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Author:
ddbbp (KS)
Temperature Relief Valve on water heater.
I don't appear to have a full on drip/leak. I found one tiny drip of moisture though on the floor directly under the discharge. There is very slight moisture inside the pipe from the valve too.
The heater is less than a year old.
Do these valve ever weep condensation?
The valve is pretty warm to the touch too. The water is left at 130.
I do have a closed system and a expansion tank. If a tiny dribble occurs because of thermal expansion, should that be considered normal?
Should I just consider it condensation until I see real drippage?
Edited 2 times.
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Author:
ravi102769 (VA)
No it's not normal. You should check your water pressure with a gauge to ensure that the pressure reducing valve is working. The next step is to check the pre-charge on the expansion tank, you want it to match the incoming water pressure, check it when the there is no pressure in the system. If all that is good, replace the PRV.
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Author:
ddbbp (KS)
This has led me to think I have a pressure problem.
We do not have a pressure relief valve as far as I know none for the life span of the house 60+ years.
I have water softener. With new filter in water filter and meticulously clean softener.
I checked pressure at first cold spigot closest to main and it was showing fluctuation around 80psi. I even registered 100 at one time. That is unsoftened water. On another untreated spigot outside at the end of the system I was getting similar readings. Both of spigots woith the high pressure were frost free silcocks.
While I was registering these high readings, I noticed normal pressure at the water heater 60 psi. I never got the high readings on the treated water of the water heater inside the home.
I flushed the tank and drained the system completely and showed 50 psi on the exapansion tank which is on the cold line.... I then pumped up to 60.
When I turned everything back on, the outdoor spigots only were showing higher pressure.
The town told me they are not doing any work in area and I checked my neighbors outdoor spigot and it was spot on 60 psi.
Theres a checkvalve right after the meter.
What could my problem be?
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Author:
ravi102769 (VA)
The first thing to do is to control the water pressure with a pressure reducing valve. That will either solve the problem or give you a starting point. In many towns the pressure will spike at night when water usage is at a minimum.
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Author:
ddbbp (KS)
There has never been a PRV here in 60 years... don't see why it would be needed now. A few questions:
The pressure at the water heater is spot on 60. I tested it both cool and while heating and it never changed even while it was firing. So if the Temp Rel. Val on the heater was weeping or passing, then the pressure would have to rise in the tank right?
So what could cause the two outside spigots to raise and not the water heater pressure to change?
If my pressure was 60 and my expansion tank was only charged to 50, would that have any or little effect on any of this?
Also failed CHECK VALVE (Backflow preventer) at my main, cause intermittent high pressure?
One of the times I got the extreme high reading, my Water Softener was regenerating.... could a softener in operation cause higher pressure? (I ask because the two faucets I measured at that time were unsoftened supply water).
Edited 5 times.
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Author:
hj (AZ)
It is NOT condensation, but without seeing and testing it, we cannot tell you what it is, or if there is something than needs repairing.
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Author:
ddbbp (KS)
any help or answers to my (many) questions would be appreciated. I sure hate to be a pest, it probably comes off that way.
Can you at least rule out the check valve? (the only piece other than the meter owned by the town I live in).
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Author:
KCRoto (MO)
The expansion tank should be a couple psi higher than your static pressure in the system. When thermal expansion starts, it raises the pressure in the system the couple of psi, then the excess pressure is absorbed by the expansion tank. If the pressure is too low on the tank, it compresses with normal water pressure, then the expanding hot water doesn't have anywhere to go except out the T+P valve. In some areas, they increase the pressure in the mains to feed more water to a wider area without having to replace the water mains. If there have been any new water towers built in the last year, that could lead to the same problem.
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Author:
ddbbp (KS)
These will help me proceed today with the problem:
1. can the mandatory check valve (backflow preventer) installed right after the main cause high pressure?
2. Can I rule out Thermal Expansion if:
a. The high pressure is not relieved when opening a tap.
b. There is no pressure rise when measured at the water heater while its heating or directly after it has heated?
3. Can a water softener, during regeneration or directly after cause high pressure, perhaps from air in the pipes?
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Author:
packy (MA)
1) the backflow can not cause high pressure but the heating of the water can. the backflow stops the extra pressure from going out to the street.
2a) the pressure must be relieved when you open a faucet . (law of physics) volume decreases and pressure decreases..
2b) i don't understand this question?
3) does not create high pressure
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Author:
ddbbp (KS)
2b-
If I measure the pressure on the water heater valve while the heater is on or off I do not get any pressure rise. Its been spot on 60. The two other outdoor spigots where I was getting the high readings yesterday afternoon have also stayed spot on 60 for the last 12 hours (over night).
That's with or without the water heater running.
Which brought me to the idea that it was from the water main I was getting a spike. Or pumping up the ET from 50 to 60 was the issue? I cannot recreate the high pressure with any combination of the heater on or off today.
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Author:
bernabeu (SC)
'work' the relief valve (T-PRV) being careful not to splash yourself with hot water
GENTLY, repeat GENTLY, tap it to reseat valve
if problem returns - replace valve
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
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Author:
packy (MA)
the higher the pressure is in the expansion tank, the less effective it is... it is supposed to absorb excess pressure not maintain it like a well tank.
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Author:
ddbbp (KS)
If there is no pressure rise today in the house while the water heater is heating or just after it has heated without water being used, then is it safe to rule out thermal expansion now?
It has been at 60psi overnight and into today... Ive run the heater many times. How likely is what I saw yesterday on the cold water supply a pressure spike from the town?
"the higher the pressure is in the expansion tank, the less effective it is... it is supposed to absorb excess pressure not maintain it like a well tank."
Its equal to what our pressure is right now/usually is.... 60. But rereading your post, that implies when I only had 50psi in it, your saying it was more effective? Could that 60 vs. 50 differential in the tank really cause a 150 psi trickle from TRV? Figuring it would make no difference other than the weight of the water inside... it would still be providing "breathing room".....
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Author:
ddbbp (KS)
I think I created a monster here with this thread, I am getting a bit long winded. So I will conclude with the assumptions I have gathered so far.....
these are true or false statements:
1. If there is no pressure rise at either the water heater valve or the two cold spigots during or directly after the water heater has been heating than what I saw IS NOT thermal expansion and most likely came in from the street.
2. In a closed system, if increased pressure is seen and a spigot is opened and the high pressure does not relieve itself, than it is coming in from the main. If the high pressure does relieve itself then it is thermal expansion.
3. A malfunctioning backflow preventer/check valve at the meter would not cause high pressure.
4. A water softener would not cause high pressure but could cause low pressure if it is fouled. This includes during a softeners regeneration cycle when the thing is in bypass mode.
If your still with me and have a moment to answer I sure would appreciate it.
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Author:
packy (MA)
1) first part-true
second part
2) for the most part-true-maybe
3) true
4) true
i attest these statements to be factual
Hamilton Burger esq..
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Author:
KCRoto (MO)
You said you increased the pressure in the expansion tank from 50psi to 60 psi, and that makes a world of difference.
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Author:
ravi102769 (VA)
As a starting point why don't you just replace the tprv. They are not expensive. It's tough to troubleshoot without being there.
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Author:
ddbbp (KS)
Came to this conclusion.
I pumped up the small 2 gallon expansion tank for my 50 gallon heater. All seemed fine but a few days later it spit again. When I saw the water I quickly checked pressure and it was up high again like the last time.
I then checked the pressure on my neighbors outdoor spigot and it was normal at the same time mine spiked.
I let my faucet run for a few moments and checked again and it had slightly lowered.
That makes me think the tank was bad (although it was holding a charge).
I replaced the tank with a 4 gallon one and I hope that rectifies this problem.
Did I make a logical choice for replacing the tank?
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Author:
bernabeu (SC)
couple of $$$ well spent
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
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