FLAME ROLL-OUT SAFETY SWITCH
Atmospheric
heaters
are
equipped with a thermal cutoff
device to prevent flame roll-out
in the event the heat exchang-
er becomes blocked. This is a
"single-use" type fusible link or
thermal fuse, that must be
replaced when disabled by an
over-temperature condition, caused by excessive
restriction in the heat exchanger flue passage.
HIGH LIMITS
The heater is equipped with two automatic high limits.
Both are located in the inlet/outlet header. Both are set
to open at 135°F.
38
1. Make sure the pool filter is
clean before adjusting the
switch.
2. Set the heater control to the
OFF mode.
3. Turn the filter pump on and
confirm that the pressure
TWO-SPEED PUMPS
In some cases, the flow on the low-speed is insufficient
to operate the heater. This is apparent when the water
pressure switch cannot be further adjusted or if the
heater makes banging noises or shuts off on high limit.
In these cases, the pump must be run at high speed
when heating the water.
PRESSURE SWITCH
ADJUSTMENT RANGE
CAUTION:
Do not operate the heater without the
function of a properly adjusted water pressure switch
or flow switch.
5 FT.
MAX
POOL OR SPA
MAY REQUIRE ADJUSTMENT
FOR LOWER PRESSURE
MAY REQUIRE ADJUSTMENT
FOR HIGHER PRESSURE
5 FT.
MAX
switch is closed (use a multimeter to check). If the
pressure switch fails to close, either the switch set-
ting is too high or not enough pressure is being
supplied by the filter pump.
NOTE:
If heater is installed outside of the limits
shown, a higher pressure rated (11 psi) switch may be
used. A flow switch, mounted and wired adjacent to the
heater, may be used in place of the factory-mounted
pressure switch. See Parts List (page 52) for 11 psi
water pressure switch.
WATER PRESSURE SWITCH
The water pressure switch ensures that the heater
operates only when the filter pump is in operation. It is
located on the inlet/outlet header. It is factory set at
1.75 PSI for deck-level installations. When the heater
is located below the level of the spa or pool, it may be
necessary to adjust the pressure switch to compen-
sate for the no-flow static head. If it is necessary to
adjust the water pressure switch, utilize the following
procedure:
WATER PRESSURE SWITCH ADJUSTMENT
Adjustment
Knob
TIME CLOCK/FIREMAN’S SWITCH
4. Turn the heater ON.
5. Manually turn the pressure adjustment knob clock-
wise until the heater shuts off. (A flat screwdriver
may be necessary if knob is too tight.)
6. Slowly turn the adjustment knob counter-clockwise
until the heater calls for heat again.
7. Turn an additional 1/2 turn counter-clockwise.
8. While the heater is running, check the adjustment
by turning the pump off and on several times. The
burners should shut off immediately when the
pump is turned off. If it does not, repeat the above
steps until proper operation is observed.
To operate the heater with a time clock, connect the
timer to the fireman’s switch connection in the heater’s
wiring. The time clock should be of the dual switch
type and set to shut off the call for heat to the pool
heater 15 to 20 minutes prior to shutting down the pool
pump. On millivolt heaters the fireman’s switch con-
nection is a wire nut located in the Violet/Black wiring
between the manual toggle switch and the gas valve.
For AFT heaters the fireman’s switch connection is
located on the 14-pin header connected to the digital
control board. Splice into the red wire jumper tagged
“Where necessary add “Fireman’s” switch circuit here”
to connect the time clock.
The fireman’s switch con-
nection on both millivolt and AFT heaters must be
a dry contact and must not supply power to the
heater. Powering the fireman’s switch connection
externally may damage the heater, and is not cov-
ered by warranty.
Millivolt heaters: Do not exceed 15ft of total wiring
using 14 AWG stranded copper wire rated for 105ºC
(221ºF) minimum.
AFT heaters: Do not exceed 50ft of total wiring using
18 AWG stranded copper wire rated for 105ºC (221ºF)
minimum.
NOTE:
When using a time clock, the heater will dis-
play “
Clock/ Fireman Sw
” when the fireman’s switch
is open, indicating that the time clock has shut off the
call for heat.
