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Gas Regulator Minimum Distance From Appliance

RPK
RPK Member Posts: 119
edited May 2 in THE MAIN WALL

I am “involved” in a project that includes a gas-fired humidifier (Dristeem LX). The installation instructions state that the minimum distance between the regulator and inlet to the appliance is 5 feet. The regulator has been installed inches from the appliance inlet. The vendor has performed a “factory startup” and “approved” the installation. I’m looking for some real life examples of issues caused by this installation error. I recall having intermittent ignition issues with some Lochinvar Knights that ended up being related to regulators installed too close. Can anyone share similar experiences? I feel that I am justified in asking that the installer correct the error regardless of whether it was noted by the startup tech, but would prefer to also provide some potential risks associated with leaving it as is. Does anyone have anything to share? What is the theory behind this installation requirement?

Comments

  • Big Ed_4
    Big Ed_4 Member Posts: 3,036
    edited May 2

    Was the installation approved by the plumbing inspector?

    There was an error rendering this rich post.

    Mad Dog_2
  • Derheatmeister
    Derheatmeister Member Posts: 1,581

    Yes.. We had to repipe the gas supply/regulator to a Viessmann Vitodens boiler that another contractor had installed incorrectly.. It was constantly locking up and ruined multiple gasvalves prior to our Involvement

    Mad Dog_2ChrisJ
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,556

    Having some pipe after the reg probably gives the regulator better reaction time. Just guessing my own opinion.

    Most furnaces and boilers (residential) have the reg and gas valve built together in one control so that shoots my theory.

    Mad Dog_2ratioChrisJ
  • RPK
    RPK Member Posts: 119

    Big Ed, no plumbing inspector in this jurisdiction.

    Found an article that says if lockup regulator is installed very close and gas valve in the appliance closes quickly, the regulator may respond too slowly allowing pressure increase above the regulator setting and trapping high pressure gas between the reg and gas valve.

    https://controltrends.org/hvac-smart-building-controls/by-industry/commercial-hvac/burner-and-boiler/08/lock-up-gas-regulators/

    Mad Dog_2Derheatmeister
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,526

    No plumbing inspector? How about a "code enforcement" official..does all trades? That's common in small municipalities. Mad Dog

    Consulting by Mad Dog & Matt Jr.
    ChrisJ
  • ratio
    ratio Member Posts: 3,794

    I've seen issues where the regulator can't respond fast enough when the valve opens or closes.

    Another regulator issue that I come across is the regulator in the exhaust plume of the unit. It'll freeze up & stop flowing gas in cold weather.

    That said, if it works and the location isn't bad, I'd probably roll with it.

    ChrisJ
  • GGross
    GGross Member Posts: 1,317

    On some condensing boilers this will cause problems, I have no experience with a gas powered humidifier or how the gas valve works, I imagine it is similar thing though. You need a certain volume of gas on ignition for the flame sensor to correctly and reliably sense flame. I have had issues on a few mod/con boilers with this, usually it is someone thinking they are smart by running a reg right next to the unit so they can downsize their gas line so you get hit with a perfect combination of low gas volume on ignition. Intermittent flame failure was the symptom, it would sometimes happen several times in a row triggering a manual reset lockout of the control.

    ChrisJ
  • ChrisJ
    ChrisJ Member Posts: 16,308
    edited May 2

    Curious,

    If that's true and you were limited on room could you use a much larger pipe in between the regulator and appliance instead? For example if it calls for 5 feet of 3/4 could you do a foot of 2" instead.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

    Mad Dog_2
  • GGross
    GGross Member Posts: 1,317
    https://forum.heatinghelp.com/discussion/comment/1800829#Comment_1800829

    That was a solution given to me by a boiler manufacturer on one job, I don't remember the specifics of lengths and pipe sizes but they only had a foot or 2 to work with and moving the regulator would have been a pain

    ChrisJ
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,556

    It's also the reason some gas regulators have a separate sensing line piped from the reg piped several feet down stream. Not seen too often anymore, usually only in industrial applications.

    PC7060
  • RPK
    RPK Member Posts: 119

    Thanks to everyone for the replies.

    Regarding suggestions to reach out to code enforcement officials, without getting into too much detail, I am in the positions to more or less insist that the installation is corrected.

    I also reviewed installation literature for the regulator itself, which requires a minimum distance of “3 to 10 feet depending on the application.”

    EBEBRATT-Ed, I also found that this regulator can be ordered or retrofitted with an external control line, which is recommended if pipe size is increased by more than one pipe diameter at the regulator outlet.


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