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Gas line size for 250k btu natural gas pool heater

Snyder9erSnyder9er Member Posts: 2
Here is my current situation:
We built a new pool last fall and the heater recommended for that size pool was 250k btu's, so that is what we bought. We probably should have investigated installation better prior to purchase, but that ship has sailed.
We have a 500k gas meter per the gas company.
The gas meter is located at the back of the rear neighbor's property (long story). So it is 300-400 feet away from my house.
We have a 40k water heater, a 80k furnace in the house, a 125k hanging furnace in the shop and now this pool heater (all appliances less than 5 years old). The gas company says we are fine for the meter. I'm assuming because the likelihood of the pool heater and both furnaces all running at the same time is very slim. Is that correct?
Secondly, the gas line to the house from the remote meter is 1". There is already a tap in the basement of our house, 50-60 ft away from where the pool heater will go. It is 3/4" in the basement. The pool heater instructions say it needs 1.5" line to the heater. Is that right? What is the downfall of having a 3/4" line from the basement to the pool heater? Any other suggestions?


  • JUGHNEJUGHNE Member Posts: 6,788
    What pressure comes from the meter to your house?
  • ZmanZman Member Posts: 5,735
    A drawing would help as would a picture of the regulator at the meter. If you have 2# gas, you can probably make this work.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    delta T
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,930

    Unfortunatley it will not work. A 1" line is way too small for the pool heater. In fact a 1" line is undersized for the equipment you have installed without the pool heater.

    The question is who owns the gas line between the meter and your house? If you own it it's a problem.

    Why is the meter so far from your house? Your looking at a minimum 1 1/2" line maybe 2".

    Maybe you could get the gas co to run the new gas line and relocate the meter to your house. I have never seen a building with the gas meter 3-400 feet away
  • ratioratio Member Posts: 2,331
    With undersized gas lines, the gas pressure will sag when the unit fires. While this sag can sometimes be accounted for when the combustion is dialed in (using a digital combustion analyzer), it's hard to do that when other appliances fire off more-or-less randomly. If the sag is great enough, the appliance won't fire at all, or can burn improperly -> a dangerous condition.

    TL;DR: You need to run a new gas line. Carefully size the gas line per any of the old gas line sizing tables & you won't be disappointed.

  • Mike_SheppardMike_Sheppard Member Posts: 657
    We need to know what the pressure coming from the meter into your house is. If it is less than 2 psi (which I am sure it is) then 1 inch at 300 feet is not even large enough for your furnace and water heater alone.
    Never stop learning.
  • ZmanZman Member Posts: 5,735
    2 psi gas for this kind of application is very common in my area. I would be surprised if the OP does not have 2 psi, nothing would be working without it...
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    delta T
  • HVACNUTHVACNUT Member Posts: 3,266
    Clock the meter running each appliance separately.
    Clock the meter with all appliances on.
    I think you'll find upgrades need to be done.
  • pecmsgpecmsg Member Posts: 1,388
    I highly doubt the original install increased the line size almost double in anticipation of a pool heater!
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,930
    Exactly. I always install a gas line 2 pipe sizes larger than I need. You get more jobs that way. Not. Especially pool heaters which by themselves are usually more load than all the other appliances added together.
  • delta Tdelta T Member Posts: 809
    Is there a gas regulator where the gas line enters your house?
  • Tim McElwainTim McElwain Member Posts: 4,357
    You need to find out what gas pressure you have coming out of the meter. Give me that and I can tell you what you need.
  • ZmanZman Member Posts: 5,735
    @Snyder9er One and done?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Snyder9erSnyder9er Member Posts: 2
    The gas company said “7 inches water column, 0.2 psi”.

    They’re coming out tomorrow to see if it can be turned up to “10 inches water column, 2psi”

    But they’re telling me we will have to put a regulator on the line to the house furnace/water heater and then another on the line to the shop furnace.
  • ZmanZman Member Posts: 5,735
    2 psi is about 52" wc
    Yes, you will need regulators to step it down.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Tim McElwainTim McElwain Member Posts: 4,357
    An other alternative is put the pool heater on Propane and put the Propane tank near the heater.
  • mikeg2015mikeg2015 Member Posts: 1,178
    With that distance, yes, you will need a 2lb line run to the pool heater, then a seperate regulator. A good HVAC company can handle this and startup the pool heater. A lot of homes near us in IL have 2lb systems and regulators at the equipment.

    Might need to start with the gas company. May need a different meter and chance to current setup.
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