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  1. #1
    Join Date
    Aug 2001
    Posts
    39
    I have a 40,000 BTU Heat-N-Glow fireplace insert that is currently connected to my natural gas via a 1/2 inch copper line. Even though the unit came with an adjustable flame height control I right now only have one flame height. A service man claimes this is because there is'nt enough pressure coming through the 1/2 inch copper line to use the adjustment control. I was advised to install 1/2 inch black pipe to increase the gas pressure. My city code also calls for ONLY black pipe because part of the run will be outdoors. So my question is will there be enough gas pressure if I use 1/2 inch black pipe or should I just put in 3/4 black pipe while I'm at it? I plan to tap into my indoor black pipe line at the end of a run inside my home and the whole run to the insert will be about 30 feet.

  2. #2
    Join Date
    Apr 2002
    Posts
    1,383
    1/2 inch black iron pipe should be ample, but then again, 1/2 inch copper tubing should be ample as well, if it was properly run and has not kinks and is not crushed.

    Did the service guy actually measure the pressure while the fireplace was operating at the fireplace and at the meter? If you have good gas pressure at the fireplace and have this problem, there's a problem at the fireplace. If the pressure is good at the meter and poor at the fireplace, the problem is with the fuel line. If the pressure is bad at the meter, you have a problem your utility needs to solve.


    Seattle Pioneer

  3. #3
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,049

    pressures?

    I basically agree with S/P. I would point out there is a big difference btw a static inlet pressure with just the pilot burning, again with the flame on, then again with the house under full load.
    I would never recommend gas lines under 1/2" under any circumstances. It used to be in the BOCA plumbing code. Have you ever seen a water heater or furnace with less than 1/2" line?

    Check with your AHJ about outdoor gas lines. Some allow CSST, some galvanized steel while others want black pipe painted.

    If your flame height is still not modulating properly after the gas line issue is resolved, contact HG Tech Support for the name of a qualified technician. Among the possibilities include bad valve regulator, debris in valve, blocked valve vent.

    HTH

  4. #4
    Join Date
    May 2005
    Location
    Madison, WI
    Posts
    1,078
    just curious if the service tech said what your inlet pressure was? normally it should be 5 or above to get the full range of flame height control. With a 30ft run you should definitely be able to pull over 40k BTU with 1/2" line. You also have to factor in the run length from where you tap in to the meter, this counts when sizing the 30ft section.

  5. #5
    Join Date
    Aug 2001
    Posts
    39
    I installed this insert myself an used an exhisting copper gas line that was formally used for a set of gas logs in which the flame adjustment worked fine but did'nt have the BTU output that the insert has. The insert is only six months old and still under warranty so if I change over to 1/2 inch black pipe and it still fails to work then I can have the flame adjustment control fixed at that time. I did check with my city and they want only black pipe. The service man never came to the house but informed me over the phone that he has seen other problems like mine that was fixed by switching over to 1/2 inch black pipe.

  6. #6
    Join Date
    Feb 2004
    Posts
    2,456

    you may want to ask your service tech if he checked for spider nest

  7. #7
    Join Date
    Apr 2003
    Location
    Northern Virginia, Fairfax County
    Posts
    641
    When the dealer's installer came by to give me options and estimates on the gas line run to my new Mendota fireplace insert, he said that one option would require replacing the line to the furnace with a larger one in order to maintain proper pressure to the furnace, water heater, and the insert.

    So even if the guys here are telling you that 1/2 inch iron can fix your problem, maybe you need to look at the length and size of the pipe from meter to furnace and water heater too. What are those dimensions? Is the pipe at the end of the run where you plan to tap in only 1/2 inch or 3/4 inch?

    By the way, the city wants iron now. Was the copper line accepted in code when it was installed? If so, maybe it is grandfathered now?

    Frankly, I would not make a move to replace the copper until doing what SeattlePioneer suggested, get a tech to measure the pressures in the system, with all other appliances running full load at the time. The pressure at the gas meter could be on the low side of standard. Without knowing the pressures, you are driving in the fog and just playing your hunches.
    Al

  8. #8
    Join Date
    Aug 2001
    Posts
    39
    I have a 3/4 inch as a main trunk line with 1/2 lines going to the furnace, gas clothes dryer and gas stove. The place I want to install the 1/2 line is the exact end of the trunk line which has a gas stove attached to it. I've been checking around and found a chart which shows natural gas CFH flow using different size pipes. It would appear to me that, if I'm reading the chart correctly, that using 1/2 black pipe would give about twice as much CFH than using 1/2(3/8ID) in copper tubing. Here's the chart:

    http://www.engineeringtoolbox.com/na...ng-18_826.html

  9. #9
    Join Date
    Aug 2001
    Posts
    39
    P.S. I also forgot to mention a 1/2 line going to the water heater.

  10. #10
    Join Date
    May 2005
    Location
    Madison, WI
    Posts
    1,078
    I would definatly have a HNG authorized tech come out and check the pressure before you go and replace the gas lines. Its under warranty so they probably would not want to charge you for it. It only takes a few minutes to test the inlet pressure. If you can get ahold of a manometer you could probably test it yourself.

    Also when you say "than using 1/2(3/8ID) in copper tubing" does that mean the copper is 1/2 on the outside and only 3/8 on the inside? I guess I never paid much attention to the inside diameter of blackpipe and CSST. Possibly if you are using only 3/8 line you are not getting enough pressure and putting in the black pipe would fix it.

  11. #11
    Join Date
    Aug 2001
    Posts
    39
    The copper is 1/2 inch(OD)and only 3/8 inch(ID) so even if I put in the black pipe I'll at least be bringing the install up to code and then if the insert flame control still fails to work I'll be able to have the manufacture fix the unit because the install would now be installed to the manufatures installation specs. The Tech stated he's seen this problem before and knows the problem is the units not getting enough gas pressure and that the 1/2 inch black pipe will fix it. Sooooooooo, I suppose I'll have to take his word for it and "Get Er Done", as the Cable Guy would say, and see what happens.

  12. #12
    Join Date
    May 2005
    Location
    Madison, WI
    Posts
    1,078
    The only thing is, he cannot "know" for a fact that its not getting enough gas unless he actually tested the pressure with a manometer. He is just making a good guess. If there are not faulty parts on the fireplace that is definitely the problem. It could also be that the regulator is bad which is not very common out of the box, in fact its not very common at all. So his guess is probably right.

    Have fun with the black pipe and I'd check out some sizing guidelines too, to make sure you dont take away too much gas from your other applicanes. Draw it all out and do the calculations.

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