allow for water flow through the heater and check
for leaks.
10. Re-attach access panels to the opposite sides.
For ASME Models call your factory representative.
Fig. #1
Fig. #2
Fig. #3
Fig. #5
Fig. #4
Summary of Contents for 206A
Page 28: ...28 WIRING DIAGRAM MILLIVOLT MECHANICAL THERMOSTAT ...
Page 29: ...29 WIRING DIAGRAM DIGITAL MODELS ATMOSPHERIC ...
Page 53: ...53 LO NOx HEATERS ...
Page 60: ......
