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Thread: gas regulators

  1. #1
    Join Date
    Jul 2010
    Location
    Denver, CO
    Posts
    435

    gas regulators

    I have had 2 experiences this week that have shown me how little I know and understand about regulators. My experience goes as follows, install and adjust. I have never looked much into the operation nor trouble shooting of regs.

    The first job I was on I was doing a typical PM on 2 120ton Intellipaks with 850MBTU furnaces. I found my outlet pressure was low (2.8 IWC) due to a low inlet pressure (5.5 IWC dynamic) when the min inlet required is 7 IWC. We have been doing the PM for years and never had a low inlet. So I suspect the regulator. It is a 2psi x 7 IWC reg that is maxed out. The only thing I found was that the 8 screws on the diaphram body were loose, which in my logic would mean that dirt and/or moisture could have entered the diaphram and caused a failure. Now I do not know if this is a justified diagnosis because of my lack of knowledge on regulators. What am I missing here or where is my logic wrong?

    The other job was a call that every gas appliance had stopped working in this warehouse. I get up to the first UH and it is trying to light the pilot but can't. I hear the gas pouring out of the pilot tube and know this isn't right. I put my manometer on the inlet of the gas valve and read 105 IWC. I didn't believe it so went to the next UH, then to the water heater, 105 IWC . I grabbed my magnohelic because that can't be right. I blows right past the 3 psi (84 IWC). I have to suspect that the gas meter regulator has failed. I did not see any signs of tampering or adjustment done. Its hard for me to believe this is how a regulator fails, I would assume a small pinhole in the diaphram or something alont those lines that would cause improper opreation but not complete failure to regulate. I should know more once Xcel gets out there and addresses it.

    Any knowledge and input would be appreciated and I could really use some good literature.

  2. #2
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361
    • If these regulators are at the meter, the utility is responsible.
    • 1st case is not piping based on history, but the gas pressure should be checked at the regulator to be certain. Debris from the high pressure side may be obstucting the small passagewas that direct pressure to control the pressure.
    • 2nd case must be a catastrophic diaphram failure.
    • Don't attempt repairs if they are not utility owned. Replace them.
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  3. #3
    If a regulator fails to keep pres down to set point,,,, REPLACE IT!!!

  4. #4
    I found a "REG" letting all 2 PSI to a RTU (1998 Carrier 250k input two stage) that would not let the valves (2) open, hence the " No Flame Sensed " Error!!

  5. #5
    Join Date
    Feb 2006
    Location
    Atlanta,GA.
    Posts
    875
    blocked vent port will cause problemsbecuase it is a very small orifice bugs like to make nest inside pipes in summer

  6. #6
    Join Date
    Jul 2010
    Location
    Denver, CO
    Posts
    435

  7. #7
    Join Date
    Aug 2008
    Posts
    91
    Check this link out if you haven't already. It also has links to other information. I use it often and iis usallylgood for a couple of days reading.
    Enjoy.

    http://en.wikipedia.org/wiki/Pressure_regulator

    This is also related and its pretty easy to understand.

    http://en.wikipedia.org/wiki/Bernoulli's_principle

  8. #8
    Join Date
    Jul 2010
    Location
    Denver, CO
    Posts
    435
    College has ruined me, I never venture to wikipedia. That is some good info Hardwater, and even better I will be checking out wikipedia more.

  9. #9
    Join Date
    Aug 2008
    Posts
    91
    Quote Originally Posted by HuNGRYTeCH View Post
    College has ruined me, I never venture to wikipedia. That is some good info Hardwater, and even better I will be checking out wikipedia more.
    Thanks! you will probably enjoy it.

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