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Thread: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Question

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    Pentair Mastertemp 300 NaturalGas Heater / Gas Line Question

    Question for installers and those in the know:

    Pentair Mastertemp 300 natural gas being installed. Manual and front line Pentair tech support say 1" is no further than 50' and 1.25" is up to 200 feet. PB does not think this is correct and says my install at 100' is fine for 1". He is validating but I was looking for some insight on here.

    Appreciate any info.

    Thanks,

    Ted

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    This is my new high capacity meter if it helps:

    http://www.gmaci.com/AMCO%20Literature/SB%203520.2.pdf

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    Local code will dictate the minimum line size. Many local codes specify that the manufacturer's instructions should be followed. At any rate, the line should never be sized less than the local code or the manufacturer's instruction unless a qualified professional engineer designs the system.

    It really wouldn't make sense to put in a 1-inch line here.

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    A 1 inch line at 100 feet is fine. For that heater, you need no less than 3" WC, and no more than 10.5" WC at the inlet. Manifold pressure for natural gas should be right at 2" WC. If you have 10" at the meter, a 100 foot line would give you plenty of gas at the heater inlet. Any smaller, and you risk not having enough gas at the inlet to operate the heater correctly. You could go with 1.25" line, but its not really needed. I wouldnt use less than 1 inch line, though.

    It also depends on how much pressure is at the meter. If its higher than 10" WC, you can get by with a smaller line. It would be helpful to know what the pressure is coming out of your meter. If, for example, it 2 PSI, you can run 1/2" line, but a second regulator near the heater would be needed.
    14,000 gallon IG, Vinyl. Hayward 3/4 hp superpump, Penatair IC40 SWCG, Pentair automation, Hayward sand filter, Aqua Comfort heat pump, Hayward 400k Lo-Nox LP heater.

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    The heater requires a gas supply of not less than 4" (10.2 cm) water column and not more than 14" (35.6 cm) water column.

    The manifold pressure is set to -.2 (+/- 0.1) inches water column.

    The manual calls for a 1.25-inch gas line. If the heater does have any sort of problem, Pentair might void the warranty if the gas line does not meet its specifications.

    Also, as I noted above, the line has to meet local code, which usually specifies that the manufacturer's instructions be followed.

    http://www.pentairpool.com/pdfs/MasterTempOM.pdf

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    I know what the manual says
    As long as you get the proper pressure to the manifold, everythings fine. If you want to use 1.25" , do that then. It's no that much more expensive, but its over kill.


    Quote Originally Posted by JamesW

    The manifold pressure is set to -.2 (+/- 0.1) inches water column.
    This is a little misleading in the manual. What's referred to here is -0.2" below the reference pressure at the mixer inlet. You cant have a negative pressure at the manifold. The standard pressure for a NG heater of this size is right around 2" WC.



    (FWIW, i've held a gas fitters license for 20+ years)
    14,000 gallon IG, Vinyl. Hayward 3/4 hp superpump, Penatair IC40 SWCG, Pentair automation, Hayward sand filter, Aqua Comfort heat pump, Hayward 400k Lo-Nox LP heater.

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    Another thing to consider is that the distance being referred to in the charts is in equivalent feet of straight pipe.

    Even if the distance of the piping is exactly 100 feet, fittings such as 45s, 90s, valves etc. will increase the head loss and the corresponding equivalent length of the pipe.

    Therefore, a 100-foot distance from the meter to the heater could be significantly longer than 100 feet in terms of equivalent feet of straight pipe.

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    The attack would be to use plastic pipe with risers on either side. So no 45s or 90s, just slight gradual curves in a sweep like setup.

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    Quote Originally Posted by thadius65
    The attack would be to use plastic pipe with risers on either side. So no 45s or 90s, just slight gradual curves in a sweep like setup.
    Yep, that's how I'd do it. You can do the 1.25 inch if you like. Go ahead if its not that much more to do. If its really expensive you have a decision to make
    14,000 gallon IG, Vinyl. Hayward 3/4 hp superpump, Penatair IC40 SWCG, Pentair automation, Hayward sand filter, Aqua Comfort heat pump, Hayward 400k Lo-Nox LP heater.

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    Going with 1.25" PE. Not worth any risk when cost of product is so close. Ended up at $198 for a 125ft roll of PE. 1.25" risers @ $120 each plus trenching/labor.

    I guess my question is, should the risers be so much? and I just noticed a 1.25" Tee at $189. Are PE fittings that bad?

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    bk406,

    In addition to the pricing questions, is anyone other than the gas company allowed to use PE plastic pipe underground with risers, etc? Or is that a State to State thing?

    Thanks,

    Ted

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    Depends on the state. Talk to a plumber with a gas license he'll know.
    14,000 gallon IG, Vinyl. Hayward 3/4 hp superpump, Penatair IC40 SWCG, Pentair automation, Hayward sand filter, Aqua Comfort heat pump, Hayward 400k Lo-Nox LP heater.

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    Re: Pentair Mastertemp 300 NaturalGas Heater / Gas Line Ques

    Quote Originally Posted by thadius65
    Going with 1.25" PE. Not worth any risk when cost of product is so close. Ended up at $198 for a 125ft roll of PE. 1.25" risers @ $120 each plus trenching/labor.

    I guess my question is, should the risers be so much? and I just noticed a 1.25" Tee at $189. Are PE fittings that bad?
    Sounds about right. You might look around to find cheaper labor on trenching though. We had a couple of "handymen" types do the trenching for us and plumbers with PE experience to do the 125 foot 1.5" gas line for us. This really saved a bunch over the total cost. Make sure they put a locator wire on the PE though, as most cities will require this. PE is a bit more expensive, especially if it is "welded" because the equipment used is quite expensive and you have to be trained properly for install. You can't just go down to an HD or Lowes to find the proper pipe and fittings. You might be able to source this stuff at a place like Fergusons, but you still need specialized tools to hook it all up.
    38K in ground pool with attached spa. Current equipment: Easytouch 8 (521150) with IC-60 SWCG with web control by Autelis, 1x Pentair IntelliFlo 011018 pump (for filter), 1x Pentair 2HP WhisperFlo pump (for waterfall), 2X Pentair IntelliBrite 5G 12V lights, Pentair MiniMax400 NG Heater, Pentair SMBW2060 DE filter. Zodiac Barracuda MX8 cleaner on dedicated cleaner line. Lighting/home automation controlled by Insteon/ISY-99i.

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