Gas Manifold Pressure Adjustment - Lochinvar GAS HEATER FOR COMMERICAL POOL Installation And Service Manual

Commercial Pool Heaters
I I N N S S T T A A L L L L A A T T I I O O N N

Gas Manifold Pressure Adjustment

IMPORTANT: The gas valves are referenced to
the fan pressurized chamber by a hose
connected from the vent of the gas valve
regulator to the chamber pressure tap located on
the front inside portion of the jacket. Reference
the drawings in this section for component and
connection points for pressure measurement.
The procedure for connecting a manometer or
magnahelic must be followed to obtain actual net
manifold pressure for normal operation. A
manometer or magnahelic gauge legible in 0.1"
increments up to 10 inches w.c. is required to
check and adjust the manifold pressure. The
regulator cover screw on the gas valve must be
in place and tight at all times for the pool heater
to operate properly.
1. Remove the thumbscrew that fastens the control panel
access door and pull out the control panel.
2. Turn the power switch located in the lower left corner
behind the control panel access door to the "O" or "OFF"
position.
3. Remove the top front jacket access panels to access the gas
valves.
4. Locate the reference hose on the second gas valve which
goes from the vent fitting on the gas valve to a barbed
fitting on the deck of the pool heater (see Figure 31).
5. Remove the flexible cap from the barbed fitting on the
"tee" located in this line and hook one side of the
manometer, or (-) side of a magnahelic gauge, to this "tee".
Retain this cap for future use.
MANIFOLD
PRESSURE
4 4
3 3
2 2
1 1
0 0
BARBED
1 1
FITTING
CHAMBER
PRESSURE
2 2
3 3
GAS
VALVE
4 4
CONTROL
MANOMETER
KNOB
Figure 31 – Measuring Net Manifold Gas Pressure
Continued
CAP
PRESSURE
INLET
REGULATOR
ADJUSTMENT
(UNDER CAP SCREW)
1/8" HEX
MANIFOLD
PRESSURE
OUTLET
TAP
6. Remove the 1/8" hex plug from the manifold pressure tap
on the gas valve (see Figure 31). Retain plug for future
use.
7. Install a fitting in this tap that is suitable for connection of
a hose to a manometer, or (+) side of a magnahelic gauge
(see Figure 31).
8. Turn the power switch to the "I" or "ON" position.
9. Push the reset button(s) for the ignition control(s), if
necessary.
10. Set the temperature control to call for heat (see
Programming Temperature Control, page 41).
11. Once the pool heater is firing the manometer/magnahelic
will reflect the Manifold Gas Pressure. Compare this
reading to the respective value in TABLE-L, page 31 for
Natural Gas or Propane Gas.
12. If adjustment is necessary, remove the regulator cover
screw on the gas valve.
Note: If the gas valve under adjustment is located on a
manifold assembly monitored by an igniter, the pool heater
may shut down and recycle when the regulator cover screw is
removed. This is normal.
13. Turn the regulator adjustment screw "clockwise"
raise the regulator gas pressure.
adjustment screw "counterclockwise"
regulator gas pressure.
14. Replace the regulator cover screw and make sure it is tight
for proper operation.
15. Read the value on the manometer/magnahelic and compare
it to the values in TABLE-L.
16. Repeat this adjustment procedure for each gas valve as
necessary to adjust to the proper manifold gas pressure.
17. Remove hoses, replace and tighten plugs and caps when
complete.
18. Replace top front upper jacket access panels and control
panel door in reverse order.
19. If proper ignition and burner operation is not achieved after
checking gas supply pressure, see Cleaning and
Maintenance, page 49 for Combustion Air Fan
Adjustment. Follow the procedure to adjust the
combustion air fans as necessary.
30
to
Turn the regulator
to lower the