Originally Posted By: psmothers
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Anything in IRC about 2 water heaters useing the same TPR drain line?
Anything in IRC about 2 water heaters useing the same TPR drain line?
Originally Posted By: rmoore
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IRC P2803.6.1 Requirements of discharge pipe. The outlet of a pressure relief valve, temperature relief valve or combina-tion thereof, shall not be directly connected to the drainage system. The discharge from the relief valve shall be piped full size separately to the floor, to the outside of the building or to an indirect waste receptor located inside the building. In areas subject to freezing, the relief valve shall discharge through an air gap into an indirect waste receptor located within a heated space, or by other approved means. The dis-charge shall be installed in a manner that does not cause per-sonal injury or property damage and that is readily observable by the building occupants. The discharge from a relief valve shall not be trapped. The diameter of the dis-charge piping shall not be less than the diameter of the relief valve outlet. The discharge pipe shall be installed so as to drain by gravity flow and shall terminate atmospherically not more than 6 inches (152 mm) above the floor. The outlet end of the discharge pipe shall not be threaded and such dis-charge pipe shall not have a valve installed.
(my bold)
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Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
Originally Posted By: dvalley
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Why would any one waste their time improvising this type of set-up anyways?
It's much easier installing two separate pipes.
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David Valley
MAB Member
Massachusetts Certified Home Inspections
http://www.masscertified.com
"Some cause happiness wherever they go; others, whenever they go."
Originally Posted By: Jay Moge
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not to mention that if you connect two half inch pipes you creat one inch of flow, right? so to make the whole thing more complex and not worth the effort because all you did was make twice as much work and reduced the size of the flow neede. the best and easiest way would have been the right way,…weird how that works sometimes.
Originally Posted By: rmoore
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| Jay Moge wrote: |
| not to mention that if you connect two half inch pipes you creat one inch of flow, right? |
Ummm...and Huh????
Jay...I'm not sure I understand that last post. No...I lie...I'm sure I don't. 
But, just for clarification even if it does seem somewaht unrelated to the photo, the cross section of a 1/2" pipe is apprx 0.196 sq". That of a 1" pipe is 0.785 sq" (again apprx). It takes four 1/2" pipes to equal the flow capacity of a single 1" pipe.
Yeah...I know I need a life!
Originally Posted By: mthomas2
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OK. But I gotta? ask: is this really a significant defect? The discharge pipe is separate from other plumbing, and the only way I can the see ?reduced cross section issue? being a problem is if both TPRVs are simultaneously active ? a building fire, perhaps?
Originally Posted By: mthomas2
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Hum… and I guess you could argue that it makes it more difficult to identify which TPRV is dripping… that woud go part of the distance toward making it “significantly deficient”.
Originally Posted By: psmothers
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Thanks! Did anyone catch that they were installed in series and not parallel?? I know its a little hard to see in that picture…
Originally Posted By: rcooke
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| psmothers wrote: |
| Thanks! Did anyone catch that they were installed in series and not parallel?? I know its a little hard to see in that picture.... |
Good one You are correct.
I brightened the picture up and it showed well thanks . Roy sr.
Originally Posted By: rmoore
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For anyone interested…here’s a couple of good links explaining parallel versus series.
http://www.hotwater.com/bulletin/BULLETIN%2064.pdf
http://www.rheem.com/includes/resourceLibraryPDF/1231.pdf
The Rheem site seems to suggest that if the water heaters are not equal size then series may be better. Same size, then parallel is the way to go. Note that parallel piping should be equal or "balanced" up to the connection point.
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Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
Originally Posted By: psmothers
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Good links. I did not write up the in series issue. I have seen and heard many sides to that story that I just leave it alone now. Does anyone note the in series water heaters???
Originally Posted By: rmoore
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| psmothers wrote: |
| Does anyone note the in series water heaters??? |
I've never had to "cross that bridge" yet. The homes I've done with two water heaters have all had them on separate floors. Tough to say whether that would be considered series or parallel. I agree that there does seem to be varying opinions. I think if I ever see a set up like your photo, I wouldn't actually call for repair but will probably do a "commentary", including the links from above, and leave it at that.
--
Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
Originally Posted By: Jay Moge
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| rmoore wrote: | ||
Ummm...and Huh???? Jay...I'm not sure I understand that last post. No...I lie...I'm sure I don't.  But, just for clarification even if it does seem somewaht unrelated to the photo, the cross section of a 1/2" pipe is apprx 0.196 sq". That of a 1" pipe is 0.785 sq" (again apprx). It takes four 1/2" pipes to equal the flow capacity of a single 1" pipe. Yeah...I know I need a life! |
i tried to say it as best i could, but i got a little brain cramp myself. what i mean is, if the pipe on one needs to be half inch, and the other half inch as well, then assume that the worst case senario happens and both t.p.r.s' pop at the same time, so now we have 2 half inch pipes discharging into one half inch pipe, wouldn't that be the same as a single t.p.r. with a down pipe reducing in size. oh my brain hurts, i hope that made sence. 
Originally Posted By: dvalley
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This combination is not likely in Mass. I’ve only seen a few situations where two w/h’s were connected to each other. Most in our area either separate them or utilize a bigger wh’s.
The wh's I do find that are piped to each other were all piped in parallel.
If I were to find them piped in series, I'd inform my client how they operate. Let them decide.
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David Valley
MAB Member
Massachusetts Certified Home Inspections
http://www.masscertified.com
"Some cause happiness wherever they go; others, whenever they go."
Originally Posted By: sobrien
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Hello all.
What temperature is the discharge pipe rated for? (and what type of pipe is it?) In my area many water heaters were installed using pollybutylene pipe which is not rated for the temperature released from the TPR. Some new plastic pipe has made it up here that is specifically designed for this application, but Its seems to be quite rare still.
Sean 
Originally Posted By: psmothers
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This pipe was CPVC. I do see my fair share of them done in regular PVC here but have yet to run into any done in poly or pex.