How bad is a choke point in tankless WH gas line?

[Paulcmaine]

I am installing a 160,000BTU tankless unit in my home. My main gas line is 1" and the run to the water heater is about 10'. Unfortunately all the tee fittings on the trunk line are 1x1x1/2. There is a capped tee right by it and it would be very easy to tap in but replacing a tee is going to be quite a bit of work I would rather not do as I'm already tight on time. What is the likelihood I can get away with using the 1/2" tee? It is my own home so there's no real cost other than a small amount of wasted time if it doesn't work, unless I am likely to damage the water heater by underfeeding it.

 

[wwhitney]

If you have a short 1' section of 1/2" and then upsize until you get to the water heater (assuming you're not already there, your description of the lay out is not clear to me), then that 1' of 1/2" is probably equivalent to about 3' of 3/4" or 10' of 1". Just off the top of my head, those are approximate.

In other words, if you keep the 1/2" section very short, it's not insurmountable.

Cheers, Wayne

 

[Sponsor]

 

[Paulcmaine]

If you have a short 1' section of 1/2" and then upsize until you get to the water heater (assuming you're not already there, your description of the lay out is not clear to me), then that 1' of 1/2" is probably equivalent to about 3' of 3/4" or 10' of 1". Just off the top of my head, those are approximate.

In other words, if you keep the 1/2" section very short, it's not insurmountable.

Cheers, Wayne

Thanks Wayne, that makes sense and is what I was hoping. The layout is a 1" trunk line with an existing 1/2" reducing tee apprx 10' away from the WH that I'm trying to pipe in. I'll then come off of that tee with a 1/2 x 3/4 elbow to step it back up to 3/4" for the 10' run so it will only be the tee itself that is 1/2", everything else will be 1" and 3/4". Sounds like that should work.

 

[Jeff H Young]

10 ft to the meter thats all you need is 1/2 inch pipe . if you are talking about it being 10 ft from a 1 inch line and without mention of what is on the 1 inch line as far as a load in cfh or btu then that means nothing the line could be maxed out allready.
So without knowing any details I cant assume that the existing 1/2 inch tee is adequate for anything more than 35000 btu clothes dryer although its entirely posible it will work fine depending on the details