1

I have a small stove with a propane conversion kit and a 3gpm propane tankless water heater. This is for a small MIL suite ~650 sqft. Both the stove and the water heater are on the same exterior wall, about 6ft apart. The wall has no windows or other openings. I want to place 2 20lb BBQ tanks outside on that wall. I've been searching for information about connecting a changeover valve like used in RVs to them. From there, a short run of black pipe, through the wall to street elbows and a shut-off valve at each appliance. Both appliances have 1/2" connections. I can't seem to find specific information about connecting the tanks to the black pipe. What do I use? I am going to have this pressure tested and inspected after I'm done.

  • 40lbs of propane isn't a whole lot of propane, especially for a tankless heater! – ThreePhaseEel Sep 19 '16 at 0:23
  • I did the calculation on the tankless alone. 430k BTU tank and 75k BTU tankless (430000/75000/.25). A single tank should last about 23 days given a 15 minute shower once a day. I do not expect this to be used heavily. Some reviewers said they get between 45 and 60 days on a 20lb tank. The 75k BTU/hr is the max 45 degree rise at 3.4 GPM. A shower uses 2.5 GPM and we have between 62-72 degree water year round. – kyle Sep 19 '16 at 12:26
  • Ah -- good that you ran the numbers -- the duty cycle of your operation is what makes this different from the previous cases I've seen on this Stack. – ThreePhaseEel Sep 19 '16 at 23:11
  • After more than a year of running on BBQ tanks, I can say that this has worked out well. The propane powers both a stove and the tankless. Washing dishes, cooking, and showering is about a month per tank. – kyle Dec 12 '17 at 5:00
1

What I ended up getting was a hose with a regulator. On the other end was a 3/8" flare female. I found a 3/8" flare male to 1/2" MIP (Male iron pipe). I used a 1/2" coupling to a 3" nipple to a tee. From there it went to each of the 1/2" nipples through the wall, to a street elbow, and finally to a gas shutoff valve. This is the basic setup now. I'll have to order a changeover for the 2nd tank.

street elbow => shutoff         street elbow => shutoff
|              ---------        |
|                wall           |
|              ---------        |
|__________________Tee__________|
                    |
                    |
              1/2" coupling
                    |
        3/8" male flare to 1/2" MIP
Regulator with hose 5/8" female to 3/8" female
              propane tank

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.