PV500-2 06/10
4
Section 2
START-UP PROCEDURES AND OPERATION (con't)
CAUTION: CONDUCT THE FOLLOWING GAS TRAIN
LEAKAGE TESTS BEFORE START-UP, AT
ANNUAL INTERVALS AND PRIOR TO
INVESTIGATING THE CAUSE OF ANY REPORTED
OCCURENCES OF DELAYED IGNITION.
1. Using an appropriate bubble detection solution,
thoroughly coat all gas train pipe connections. If any
bubbles are detected, the leaking connection must be
tightened and tested to assure stoppage of the leak.
2. Attach a manometer. to measure gas pressure, at the
manual gas shutoff valve located just upstream of the
gas train. Adjust gas train inlet pressure to the
specified value (e.g. 14"W.C.), and tightly close the
gas train outlet manual shutoff valve.
3. Reattach the manometer to the gas train outlet
manual shutoff valve and record the measured gas
pressure in inches of water column (in W.C.).
Measure gas pressure again after 15 minutes. If gas
pressure has increased 00.5"W.C. or more, the gas
leak must be isolated to one or more of the operating
gas valves, for example a solenoid actuated gas
shutoff valve. After any leaking valve is replaced, the
reassembled gas train must be leak tested again
before start-up is attempted. (NOTE: All gas valves
removed because of suspected leakage must be
returned to PVI Customer Service for disposition.)
Spark Ignition Systems
These systems use 120 VAC power from an external
source and are equipped with transformers to reduce the
voltage to 24 volts to actuate the gas valve.
At start-up or during operation when the thermostat calls
for heat, the spark ignition system performs the following
basic steps:
1. Opens the flue damper.
2. Activates a high voltage transformer to supply a
sparking action to the pilot.
3. Opens the pilot gas valve. The pilot gas ignites from
the sparking.
4. A sensor located in the pilot flame signals the control
module to open the main burner gas valve. The pilot
flame ignites the main burner gas. An adequate pilot
flame must be present before the main burner gas
valve can open.
5. When the water temperature reaches the operating
thermostat setting, the control circuit opens which
closes both the pilot and main burner gas valves
terminating burner operation.
6. The flue damper is closed.
NOTE:
The spark ignition system provides additional
safety functions to close the pilot valve if the pilot
flame is not established and to close the main burner
valve if the pilot flame is extinguished while the
burner is in operation.
WATER HEATER START-UP
NOTE:
The following test equipment is required:
a. Vent temperature gauge
b. Manometer for checking gas pressure
c. Draft gauge for checking draft in vent
d. CO (carbon monoxide) tester
e. CO
2
(carbon dioxide) or O
2
(oxygen) tester
f. Drill and ¼" drill bit for ¼" hole drilled in vent
approximately 12" above draft hood outlet
NOTE:
Emergency shutoff can be made by turning off
the fuel inlet shutoff valve.
CAUTION: DO NOT START BURNER WITH
COMBUSTION CHAMBER FULL OF GAS OR WITH
VERY HOT COMBUSTION CHAMBER.
The following steps must be performed to assure
that the water heater is operating safely and
efficiently.
1. Read the enclosed control manufacturer's instruction
sheet for start-up procedure. Allowing the pilot to
ignite with the main burner gas valve turned to "off"
position is required at initial start-up. The pilot flame
can be visually checked for size and position. Check
inlet gas pressure. It must not exceed 14"W.C. Press
the control circuit switch on the front panel to "on"
position. The control system will open the pilot valve
allowing the pilot to ignite. Observe pilot flame. If
satisfactory, open the main burner valve and main
burner should ignite.
Pilot and main burner flames can be observed during
adjustment and under operating conditions by using
the stainless steel hand-held inspection mirror that is
enclosed in the information packet that was shipped
with this water heater.
If the spark ignition fails to ignite the pilot flame, refer
to the control manufacturer's manual supplied with
the unit.
2. Check gas pressure at the gas valve with a
manometer. (See Figure 2-5.) Most gas valves have
pressure taps for this purpose. Adjust gas pressure to
the value shown on rating plate of the water heater.
3. Drill ¼" diameter hole in vent about 12" above draft
diverter. Insert draft gauge in drilled ¼" hole. Draft in
vent should be -.02" -.06" W.C.
