Adding tee to water heater gas line drip leg

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gadolphus32

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My water heater has a drip leg on the gas line that looks basically like this (not my actual installation, just an image I grabbed quickly online):

hwh_pilot_valve.jpg


I'd like to tap into the gas line to install another appliance by removing the cap at the bottom of the drip leg, installing a tee and branching out from it. The bottom of the tee would be capped, and the middle of the tee would feed the new line.

Is there any reason I can't do this? I understand that the purpose of the drip leg is to catch debris and moisture at the lowest point in the system. It seems to me that the bottom of the tee would still serve this purpose in the configuration I propose, but maybe I'm missing something.
 

Terry

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Make sure your sizing is correct for both appliances.
Some places want the drip leg and other don't worry about it. You can tee off and add a second tee below. Assuming the sizing is right.
 

Jadnashua

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If the combined BTU needs of the existing WH and the new appliance exceed the capacity of the existing gas line, neither one will work right when both are calling for gas. They usually don't upsize branch runs to save costs, so adding on, may not be a viable option. Can't tell unless you know the effective length of the existing piping and the BTU needs of each.
 

gadolphus32

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Thanks all. The new line will feed a gas fireplace. The existing line is half-inch.

So I should calculate the total BTUs of the water heater and the fireplace combined, measure the length of the line and then use a chart like this one to figure out if the half-inch line will suffice?
 

Jadnashua

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Calculate what the line can deliver, then see if it is close. Each individually should work fine...they might not when both are firing full. It will make a (big) difference if you have higher gas pressure than 1/2#.
 

gadolphus32

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Thanks. I'll probably just stick with the 1/2-inch line. The fireplace is basically just for looks, not an everyday heat source. We plan to use it only occasionally and probably not at full blast, so I think it would be OK. I'll still do the calculations just to make sure it's not going to be severely under-supplied, though.
 
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