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Thread: Converting LP heater to Natural Gas

  1. #1
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    Converting LP heater to Natural Gas

    How difficult is it to convert a Minimax 400 from LP to natural gas? We are switching the entire house over from lp to natural gas and cannot find anyone in Montgomery, Texas, area to discuss the pool heater conversion with. Thanks.
    17K gal 16X31 vinyl DE 3/4 HP Hayward Max Flo Ultra Vac

  2. #2
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    Re: New pool owner with questions

    In most cases, I think it can be done by simply replacing the orifice (your local gas dealer can explain) I think there might be some instances where the pressure regulator requires adjustment but I can't remember.

    We cook with LP and I ordered a new cookstove online that was set up for natural gas. To the best of my knowledge, I simply changed the orifices and it was all set for propane.
    Dave S.
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  3. #3
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    Re: Converting pool heater from lp to natural gas

    Conversion from LP to natural gas on any type of burner is a simple matter of changing out the jet that aeroselizes in the gas. LP vs natural gas are different sizes. Check with Pentair. It should be an easy change out.
    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: Converting pool heater from lp to natural gas

    Welcome to TFP to the both of you!!

    I've worked extensively with Max- E - Therm heaters and, with those, it's a simple change in the brass orifice in the in fluent line to convert from NG to LP

    No other change is required other than the orifice on the line coming into the 'block'
    Luv& Luk
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    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

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  5. #5
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    Re: Converting LP heater to Natural Gas

    Maxi therm, yes easy conversion.
    MINI MAX 400 no, all the orifices need to be changed and i believe (correct me if i'm wrong) the gas valve as well.
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    Re: Converting LP heater to Natural Gas

    I spoke to a Pentair rep. about this before and he said that you cannot switch from propane to natural with the older style heaters. According to him, the natural gas heater is a sealed combustion chamber and the propane heater is not. With the new Mastertemps and Max-e-therms it is as simple as changing out the orfices but not with the TSI's or NT's.

  7. #7
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    Re: Converting LP heater to Natural Gas

    The 400 plus or CH are not sealed. The 400 NT is.
    Bentwater listed his as just a 400, no NT designation.
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  8. #8
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    Re: Converting LP heater to Natural Gas

    Thanks for the various tips. I appreciate them all. Is there a designation in the model or serial number that identifies the type of 400 I have? Best guess is that the unit is 8 or 9 years old as it was installed during the constructon of the house. Appreciate the help. Like this site a lot.
    17K gal 16X31 vinyl DE 3/4 HP Hayward Max Flo Ultra Vac

  9. #9
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    Re: Converting LP heater to Natural Gas

    Does you unit have a fan that starts up prior to igniting? If so, you have a sealed chamber.

    Scott
    PoolGuyNJ
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  10. #10
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    Re: Converting LP heater to Natural Gas

    Scott: I do not believe it has a fan. I can see the tubes ignite when I take the front cover off and look up into the burner area. Beginning to wonder if maybe I should just buy a 20 gal lp tank and skip the conversion of this item from lp to natural. What do you think?
    17K gal 16X31 vinyl DE 3/4 HP Hayward Max Flo Ultra Vac

  11. #11
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    Re: Converting LP heater to Natural Gas

    You would know if you had a fan start before the heater fired. As such, what PoolClown said earlier is correct. The orifices for the burners and the gas block regulator would need to be changed. It is not something I reccommend a homeowner do.

    A 20 Lb tank isn't big enough. If it could be hooked up, it would last only a couple hours. How big is the existing tank(s)? My 300K unit burns several GPH. When the heater dies, then do the switch to an NG heater.

    Scott
    PoolGuyNJ
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  12. #12
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    Re: Converting LP heater to Natural Gas

    I spoke with Pentair and they confirmed that I will need to replace the gas valve as well as the burner tray to complete the conversion.
    17K gal 16X31 vinyl DE 3/4 HP Hayward Max Flo Ultra Vac

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    Re: Converting LP heater to Natural Gas

    HI, hope I'm not thread stealing here, but I have pretty much the same question about a pool heater. We set up our 33ft AGP this past fall and the only thing I didn't get finished was to plumb the gas to the heater. Our heater is also a propane heater, and I'd like to switch it over to Natural gas. It is the Hayward H200 series (200,000 btu's)

    If anyone could give me info on switching this from propane to natural gas, that would be great. I do understand a different orifice will be needed, but what about the valve? I know gas works on pressue, and propane is high pressure, while natural gas is low pressure.

    Any help would be great.

    Thanks
    Dan
    33' x 52" Swim and Play Inc. PARAGON AGP. Hayward H200 Heater. Hayward Power-Flo LX 1.5hp pump. Sta-Rite Cristal Flo T-210WF Sand Filter. Stenner 45M5 chlorine pump

  14. #14
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    Re: Converting LP heater to Natural Gas

    Same deal. Sorry.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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