Water heaterTP valve piping, what to do??

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BurleyMike

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Hopefully this spring I will finally be finishing the basement. I did a radon test and will need a mitigation system. Currently the water heater TP valve plumbing goes into the sump pump basin. Since it will have to be sealed for the radon system what are my options. Is it possible to have it go into a condensate pump? I would also like to put a pan under the water heater just in case it ever leaks.
 

Tom Sawyer

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Run the TP drain into the pan and the pan drain into an air gaped trap that dumps into the sump pit.
 

hj

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If the T&P valve EVER discharges it will overflow a condensate pump OR a drain pan in a matter of seconds. Sometimes I think getting a Radon test is like going to the optometrist. With the first you seem to ALWAYS need remediation, and with the latter you always walk out with glasses.
 

Mliu

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Since a T&P valve discharges under pressure, is there a requirement for the discharge pipe to gravity-drain? In other words, can the discharge outlet be installed above the level of the T&P valve? If so, the OP could plumb the line out of the basement.
 

Bluebinky

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Since a T&P valve discharges under pressure, is there a requirement for the discharge pipe to gravity-drain? In other words, can the discharge outlet be installed above the level of the T&P valve? If so, the OP could plumb the line out of the basement.
As far as I know, the drain needs to go down, not up.

I've read that there is a way to use a temperature-based energy source cutoff (watts valve??) and a pressure release higher up in the system.

Someone with actual experience with such a setup (probably hj or Terry) can explain much better...
 

Terry

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A T&P valve can not be plugged, or grade upwards.
It's a full bore gravity drain.

In cases where you can't drain a water heater T&P, we install a 125 PSI on the incoming cold at a high enough elevation so that it can be drained.
We also install the standard 150 PSI/210 degree T&P on the water heater. In this arrangement, it's unlikely that the water heaters T&P would ever leak. Still, it's not a bad idea to have a pan under the relief line in case it drips some.
 

hj

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quote; In this arrangement, it's unlikely that the water heaters T&P would ever leak.

Only if you also assume the thermostat will never fail and cause the Temperature side of the valve to discharge. If that happens it will flow until the temperature drops to a safe level which could be several, or more, minutes.
 

Terry

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The entire city of Bellevue was plumbed this way for years.
I didn't like it, but it was how the inspector wanted it.

Certainly better then running a gravity drain up hill though.
 

Hackney plumbing

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I built a homemade water cut off device out of a 12v solenoid valve and a float switch that you see wired into HVAC systems. I installed it at the top of the pan that didn't have a drain. It had to have 12v of power to shut the water off. If the power was off it would still allow flow. This is called a normally open solenoid.

Sure it didn't meet any code but it worked for my purpose. Just a project. I still have it and would use it again if the need came up. Its a Parker solenoid.
 

BurleyMike

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Thanks for all the ideas. I am going to insulate the walls with foam so I have to sheetrock them to meet fire code. Any amount of water could be very damaging so a K.I.S.S. solution is preferable. I really like the idea of using a 125PSI valve on the cold side though it would not prevent a leaking tank or failed thermostat. I think I will run a floor drain into the sump and put a trap primer on it. That will take care of the A/C condensate line as well. Previously it drained into the open sump pit. I was concerned about routing that outside with all the critters that could plug the pipe.

I don't know how big a deal radon really is, I grew up in an older house in a really high radon area. Perhaps it will get me someday but who really knows. My daughter will be sleeping down there so I don't feel comfortable not doing something to lower the level. Now to rent my favorite tool again, the Bosch Brute.
 
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Thanks for all the ideas. I am going to insulate the walls with foam so I have to sheetrock them to meet fire code. Any amount of water could be very damaging so a K.I.S.S. solution is preferable. I really like the idea of using a 125PSI valve on the cold side though it would not prevent a leaking tank or failed thermostat. I think I will run a floor drain into the sump and put a trap primer on it. That will take care of the A/C condensate line as well. Previously it drained into the open sump pit. I was concerned about routing that outside with all the critters that could plug the pipe.

Any way to run a floor drain out instead? Fortunately our walk out basement (where the WH is) already has this since we have other plumbing on the level. I tend to not trust sump pumps because they require power to work and you probably won't know they have died until something floods. When I was house hunting I did so on rainy days and listened for the sound of the pumps kicking on. Those that needed the sump pump to stay dry were scratched from my list.

I don't know how big a deal radon really is, I grew up in an older house in a really high radon area. Perhaps it will get me someday but who really knows. My daughter will be sleeping down there so I don't feel comfortable not doing something to lower the level.

Same issue with my daughter here. There is strong evidence of the link with radon gas exposure in miners, so when our numbers came in high before purchase I required a mitigation system before I would close. The radon risk is all about probabilities. Our area is one of those where about 50% of the homes test on the high side.

From what I've read the radon risk can be largely controlled passively by proper design. A vent stack (or stacks) can be put in place during the build, but not connected to a vacuum device. Generally just having the stack along with proper site prep provides a pathway for the radon gas so that it doesn't enter the home. If the home tests high, then the vacuum blower can be installed.
 
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Forgot to add: you might want to consider using something other than standard sheetrock in that area. I used greenboard in my utility space when I replaced the HVAC because of condensate drain and other issues that had led to some wetness in the past. I threw these up myself (along with insulation) during the HVAC replacement since the old sheetrock was a wreck or incomplete behind the unit. I had proper condensate drain routing done during the HVAC install, and I had previously insulated some ductwork that I discovered would drip from above into the studwall cavity, so I doubt I'll ever have the issues again.
 
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