Measuring & Adjusting Furnace Gas Pressure X2
ฝัง
- เผยแพร่เมื่อ 13 ก.ย. 2024
- Matt Milton and Robert Severson demonstrate the measuring & adjusting of furnace gas pressure using Fieldpiece and Testo manometers in the field. The processes in this video are to be carried out by trained professionals ONLY and are not described in full.
Matt Milton's tools include two Testo Smart Probes, tubing, two hose adapters (which come in a few different sizes), a service wrench, and an Allen wrench (3/16"). He begins his process by shutting off the gas line, making sure the valve is perpendicular to the pipe. While the gas is off, he removes his supply and manifold plugs, eventually replacing them with the hose adapters connected to the tubing and Smart Probes. He opens the gas valve and views his readings in the measureQuick app, which he compares to the values on the data plate. Matt needs to adjust his gas pressure with a screwdriver, and he turns the screw counter-clockwise to get the desired pressure.
With the gas pressure adjusted, Matt waits for the furnace to shut down and cool naturally. Once that's finished, he removes his testing materials and replaces the plugs.
Robert Severson measures gas pressure on a Carrier package unit. He starts off by checking the data plate and noting the rated gas pressure. He follows a similar process to Matt's where he shuts off the gas, locates the supply and manifold plugs on the gas valve, removes them, and replaces them with his testing materials. He prefers using a ratcheting service wrench over an Allen wrench, but both work fine for removing the plugs. Robert also uses a Fieldpiece manometer instead of Testo Smart Probes, which also works well and can test pressure switches.
Robert turns on his manometer, zeroes it out, and reads the gas pressure with the gas back on. He measures the gas pressure when the furnace is in low fire, and the gas pressure is slightly elevated. Slightly higher pressure is usually okay as long as it isn't more than 5% above the rated gas pressure. In high fire, however, the furnace kicks up significantly and needs its gas pressure adjusted.
Read all the tech tips, take the quizzes, and find our handy calculators at www.hvacrschoo...
Show this video to Testo so they make a version of the 510i where you can display both readings individually and the differential reading at the same time. Couldn't be that tough to have port 1, port 2, and differential displayed in the app.
Thanks once again Bryan as your videos are worth their weight in gold especially for up and coming techs!
Great video! At some point Jim Bergmann might comment on this and discuss clocking the meter and setting your high fire manifold pressure anywhere from 3.2-3.8”wc depending on orifice size, elevation, and combustion analysis readings 🤓 I’m sure he has a video on this somewhere.
I assume the input pressure is somewhat controlled by the utility and their pressure diaphragm at the meter so you would only want to reduce the input at valve if too high? My Rheem two stage furnace has a White Rogers valve which requires a 5/16 sleeve to cover the adjustment tube on the valve and which then connects to an adapter and hose to the manometer. It has a similar port for input measurement , but no means to adjust it ; further it’s not called for adjustment in the Furnace Manual. Thanks for the video!
Good stuff... Thank you, Sir!
ORB @ 5:58 ,The spirits in the ether are concerned with these gas adjustments..lol
Hi, awesome videos. For split system, where did 1.9 on first stage come from?
Screw In to INcrease. Works with most valves with a diaphragm and spring
You should of demonstrated the Carrier 3 stage furnace with throttle gas valve. I had to replace the valve and adjust the pressure for propane, that wasn’t enjoyable.
Never buy a carrier, are you not talking about a modulating furnace? Not 3 stages, modulating are garbage, all manufactures have had issues
Sr another great video thank for the tips
Thanks
It's a 0.125 thread, in case you'd rather spend $7 rather than a lot more because Yellow Jacket or Fieldpiece resells it to you.
I always put the cap back on and see what the pressure is. I’ve noticed gas pressure goes up a little bit when you put it on.
I enjoyed your video but what's the pressure for low Fire ? Plz reply
Who was the pipe dope master
What about the other type of gas valve that doesn't use the 3/8, it takes a much smaller hex which I think is 3/32 and you use a tube that goes over the manifold test port? I lost my hex bit and clicked on this video to see what exact size cuz I need to order another one
thanks sir
Good vid.
beginner question, but: what are the long term results if pressures are allowed to run too high? general overheating of the furnace/exhaust? and how about if the pressures run too low?
if it's over-fired you can get bad combustion (high co), premature hxt failure and overheating.
Good video but ........ in Matt's example he switched the 2 locations of the High/Low adjustment ports. At 5:30 he adjusts high pressure at the left port and at 6:19 he says the same left port is the low pressure adjustment port.
2ndly, the incoming gas pressure port is checked (label spec. calls for 7 iwc max - 5 iwc min) , yet no mention at all about high/low SUPPLY pressure after that. Not sure, but I think MQ app was showing supply pressure around 7.9 - 8.1 iwc if that's what line 810 is in the app. That is 1 iwc more than max spec of 7. Is that a problem. What is the solution?
3rdly, isn't the incoming supply pressure check dependent on all the other gas appliances usage. Like if a gas dryer, a instantaneous gas water heater, gas oven and a gas fireplace all were firing simultaneously, doesn't that pull down the supply pressure at the furnace inlet?
If supply is to high you turn down at the meters regulator. It is a good idea to check supply with other appliances running to make sure your gas line is sized right and doesn’t fall below minimum input. If supply is to high it can ruin your valve. The gas valves max and the furnace rating may not be the same but always go with what’s on the furnace tag
What would cause the outlet/manifold gas pressure change over time?
Service valve tool works perfect too
Edit that's what he was using too
Question What size torx driver was he using on the Goodman, with the Honeywell Gas Valve ? Thanks !!
what about lp
So you don’t perform combustion in conjunction with adjust gas pressure?
No.. combustion is for C02 output. All you need to measure is Temp Rise. W.C in each stage and observe the flame 🔥
1st. video doesn't show how to adjust INLET pressure to make sure it's right. How would you do that?
That depends. If it's a few inches high or low, call your gas company and have them adjust it at the meter. If it's 0 inches, pay your bill! Other than making sure your piping is skookum, there's nothing you should be doing to adjust input pressure.
Can’t you just install a regulator from the line coming in
How long did you wait before making adjustments.(I was told 15min) Ex if it’s 3.8 and I’m at 1.7 how long should I wait before adjusting?
Cause sometimes I adjust it and it barely goes up. I honestly be too scared to raise the pressure, scares it blow up on me 😅
The nameplate shows 10" WC for LP, that seems pretty high, I wonder what the flame color and CO is with that setting?
Sure need a conjunction combustion analysis
Ira alot easier than we think ... just have to not over think. study up and be confident w knowledge of what to do.
I’ve never worked on a furnace. Smh