Relief Valve

[GCC]

Hello,

the main water in to the house has a Relief Valve on it. It was leaking, so I replaced it a few weeks ago and didn't think much about it. But I checked it just now and it is still leaking. SO either the new one is defective...or...?? What would cause it to leak if it isn't defective. It is a slow drip, but it is nevertheless there. Unless the main pressure to the house is too high, I am not sure why it is still leaking. It's odd to just have that problem start after 21 years in the house.

Thanks,
Greg

 

[Sylvan]

What is the pressure rating of the relief valve?

Is it ASME certified?

 

[Sponsor]

 

[Reach4]

For use as a pressure relief for thermal expect, you would expect about 130- to 120 psi. It is being used in lieu of a thermal expansion tank. As such, intermittent leakage would be normal. This is not normally done today, because it uses water.

If you install a suitably sized thermal expansion tank, this valve would likely not dribble.

A pressure gauge would tell the story. I expect high pressure while that relief valve is dribbling.

 

[Fitter30]

Need a expansion tank and gauge with fitting to put on a hose bib to measure water pressure. Any pressure over 90psi is hard on solenoid valve and faucets.

 

[GCC]

What is the pressure rating of the relief valve?

Is it ASME certified?

I think it said 70 psi. Got it at Ace Hardware.

 

[GCC]

Need a expansion tank and gauge with fitting to put on a hose bib to measure water pressure. Any pressure over 90psi is hard on solenoid valve and faucets.

Actually - the hot water heater does not have an expansion tank. Would that cause the relief valve all the way where the water enters the house to leak? If so, I’ll put one in. Was planning on it anyway when it was time to replace the hot water heater, but I’ll just do it now if that could be causing the drip there. Didn’t think about it as they are so far away and this so the cold supply to the house.

 

[Fitter30]

Actually - the hot water heater does not have an expansion tank. Would that cause the relief valve all the way where the water enters the house to leak? If so, I’ll put one in. Was planning on it anyway when it was time to replace the hot water heater, but I’ll just do it now if that could be causing the drip there. Didn’t think about it as they are so far away and this so the cold supply to the house.

Why is there a relief valve on the water line set at 70 lbs? If you're on city water pressure vary from the dead of night to mornings and evening when water usage is high. Water heater relief 150 lbs and 210° is the only relief most houses have. You need a gauge. Have a water regulating valve? If you didn't have the problem before something has changed.

Amazon.com

 

[GCC]

Why is there a relief valve on the water line set at 70 lbs? If you're on city water pressure vary from the dead of night to mornings and evening when water usage is high. Water heater relief 150 lbs and 210° is the only relief most houses have. You need a gauge. Have a water regulating valve? If you didn't have the problem before something has changed.

Amazon.com

The valve has been on the house since it was built in 2003. It’s never had an expansion tank on the water heater. It started leaking a few months back (or at least, that’s when I noticed it). Went to ACE and got a replacement for it but that is leaking, too. 70 PSI is just what it says on top of the valve. I’ll get a pressure guage and check the pressure. I do not have a regulating valve on the house.

I went out and looked and the valve says 75 psi

 

[Jeff H Young]

Its a poor and cheap method to deal with over pressure my guess is pressure goes over 70 with no regulator so bingo it spits water thats florida style its wet outside any way

 

[GCC]

I’m going to put an expansion tank in today. Went to Lowe’s and they had a 2 gallon expansion tank. The water heater is a 50 gallon water heater. I’ll check the pressure when I get home. Will 2 gallon be enough? If not, at what pressure do I need to consider returning the 2 gallon tank and trying to find a bigger one somewhere else? this was the biggest one Lowe’s had.

 

[GCC]

Ok - hopefully the pic uploaded. Pressure is around 70ish depending on when I test it. But the initial pressure when I open the balance is like 180-200 before it settles in. 50 gallon hot water heater set to setting "B", which is supposed to be around 138 degrees. Lowes only had the 2 gallon tanks in stock. I think Home Depot has a 4.5 Gallon. Should I return the 2 gallon and get the other one or is the two gallon big enough. It says it is good for up to 60 Gallon water heaters, but from what I am reading, I am worried I need the bigger one. Thanks.

 

[Reach4]

You need to get rid of the 75 psi relief valve. It is normal for the pressure on a thermal expansion tank to be well over 100 psi at times. The 75 psi relief valve is for people with wells in case the pressure switch fails.

https://www.watts.com/resources/planning/etp is a calculator for sizing thermal expansion tanks.

 

[Jeff H Young]

expansion tank alone high chance wont help do you have a closed system? like a check valve in the main , a pressure reducing valve, or a check valve out at meter? if you do a tank might help otherwise dont waste money. maybe a relief valve at 100 or 125 PSI but personaly Id opt outof the relief but dont eliminate t and p at W/H

 

[Jeff H Young]

btw 90 psi too high if you get 90 psi when its not heating water definately get that x tank and a regulator i dont like making it a more complex system but we dont want pressure that high

 

[Reach4]

To be clear, I agree with removing the valve and other stuff connected to the outdoor tee, and putting a sufficiently sized thermal expansion tank in place. 130 psi pressure relief valves seem to be pretty expensive.

 

[GCC]

So I think I will get the bigger expansion tank. Won’t hurt. The water heater has the T & P valve on it. I don’t know what is at the meter - I can look - but other than that relief valve where the line enters the house, there is nothing else. Water enters on the side of the house and I believe heads down under slab and comes out in the garage for a water softener loop. There is no other device in the line. I’ll look at the meter and see what I find there.

 

[GCC]

Left the pressure guage on overnight. The pressure reached 110 at some point.

 

[Reach4]

Left the pressure guage on overnight. The pressure reached 110 at some point.

That seems impossible if you have a 75 psi relief valve still operating. That red tattletale hand can jump due to external vibration or due to a water pressure spike such as water hammer.

 

[GCC]

Well I was wondering why it was still leaking a bit when the pressure said 60psi during the day. Maybe the relief valve itself is just bad, even though it is new?? I dunno

Here is a pic of the guage and pics the meter. Not sure if there is a backflow preventer on it or not. (Not sure what they look like at the meter)

Going to install the expansion tank anyway. May or may not need it but I think they are required by code these days anyway. Not 100% sure on that but I figure it can’t hurt.

 

[Reach4]

I don't know the range, but many 75 psi relief valves can have the pressure raised by removing that knurled clamp, and tightening the screw that is inside. But plugging or removing that relief valve would be the normal way. And simply plugging at the output of that valve would be a problem in that it creates a dead leg.