39
LP- 428 REV. 9.2.14
D. CHECK INLET GAS PRESSURE
The gas valve is equipped with an inlet gas pressure tap that can be used to measure the gas pressure to the unit. To check gas
pressure, perform the steps listed below:
1. IMPORTANT! Before you connect to the inlet pressure, shut off the gas and electrical power to unit.
2. Loosen the pressure tap with a small screwdriver. Refer to Figs. 20 and 21 for locations.
3. Each unit is equipped with a needle valve that will accept a 5/16 ID hose to connect to a digital manometer or liquid gauge to
measure incoming pressure from 0-35” w.c.
4. Turn on the gas and power up the unit.
5. Put the unit into manual service mode (details on service mode are in the back of this manual). In service mode, monitor pressure to
assure it does not drop below 1 inch from its idle reading. If gas pressure is out of range, or pressure drop is excessive, contact the gas
utility, gas supplier, qualified installer, or service agency to determine the correct action needed to provide proper gas pressure to the
unit. If gas pressure is within normal range, proceed to Step 6.
6. Exit Service mode, then turn power off and shut off the gas supply at the manual gas valve before disconnecting the hose from the
gas monitoring device. Tighten the screw on the pressure tap, turn gas on, and check for leaks with a soapy solution. If a leak is
present, bubbles will appear on the pipe.
Ensure the pressure tap screw is properly tightened to prevent gas leaks. Failure to do so could cause substantial property damage,
severe personal injury, or death.
The gas piping must be sized for the proper flow and length of pipe to avoid pressure drop. The gas meter and regulator must be
properly sized for the total gas load. If you experience a pressure drop greater than 1" w.c. (.87 kPa), the meter, regulator or gas line
may be undersized or in need of service. You can attach a manometer to the incoming gas drip leg after removing the cap. The gas
pressure must remain between 3.5" (.87 kPa) and 14" (3.5 kPa) during stand-by (static) mode and while in operating (dynamic) mode.
If an in-line regulator is used, it must be a minimum of 10 feet from the boiler. It is very important that the gas line is properly
purged by the gas supplier or utility. Failure to properly purge the lines, or improper line sizing, will result in ignition failure.
This problem is especially noticeable in NEW LP installations and empty tank situations. This situation can also occur when a utility
company shuts off service to an area to provide maintenance to their lines. This gas valve must not be replaced with a conventional gas
valve under any circumstances.
DO NOT adjust or attempt to measure gas valve outlet pressure. The gas valve is factory-set for the correct outlet pressure and
requires no field adjustment. Attempts by the installer to adjust or measure the gas valve outlet pressure could result in damage to the
valve and cause substantial property damage, severe personal injury, or death.
To Next Page
Loading...
Need help?
General
