Propane line size for tankless water heater

[mrtbolt64]

First time poster so be easy on me guys..

I am currently have a 32 x 48 garage be built. I am set to do radiant heat using a propane tankless water heater. I was looking at having a 500 gallon tank under ground. My question is. What size line is ran from the tank to garage?
In preparation, before the concrete is poured I can set a piece of PVC elbow into the concrete so the line can come inside.

I am clueless on this so any help would be appreciated. Our house is all electric and we do not have natural gas in our area. There was no way in hell I was going to heat this shop off electric. Thanks in advance

Chad Fisher
Medina Ohio

 

[Jackfre]

How far away is the tank from the building? I like to oversize gas lines myself. I'd run 1". You just don't know what you will be doing in the future and what your needs might be. The poly pipe is short money as well. Your LP supplier will handle the line from the tank to the shop.

Sorry to bring it up, but I suggest you re-consider your tankless for this application. There are small relatively inexpensive straight heat and combi boilers out there that have the feature set you want for a slick radiant system. Should you go with the tankless make sure it is with a manuf who supports them in that application.

 

[ducksface]

What does the manufacturer say to use?
That would be my first choice for information.

 

[Radiantec Guy]

Mrtbolt, as ducksface mentions, you really need to get this info from the manufacturer of the appliance you plan to use. If you can't find the info in the manual then give them a call and speak with the tech department. Many tankless heaters require at least a 3/4" line but the size is dependent on the distance and btu input of the heater.

Also, when the gas company does the install, be sure they have the unit specifications on site to make sure the installation is set up for the particular heater you are using.

Good luck with your project!

 

[CNGsaves]

One word . . . . . BIG.

List all the piece parts of your "tankless water heater radiant system" that you propose. Radiant gurus here on GJ will give advice on whether it will even work. I'll bet $2 that they say you should use proper LPG radiant boiler, and not a tankless water heater unit.

Be sure to list ALL details . . . .
a) distance from LPG tank to detached garage
b) Btu demand of the heater
c) pressure of LPG leaving the tank
d) other LPG demands on the 500 gal tank like house, etc.

Finally, your LPG line into building . . . MUST . . . come up from ground on OUTSIDE.
It has to enter building ABOVE GROUND so any underground leaks don't enter building.

LPG is heavier than air. It will pool where ever there is a leak.
You do NOT want that to happen inside the garage.

 

[csp]

The line from the tank to the garage will be under higher pressure than the line will be as it enters the garage. The regulator will be placed outside of the building, so the size of the underground line won't need to be as large as the appliance mfg. specifies for the supply line in the building.

Your propane supplier/installer should know what size line to run from the tank to the regulator.

 

[mrtbolt64]

Thanks for the replies. My plan is to have a 500lb tank buried behind the shop. I sent the local gas reseller a email with what I wanted and this is how they responded.

A 500 gallon underground tank is $1599. That does not include sales tax, propane or the following:

Install Fee: $89
Delivery Fee: $129
Regulators: $108
Blocks: $29
Fittings: $25
Debit/Credit Card Convenience Fee: $9.99

We use 1/2 Outside Diameter refrigerator copper tubing for our installs. We normally run sales on our tanks in the summer so you might want to keep your eye out for any deals we may have. Please let us know if you have any further questions.


Thank you,

Thrifty Propane
1-800-879-3152


I had contacted The Radianttec heating company and had them figure out a package. I already purchased the tubing and manifold from them but have yet to purchase the heater. They recommended an American 6.6 GPM Condensing Tankless, Indoor unit. They assumed I needed 49920 BTUs from their calc sheet and it stated that the heat provided by the floor would be 61440 BTUs. Sorry guys, but this is all greek to me. The garage is 32 x 48 with 12 foot ceilings and a attic truss to give me 18x48 up stairs that will be blocked off. The walls, ceilings, and floor will all be insulated.

I gave the wife the LoopCad program since she is an engineer and she figured out the routing for all the tubing which is going to be 6 zone system

The garage is being built now with concrete being done with in the next 5 weeks or so. I am just trying to pre plan any access hole I might want in the concrete ahead of time. Or threw the walls for that matter. CNGsaves, thanks for letting me know that it can not pass threw the concrete and it has to enter threw a wall.



Thanks for the help

 

[yeldogt]

Do yourself a favor -- call a couple of local propane companies. Family owned .. not a national one like Suburban. Ask them about an install .. Thrifty's estimates are horrible.

The line from the tank will be high pressure -- as my guy said ...... 3/4 will power anything you have. House: Huge stove/ WD/ Boiler. I would also price out a 1k tank .. not much more and gives you some flexibility -- any thought on a generator?

I would make sure any heater you buy is rated for heating not just "water heating" -- buy once.

 

[CNGsaves]

OP . . . you've got a GREAT looking shop !!

I'll "feather" my comment on making sure you have "Big" feeder line from your propane tank to garage. By big I'm saying to not settle for small pipe like 1/2" even if it's "high pressure" as you've pre-determined your maximum flow EVER that will reach the garage. . . . . . because there might be day in future that you abandon LPG (propane) and instead use NG (natural gas) if the GasCo installed pipelines in your area. You'd hate to abandon that and be forced to trench new line if you switched to NG.

Depending on distance, 3/4" would be better but I'd "Future Safe" and at least go 1" as it only costs minimal amounts to upsize when you're using plastic pipe.

Obviously, I'm big advocate of using yellow polyethylene plastic pipe with risers on each end that transition to black pipe steel above ground. Shutoffs are on each end so you can isolate the buried portion if needed. Plastic is forever solution instead of using copper tubing.

 

[csp]

because there might be day in future that you abandon LPG (propane) and instead use NG (natural gas) if the GasCo installed pipelines in your area. You'd hate to abandon that and be forced to trench new line if you switched to NG.

Unless his tank is in the exact same spot that a possible NG line would branch off of a main he's going to be trenching a new line anyhow.