Lochinvar GAS HEATER FOR COMMERICAL POOL APPLICATIONS - Manual (Page 28)

IIN NS ST TA AL LL LA AT TIIO ON N Continued
Figure 29 shows a typical pool heater gas train.
Figure 29 – Typical Pool Heater Gas Train Drawing
Combination Gas Valves
These pool heaters fire in a single stage of operation.
Note: This pool heater incorporates a “soft start” feature
which lights approximately half of the burners before lighting
the remaining burners. Each combination valve consists of a
gas regulator and two valve seats to meet the requirements for
redundant gas valves. The valve has a gas control knob that
must remain in the open position at all times when the pool
heater is in service. The gas control valve has pressure taps
located on the inlet and discharge sides of the valve. Manifold
pressure is adjusted using the regulator located on the valve. A
manifold gas pressure tap for each burner stick is located on
the discharge side of the valve.
The manifold pressure is preset at the factory and adjustment
is not usually required. If you must adjust regulator pressure,
follow the instructions under Gas Manifold Pressure
Adjustment, page 30.
Venting of Combination Gas Valves
The combination gas valve/regulator used on these pool
heaters is equipped with an integral vent limiting orifice per
ANSI Z21.78. The vent limiter ensures that the volume of gas
emitted from the valve in the event of a failed gas diaphragm
does not exceed the maximum safe leakage rate allowed by
agency requirements. Combination gas valve/regulators
equipped with integral vent limiters are not required to have
vent or relief lines piped to the outdoors.
Checking Gas Supply Pressure
Use the following procedure to check gas supply pressure.
1. Turn the main power switch to the “OFF” position.
2. Turn gas valve knobs to the “OFF” position.
3. Shut off gas supply at the field-installed manual gas cock
in the gas piping to the pool heater. If fuel supply is L.P.
gas, shut off gas supply at the tank.
4. Remove the 1/8" hex plug, located on the “inlet” side of
any gas valve. You may also use a tapping on the field-
installed main manual gas cock or gas piping. Install a
fitting in the inlet pressure tapping suitable to connect to a
manometer or magnahelic gauge. Range of scale should be
14" w.c. or greater to check inlet pressure.
5. Turn on gas supply at the manual gas cock, turn on L.P. gas
at the tank if required.
6. Turn the power switch to the “ON” position.
7. Turn the gas valve knobs to the “ON” position. Set the
temperature control to call for heat. See Operating
Temperature Control on page 40 for programming
instructions.
8. Observe the gas supply pressure as all burners are firing.
Ensure that inlet pressure is within the specified range. See
Connecting To Gas Supply, page 26 for minimum and
maximum gas supply pressures.
9. If gas pressure is out of range, contact gas utility, gas
supplier, qualified installer or service agency to determine
necessary steps to provide proper gas pressure to the pool
heater.
10. If gas supply pressure is within normal range, turn the
power switch to the “OFF” position.
11. Turn gas valve knobs to the “OFF” position.
12. Shut off gas supply at the manual gas cock in the gas
piping to the pool heater. If fuel supply is L.P. gas, shut off
gas supply at the tank.
Commercial Pool Heaters
28
Btu/hr Distance From Meter (in feet)
Input 0-50 51-100 101-200 201-300 301-500
500,000 1 1/4 " 1 1/2 " 2 " 2 " 2 1/2 "
650,000 1 1/2 " 2 " 2 " 2 1/2 " 2 1/2 "
750,000 1 1/2 " 2 " 2 " 2 1/2 " 3 "
990,000 2 " 2 " 2 1/2 " 2 1/2 " 3 "
1,260,000 2 " 2 1/2 " 2 1/2 " 3 " 3 "
1,440,000 2 1/2 " 2 1/2 " 3 " 3 " 3 1/2 "
1,800,000 2 1/2 " 3 " 3 " 3 1/2 " 3 1/2 "
2,070,000 2 1/2 " 3 " 3 " 3 1/2 " 4 "
TABLE-J
Suggested Gas Pipe Size for Single Unit Installations