Did you check that the gas meter was maybe locked off ?
Use your manometer on the outlet (manifold) side of the gasvalve, you should have approx 3.5 in wc and between 3.2 to 3.8 in wc per the manufactors label.
If you have gas pressure thats good, but indicates an issue with ignition = ie: bad burners, crossovers, bug in orifice, air flow past ignitior gasket, and ect.
ps - stay around, maybe we can learn you a little bit.
most natural gas manifold pressures will be 3-3.5" wc
"wc is defined as the pressure exerted by a column of water of 1 inch in height
one pound pressure per square inch will lift a column of water 2.31 ft or 27.7"
inversley .433 psi will lift a column of water one foot. we usually round it off to 1/2.
most residential gas valves and regulators are rated at 1/2 lb pressure inlet max.
that would be about 14" wc
In North America, air and other industrial gasses are often measured in inches of water when at low pressure. This is in contrast to inches of mercury or psi for larger pressures. It is also used in natural gas distribution for measuring utilization pressure (U.P., i.e. the residential point of use) which is typically between 6 and 7 inches WC (6~7" WC) or about 0.25 psi.
.36 psi, or 27.7 in≈ 1 psi.
in my area most residential areas are around 7"wc. entering
hopefully you have a 1/4" plug entering the gas valve?
some gas valves have an 1/8" or 1/4" plug
I am old and always use an actual manometer.
I also use a digital testo to verify.
jp is right
you gotta start somewhere!
Originally Posted by robh1113
ok...gonna check my pressures tomorrow...I made sure gas valve was off until the correct diagnosis was made and fixed. I didnt want to jeopordize anyones life. Im here looking for help from experience techs and thankful for any positive help.
I WILL SELL WORK,GENERATE BUSINESS, GO GET NEW CUSTOMERS!
YOU SHUT THE HELL UP AND QUIT RUNNING YOUR MOUTH!
ok, I have a furnace that wouldn't come on for a customer. Its a Carrier natural gas hot surface ignition system. I came up to it and It went thru the initial cycle for heat, until the gas valve was energized. No gas outta valve. I got 24v to it, I checked the wiring, ground to furnace. everything looked fine. I had a universal valve on my truck and put it in. Same problem. Tomorrow im going back with my gas pressure test kit. I doubt its the new valve, but not impossible. What should my pressure in and out of the gas valve be? The furnace tag says min. 4.5" max 13.5" out...The pressure coming in should be what? I opened the shut off valve with the flex off and it seemed alittle week and was whistling as it was comng out. My guess is either the gas valve factory settings too low or the incoming pressure is weak...any suggestions...thanks
Wow ...... Really.......13.5" don't think so...... why on earth are you in someones home when you do not know the most basic thing.....I want to tell you but not allowed......better google it or ask your boss......
it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair