2 User Manual

18
Service Manual
Combustion Air Shutter Adjustment
This pool heater uses a fan assisted combustion process. The fan
air shutter is factory preset and should not need adjusting in
most cases. If adjustment is required, the fan air shutter may be
manually adjusted to a dimension specified for each model (see
Table 2B).
Follow the steps below to adjust the fan air shutter if the pool
heater does not function properly or a continuous low air
condition is observed:
1. Check for proper installation and draft in the venting
system. Correct as required.
2. Remove the upper left access door (FIG. 2-6).
3. Turn the power switch to the “OFF” position.
4. Turn the gas valve switch to the “OFF” position.
5. Use a ruler to measure the distance from the base of
the fan to the end of the air shutter (FIG. 2-7).
Compare this distance to the specified “A” dimension
for the pool heater in Table 2B.
6. Turn all gas valve knobs and the manual gas cock to the
“OFF” position.
7. Locate the air pressure switch located on the left side
panel. Trace the hose from the air pressure switch to the
chamber pressure barb located in the top of the upper
chamber. Remove the hose from the chamber pressure
barb and connect the hose from the manometer or
magnahelic to this barb to measure the air pressure in
the front chamber.
8. Turn the power switch to the “ON” position.
9. Set the thermostat to call for heat. The fan will start.
10. While the combustion air fan is running for the prepurge
cycle and the pressure in the front chamber stabilizes,
record the pressure in the front chamber. This pressure
will be used to calculate the net manifold pressure.
11. Turn the power switch to the “OFF” position.
12. Remove the manometer or magnahelic hose from the front
chamber barb and reinstall the hose from the air pressure
switch to the barb.
13. If the pressure switch still exhibits failures, check the
differential air pressure measurement.
Figure 2-6_Combustion Air Fan Location
2
Maintenance
"A"
Figure 2-7_Combustion Air Fan with Air Shutter “A”
Dimension
TABLE - 2B
AIR SHUTTER
ADJUSTMENT OPENING
Model
“A” Dimension
Opening
Chamber
Pressure
ER152 1 1/4" 1.4"
ER202 1 1/4" 1.4"
ER252 1 3/8" 1.4"
ER302 1 9/16" 1.4"
ER402 1 3/4" 1.4"