1/2 or 3/8??

[leeklm]

Happy Friday!

Decided to go with gas hot water heater for my radiant heat, even with copper costing way too much... Kept trying to talk myself into electric since the install is so much more convenient, but NG should pay for itself with a few years.

I need to run about 150ft of Type K out to my shop in order to power a residential style hot water heater. Should I run 1/2" line, or is 3/8" sufficient for this?

Thanks!

 

[ishiboo]

Happy Friday!

Decided to go with gas hot water heater for my radiant heat, even with copper costing way too much... Kept trying to talk myself into electric since the install is so much more convenient, but NG should pay for itself with a few years.

I need to run about 150ft of Type K out to my shop in order to power a residential style hot water heater. Should I run 1/2" line, or is 3/8" sufficient for this?

Thanks!

Tank or tankless? How many total BTUs?

I would run at least 3/4" or 1". It's cheaper to dig the trench yourself and have a plumber come out and drop some PE (yellow plastic) pipe in, instead of doing the copper yourself.

 

[leeklm]

good point on the yellow plastic... heater is 50gal, 40K BTU. Are there typically different burial requirments on plastic pipe? Minimum here for copper is 6". Plan is to put my PVC/electrical at 18" and the gas around 8" in the same trench.

 

[Milton Shaw]

Check with your building code inspectors. Gas needs a lot of size in pipe for correct flow because its such a low pressure after the regulator. Every elbow, every fitting cuts that flow and requires a careful calculation to determine the correct size. If you are having another meter put in then the gas company runs full pressure to the meter with 1/2 " pipe. Otherwise it may take 1 1/2 to carry that load that far with bends in it.

 

[leeklm]

As I do a little more research on the topic, I see what you mean... Even if .75 inside diameter would do it, am looking at about $650 in copper.

 

[leeklm]

talking to a plumber, looks like I may be able to use 3/8 ID pipe. I have "high" pressure coming off my meter, with the house regulator in the basement. Should be able to run the smaller line, then a regulator in the garage... Will definitly keep the cost in check.

 

[Milton Shaw]

Good news on the high pressure off the meter. Normal gas line pressure from street is about 125 psi, from meter/regulator is 7" of water pressure. Then at each appliance another step down to 4" wp. It takes 33 feet of water pressure to equal 15psi, so its very low pressure after the regulator and takes a big pipe to go that far. I had a propane tank put in for a backup Genset and the line from tank to first regulator is just 1/4" copper since its high pressure, I thought it looked crazy but that's what the propane company ran for 3 feet before hooking to the regulator and the 1 1/2" I ran to the Genset.