Thread: Is this OK?

There are several things wrong with this installation. I am concerned about three water heaters connecting to one four inch single wall vent. One water heater, being used as a boiler, was 65,000 btu' and the other two were ~ 40,000 btu'. Is this acceptable or does the vent have to be larger.

Thanks

I'd be concerned that they are "T"d instead of having a Y into the pipe but the larger vent is pretty close.

Where's the shutoff valve and expansion tank for the leftmost heater?

Is that pex being used for the TPR line? (It *looks* like white pipe with a black crimp ring near the top, but I can't really see it)

What's supporting that vent near the 4" pipe?

I don't think you can lay that kind of vent flat like that.

If the left-most heater goes out, what keeps the middle heater from venting back down the left's pipe?

The expansion tank appears too small for the combined capacity of the three heaters. If one is on a separate closed loop system, it would need its own thermal expansion protection. But you probably already knew that and called it in your list of other problems.

Guys,
Thanks for all the imput. My question still remains, is that 4 inch vent large enough to handle all three heaters? The rest has been noted.

Thanks

The left most tank is used as the boiler for radiant heating system, it is separate from the other two. The valves are on the back side of the tank. The tpr lines are not PEX.

Based on Table G2428.2(1) [504.2(1)] the 4" is not large enough for the 145,000 BTU load.

Originally Posted by mathew stouffer

The left most tank is used as the boiler for radiant heating system, it is separate from the other two. The valves are on the back side of the tank. The tpr lines are not PEX.

Check this resource especially page 14.

As mentioned earlier, I see no expansion tank for heater being used for the radiant heat system.

Michael,
The expansion tank in on the floor behind the unit. No drip leg as well, like I said there were many issues with this installation

Originally Posted by mathew stouffer

Michael,
The expansion tank in on the floor behind the unit. No drip leg as well, like I said there were many issues with this installation

I noticed the missing drip legs but not all areas require them. They do in my area.

I hope that sizing chart was some help.

James,
Thanks for that ref. However, that table is for b vent. The four inch vent in the photo is single wall.

It's all I had handy....sorry! Single wall pipe would be less than the chart shows so my only opinion is that based on the chart 4" is not large enough for your load.

I found a 1980 NC Mechanical Code Book in the basement and Table 5 Appendix B says that you need a 7" single wall pipe for your total BTU load. You could go with a 6" if you have a 15' high vent or 5" if you have a 30' high vent. This is all single wall pipe.

Insufficient data provided. You need to size the common vent separately from the vent connectors. Here, I see a large B-vent all taped up with what appears to be a B-vent tee snout connector that then transitions to single walled vent connector. You use separate tables for the sizing of the connector and vent.

There is insufficient support of the connectors.
There appear to be 4" connectors on 3" draft hoods.
You can manifold multiple appliances but it must meet the code sizing and bottom line, it must work . Has anybody tested this installation? Do you have other issues such as makeup air? Any signs of spillage or condensation?

Sediment traps are ALWAYS required by code whether enforced or not.

Bob

Tape used on the flue pipes is the first giveaway that things are awry.

I went back to look at the radon machine and it is pex on the TPR line. This guy was having a bad day, plus it is a spec home. The PEX is rated for 100 psi at 160 degrees, the plumber said it is acceptable. Any thoughts.

Watts has a pex looking tpr drain tube made for the purpose. IF it was a purpose built tube from a manufacturer like Watts, I would not have a problem with it. If it is flexible pex, then there is a problem.

http://www.watts.com/pdf/ES-100DT.pdf

Pex is rated at 100psi at 160 degrees, but the TPR valve blows off at what, 180psi/210 degrees? If it's a straight shot down without making any bends where any pressure could form inside the pipe it probably wouldn't make much difference, BUT it's still not an approved material in the codebooks.

Thanks for all your imput and assistance, you have been very helpful. I am writing it up as further evaluation of the vent. The rest was written up as well. It is a spec home and they cut a lot of corners but it is still a 2 million dollar place, nice work huh.

I just read this about Pex:


PEX piping meets all requirements for pressure and temperature performance in residential applications. Consensus standards published by the American Society for Testing and Materials (ASTM) International specify temperature and pressure-resistant capabilities of PEX pipe and all tubing used in residential applications bears the appropriate test marking.
In the event of a water heating system malfunction, PEX piping is designed to accommodate short-term conditions of 48 hours at 210ºF (99ºC) and 150 psi (1034 kPa) until repairs can be made. The most commonly used safety relief valve (T&P) activates (opens) at either of these temperature or pressure conditions. All PEX piping has been tested to withstand T&P activation for 30 days to ensure that safety requirements are met. As such, PEX systems DO NOT require the use of a special T&P valve.

Mike,

That is not talking about the use of PEX as the T&P relief valve discharge pipe, that is talking about the PEX piping system being able to withstand those conditions for the stated 30 days.