Hi, I have a 22,000 gallon pool in Southern California. My current 175K BTU gas heater needs to be replaced. IF the gas line is too small (I don't know its size yet) and I install the large 400k BTU heater instead of the 250K BTU heater, will the heater adjust something if it does not get enough gas flow to it? If it doesn't adjust something will something bad happen like run lean and too hot? Thanks in advance.
Heater size selection
- Thread starter Paul6033
- Start date
- Jul 21, 2013
- 65,789
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Welcome to TFP.
The heater will not run properly if the gas service is undersized. The heater will run lean or may not run at all.
The heater will not run properly if the gas service is undersized. The heater will run lean or may not run at all.
If the line is too small, there are options. The normal regulator supplying your home (and the pool heater) supplies approximately 7" WC (water column) pressure (that is about 1/4 PSI). If the feed line to the house is typical - the gas company is sending higher pressure through their feed lines to the regulator at your house. You can have a different meter installed by the gas company that is a 2 PSI meter and have the appropriate regulators installed. One regulator to step down to 1/4 PSI for the house, run 2 PSI over to the pool heater and step down at the pool heater to the 1/4 PSI that it needs there. This was my original meter for the house, the original gas company supplied regulator is just to the left of the meter:
This is the replacement setup, the gas company supplied 2 PSI regulator is on the left of the higher therm rated meter, the 1/4 PSI regulator for the house is on the upper right where the pipe enters the house:
And at the pool heater where the 2 PSI feed is dropped to the 1/4 PSI for the heater (ignore the rubber gloves - plumbing still in progress) - the increase in PSI thru the pipe from the meter to the regulator at the heater allows smaller pipe to be used for that run:
-Tom
This is the replacement setup, the gas company supplied 2 PSI regulator is on the left of the higher therm rated meter, the 1/4 PSI regulator for the house is on the upper right where the pipe enters the house:
And at the pool heater where the 2 PSI feed is dropped to the 1/4 PSI for the heater (ignore the rubber gloves - plumbing still in progress) - the increase in PSI thru the pipe from the meter to the regulator at the heater allows smaller pipe to be used for that run:
-Tom
Tom,
The drip leg on the gas line pictured is incorrect. The "A" point should be in the bull nose of the T and the "B" should go to the heater and the "C" remains.
The drip leg on the gas line pictured is incorrect. The "A" point should be in the bull nose of the T and the "B" should go to the heater and the "C" remains.
@wireform can you show me a picture of how you think it should be? The colors don't make sense.
-Tom
-Tom
Your configuration is common but this one is better. The gas coming thru hits the dead end so the impurities fall to the drip leg and the gas goes up and across. Your gas valve is in the right place but the one pictured should of have it before the tee.
Gotcha - that picture makes sense. This was installed by a certified/licensed gas fitter - and approved by the local permitting department. If I ever have to open it up - I will consider making that change. Thanks!
-Tom
-Tom
Thanks everyone and thanks for letting me know about the option of a higher-pressure line. What flow rate do I need for a 400K BTU heater, and can I connect some sort of gauge at the heater end of the gas pipe to measure what I have?
Do you know what your gas meter is rated for? This was mine:
As you can see it is only rated for 275 CFH. A 400K heater needs (if I remember correctly) 400 CFH to function. So my gas meter was severely underrated for my usage - hence the replacement. Here is the replacement:
Here you can see it can supply 630 CFH and at 2 PSI it can supply much more.
So go look for the tag on your existing meter - it is likely too small for a 400K heater.
-Tom
As you can see it is only rated for 275 CFH. A 400K heater needs (if I remember correctly) 400 CFH to function. So my gas meter was severely underrated for my usage - hence the replacement. Here is the replacement:
Here you can see it can supply 630 CFH and at 2 PSI it can supply much more.
So go look for the tag on your existing meter - it is likely too small for a 400K heater.
-Tom