View Full Version : Check vavle on domestic side of hot water heater.
We had a boiler guy (not on this forum) out a couple months ago and since then the TP valve has been blowing off pretty regularly. I know very little about water systems but from the research I've been doing I think he caused an issue by installing a check valve about 3' in front of the water heater on the cold water input line from the well. There is no expansion tank on the hot water system.
We plan to have the water heater replaced very soon but I'm wondering if I need to get that check valve out of there ASAP. I don't mind the bit of water from the T&P blowing off but I'm concerned about the safety of the system now that I think I know what the issue is.
You need an expansion tank
You need an expansion tank
Do we have time to wait until we replace the hot water thank or is this more of an urgent issue? Wouldn't removing this check valve (back to the way it was before) allow some pressure to be pushed back towards the well pressure tank?
fitterjohn
03-25-2017, 18:56
Yea most likely. But small expansion tanks like that are really cheap. I feel like I got one at home depot one time I the 20-40$ range, but could be wrong. Just remember the more times a relief valve pops off the greater the chance it won't reset
Yea most likely. But small expansion tanks like that are really cheap. I feel like I got one at home depot one time I the 20-40$ range, but could be wrong. Just remember the more times a relief valve pops off the greater the chance it won't reset
My worry is my lack of DIY skills and not the cost (although I don't want to pay the $500+ I'm sure a plumbing company would charge to install an expansion tank on Sunday). I've never soldered a pipe and I'm not sure this is the time to start. :). I'm confident I could cut the check valve out and use compression fittings to get it back to the way it was.
fitterjohn
03-25-2017, 19:54
Yea the shark bites aren't too bad, it wouldn't be to hard to get the check valve out, if your confident that's the problem
BushMasterBoy
03-25-2017, 20:33
I had this problem and changed out the water pressure regulator. It fixed it.
https://www.lowes.com/pd/Wilkins-3-4-in-Bronze-Female-In-Line-Pressure-Reducing-Valve/3134067
I had this problem and changed out the water pressure regulator. It fixed it.
https://www.lowes.com/pd/Wilkins-3-4-in-Bronze-Female-In-Line-Pressure-Reducing-Valve/3134067
I don't have one of those. At the most our pressure hits 60PSI due to the fact that the well pit is about 300' from the house.
My worry is my lack of DIY skills and not the cost (although I don't want to pay the $500+ I'm sure a plumbing company would charge to install an expansion tank on Sunday). I've never soldered a pipe and I'm not sure this is the time to start. :). I'm confident I could cut the check valve out and use compression fittings to get it back to the way it was.
I put in an expansion tank myself a few years ago . . . it really wasn't too hard and I'm a weekend warrior plumbing noob at best. That was especially true at that time. I just used Shark Bite fittings for that, because it was easy to do and in that application, in a utility room, I can easily monitor and if there is ever a leak I can pop on a new fitting.
Since that time I have tried to learn to solder and am much more comfortable doing that, but I would still probably keep the compression fittings on this if I ever need to work on it. Basically just a "T" off the water line and a coupling for the short pipe to the tank. Then just support it well with some strapping.
Basically just a "T" off the water line and a coupling for the short pipe to the tank. Then just support it well with some strapping.
Hmmm, a T doesn't sound too bad, I was trying to figure out how to get it fully inline with the short run of pipe that is horizontal.
Hmmm, a T doesn't sound too bad, I was trying to figure out how to get it fully inline with the short run of pipe that is horizontal.
Mine looks like this. I cut into the line to the water heater and put in the T. Then a short piece of pipe that connects into another Shark Bite that has the fitting on one end and a threaded adapter for the tank on the other.
http://i212.photobucket.com/albums/cc274/tahusker/photo.jpg (http://s212.photobucket.com/user/tahusker/media/photo.jpg.html)
Great-Kazoo
03-25-2017, 23:21
My worry is my lack of DIY skills and not the cost (although I don't want to pay the $500+ I'm sure a plumbing company would charge to install an expansion tank on Sunday). I've never soldered a pipe and I'm not sure this is the time to start. :). I'm confident I could cut the check valve out and use compression fittings to get it back to the way it was.
If you're that confident for the task, you're more than capable of installing the tank
There's no time like the present to learn.
Every home repair and improvement we did started with saying what the hell, have to learn some time.
NFATrustGuy
03-26-2017, 04:26
It's funny that you brought this up as I'm having the exact same issue. They replaced one of my 2 water heaters and a water circulation pump just before I bought my house. A couple of months later, I had the second water heater replaced under warranty. I still have water dribbling out on the floor so I put some catch pans under the various heaters and vent pipes to see what, exactly, was still leaking...
Turns out it was the pressure relief valve on the #1 water heater. Did a little reading and am convinced that I need one of those expansion tanks to moderate the pressure spikes. It's on my list of things to do, too. Gotta sit and think about the logic of the system to figure out where it should be placed based on how the 2 water heaters are plumbed to the water system.
Fun times as a homeowner.
I'm going to give this a try and I guess the worst that should happen is that I have to call a plumber in the morning.
Let me know if these steps look correct.
Leave check valve in place -
1. Turn off power to boiler system (leave recirc and house water on)
2. Drain domestic hot water line
3. Turn off house water and hot water recirc pump.
4. Drain water tank and water lines
5. Install expansion tank between check valve and water inlet of hot water tank
6. Turn everything back on in reverse order
1.5 allow enough circulation for heater to completely cool
Also expansion tank pressure needs to domestic pressure if it is too low it will fill up before any heating expansion takes place set the pressure before filling with water
fitterjohn
03-26-2017, 19:04
It's funny that you brought this up as I'm having the exact same issue. They replaced one of my 2 water heaters and a water circulation pump just before I bought my house. A couple of months later, I had the second water heater replaced under warranty. I still have water dribbling out on the floor so I put some catch pans under the various heaters and vent pipes to see what, exactly, was still leaking...
Turns out it was the pressure relief valve on the #1 water heater. Did a little reading and am convinced that I need one of those expansion tanks to moderate the pressure spikes. It's on my list of things to do, too. Gotta sit and think about the logic of the system to figure out where it should be placed based on how the 2 water heaters are plumbed to the water system.
Fun times as a homeowner.
The best way to know if you need one is if you have any check valve or backflow preventer you need an expansion tank. With a lack of back flow preventer it will just push against the city pressure and not pop or valve.
EvilRhino
03-27-2017, 17:50
I'm going to give this a try and I guess the worst that should happen is that I have to call a plumber in the morning.
Let me know if these steps look correct.
Leave check valve in place -
1. Turn off power to boiler system (leave recirc and house water on)
2. Drain domestic hot water line
3. Turn off house water and hot water recirc pump.
4. Drain water tank and water lines
5. Install expansion tank between check valve and water inlet of hot water tank
6. Turn everything back on in reverse order
How'd it go?
I took the easy way out. The check valve was installed with sharkbites so I just pulled it out and replaced it with a straight piece of pipe. No leaks and no TP blowoff since. I also figured out that the check valve on the hot water circulation has failed so once that's replaced our hot water should be working much better.
Expansion tanks are, in most cases, a lot more trouble and hassle than they are worth. They have a higher failure rate than water heaters and provide little, if any protection for the system. On a boiler, definitely yes.
Yup and just to be clear there is a properly functioning, recently replaced expansion tank on the boiler water loop.
Now I'm going to throw a sharkbite check valve on that domestic hot circ, between the circ pump and where it enters the cold line on the HW tank. What happens is when there is a large call for hot water (like bath or shower), the cold gets sucked in the reverse end of the hot water circ so you basically get hot/cold mixed at the faucet with only hot on.
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