Pool Heater Gas Line

[Phillyk610]

Hey guys! I found this forum searching for answers to my question. I can’t find anything so hopefully someone here can help me. I am not a plumber but used to do a lot of outside work running rigid and pvc pipe when I was in the electrical union and do most of the work at my house.

I just got a pool heater basically free and would like to get it hooked up asap. It is a natural gas heater and I bought the propane orifice to convert it.

Long story short, my neighborhood just got natural gas lines installed. To run a line to my house they said it would cost $2100. I can’t afford that right now but plan on doing it in the next year or two. I currently have a 120 gallon propane tank that just feeds my fireplace insert. I know this is far below the size I should have to run a pool heater. It is only a temporary solution until I get gas ran to the house and will only use it on colder days.

My pool heater (400k btu) is around 125ft to the propane tank and the gas meter will eventually be in that same area. From my understanding I would need a 1 1/2” pipe to run natural gas. I know propane doesn’t have to run through as wide a pipe. Pentairs website says 1 1/4 for propane, which still seems big but whatever.

My question is: can I run propane through the 1 1/2 pipe temporarily without issues until I get natural gas hooked up? I know another solution is to run a separate pipe for each but am hoping to avoid this.

Once I run the pipe I plan on having a buddy help me with the final hookups and pressure testing.

Thanks for your help everyone!

- Phil

 

[JG plumbing]

I would run an inert gas perge between switching fuels and call it a day. Get you a nitrogen bottle and run it dry.

I'm sure someone is going to tell you that this isn't needed, but it's what I'd do. Keep in mind I'm not a chemist. Just a plumber.

 

[Phillyk610]

Thanks I’ll look into that. Do you think running 1 1/2” pipe will work for propane?

 

[Twowaxhack]

Have your gas guy set you up a high pressure regulator for a dedicated line to the pool heater. You may already have this and just need a tee in the line.

This will be set at a higher pressure allowing you to use a smaller pipe and then you reduce the pressure again at the pool heater.

Higher the pressure the smaller the line can be, then reduce pressure at the equipment.


I do this with natural gas all the time.

I actually did it today, I used 3/8 copper 25’ to a natural gas grill......2lb on the 3/8” line then I reduce pressure from 2lb to 8” water column with a pressure regulator at the grills inlet.

 

[JG plumbing]

Yes. You'll just have to adapt it to fit the inlet on the heater. That seems like pretty big pipe. Not sure you need that even.

What kind of pipe are you running? Regular malleable iron pipe?

 

[Twowaxhack]

Delivery pressure means everything.

Lower the pressure the bigger the pipe must be.

To size the line you must know the delivery pressure available. The rest you have told us.

If you’re eventually going to use natural gas then you’ll need to contact your gas supplier and ask what pressures are available in your area.

Hopefully they offer 2lb systems or higher pressure....

 

[Mitchell-DIY-Guy]

Did anyone tell you that you were going to go broke heating a pool with a propane heater? Or that your propane delivery guy is going to become your best friend because he’s going to be coming all the time? A 400,000 BTU/Hr heater uses a tremendous amount of gas. The typical fireplace may use about 30,000 BTU/Hr.

All these calculations with gas pressures, pipe sizing, and what have you are great, (particularly for planning for the future) but there are some other calculations I would do.

What is the gas consumption per hour on the heater? How many thousand gallons of water does your pool have? This is not like a furnace that you just turn it on and be warm in a few minutes.

My rough guess is you’ll use 4 gallons of propane per hour. Thus a full tank will allow just 30 hours of use.

Here's some information to ponder...

https://www.poolsupplyunlimited.com/how-long-will-it-take-to-heat-my-pool/blog/100

 

[Phillyk610]

Yes. You'll just have to adapt it to fit the inlet on the heater. That seems like pretty big pipe. Not sure you need that even.

What kind of pipe are you running? Regular malleable iron pipe?

Thanks. I plan on using the IPS polyethyline pipe. According to the chart I have I would need 1 1/2” to run natural gas 125-150’ away.

 

[Phillyk610]

Did anyone tell you that you were going to go broke heating a pool with a propane heater? Or that your propane delivery guy is going to become your best friend because he’s going to be coming all the time? A 400,000 BTU/Hr heater uses a tremendous amount of gas. The typical fireplace may use about 30,000 BTU/Hr.

All these calculations with gas pressures, pipe sizing, and what have you are great, (particularly for planning for the future) but there are some other calculations I would do.

What is the gas consumption per hour on the heater? How many thousand gallons of water does your pool have? This is not like a furnace that you just turn it on and be warm in a few minutes.

My rough guess is you’ll use 4 gallons of propane per hour. Thus a full tank will allow just 30 hours of use.

Here's some information to ponder...

https://www.poolsupplyunlimited.com/how-long-will-it-take-to-heat-my-pool/blog/100

Thanks. I already did account for that and you’re right it will be around 30hrs of use. I know it will cost a lot to run but I only plan on heating it up when we have get togethers on colder days. My pool is in the sun all day stays fairly warm. Plus I use a pool cover at night to help w heat loss and evaporation. Thanks for the reply.

 

[Phillyk610]

Delivery pressure means everything.

Lower the pressure the bigger the pipe must be.

To size the line you must know the delivery pressure available. The rest you have told us.

If you’re eventually going to use natural gas then you’ll need to contact your gas supplier and ask what pressures are available in your area.

Hopefully they offer 2lb systems or higher pressure....

Thanks for the reply. So if I understand correctly, my next step should be to see how much pressure my 120gal propane tank outputs currently. And if I want to use the larger gas pipe for propane then the pressure should be lowered to account for this (if its not already).

 

[Phillyk610]

Have your gas guy set you up a high pressure regulator for a dedicated line to the pool heater. You may already have this and just need a tee in the line.

This will be set at a higher pressure allowing you to use a smaller pipe and then you reduce the pressure again at the pool heater.

Higher the pressure the smaller the line can be, then reduce pressure at the equipment.


I do this with natural gas all the time.

I actually did it today, I used 3/8 copper 25’ to a natural gas grill......2lb on the 3/8” line then I reduce pressure from 2lb to 8” water column with a pressure regulator at the grills inlet.

Thanks for the reply. So are you saying that I could use a smaller pipe than 1 1/2” and when I eventually get NA gas hooked up I would have to raise the pressure from the meter?

 

[Twowaxhack]

I would size the pipe according to how much pressure the natural gas supplier could set me up for.

It’s either going to be low pressure 8” water column or 2lb or 5lb.

We have a choice of low pressure 8” wc or 2lb.

I wouldn’t connect a pool heater to a 400 gal propane tank.

The higher the pressure the smaller pipe can be used.

 

[Mitchell-DIY-Guy]

Thanks. I already did account for that and you’re right it will be around 30hrs of use. I know it will cost a lot to run but I only plan on heating it up when we have get togethers on colder days. My pool is in the sun all day stays fairly warm. Plus I use a pool cover at night to help w heat loss and evaporation. Thanks for the reply.

Perhaps one of those cheap solar heaters would be a better solution...

 

[Twowaxhack]

It takes a whole day to raise the temp just a few degrees in a typical swimming pool.

 

[havasu]

I have a small, 10,000 gallon (small pool) spool. I purchased the 400k BTU NG heater, and my temp climbs about 4 degrees an hour. Very economical, but it costs about $30 a day to use.

 

[Twowaxhack]

I have a small, 10,000 gallon (small pool) spool. I purchased the 400k BTU NG heater, and my temp climbs about 4 degrees an hour. Very economical, but it costs about $30 a day to use.

I just checked and the two pools I was thinking about.......one is 40k gallons and the other one is 26k gal.

It seems the typical pool around here is huge. My mistake for sure.

The 40k pool takes a good 24 hrs to warm up from 55-60 degrees with this 500k small commercial heater. I know this because my kids swim in it.

 

[Mitchell-DIY-Guy]

Not a whole lot different than my de-icing system...trying to get 26 tons of concrete (my driveway) to 32 degrees plus a smidge. Took 6 hours to get some action...
But those days are gone...