DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Plumbing (http://www.diychatroom.com/f7/)
-   -   water heater relief valve dripping (with gauge readings) (http://www.diychatroom.com/f7/water-heater-relief-valve-dripping-gauge-readings-93601/)

ziguan 01-26-2011 05:57 PM

water heater relief valve dripping (with gauge readings)
 
water heater relief valve is leaking. so checked the pressures with a gauge.

95 - cold water
80 - from water heater
150 - from water heater, when water is heating

1. there is a water pressure regulator next to the water meter. is that the reason water from the tank can't go back to the system?

2. is the cold water pressure too high?

3. will lower the pressure from the pressure regulator fix the leak?

4. should I put in an expansion tank? (and the pressure of the tank should be set to the same as the cold water pressure?)

thanks in advance for any reply.

John

bob22 01-26-2011 07:54 PM

Yes: should I put in an expansion tank? (and the pressure of the tank should be set to the same as the cold water pressure?)
Pressure should be around 60 psi or so, 80 is too high IMO. Need to adjust your pressure regulator.

Bob999 01-26-2011 08:11 PM

Quote:

Originally Posted by ziguan (Post 578567)
water heater relief valve is leaking. so checked the pressures with a gauge.

95 - cold water
80 - from water heater
150 - from water heater, when water is heating

1. there is a water pressure regulator next to the water meter. is that the reason water from the tank can't go back to the system?

2. is the cold water pressure too high?

3. will lower the pressure from the pressure regulator fix the leak?

4. should I put in an expansion tank? (and the pressure of the tank should be set to the same as the cold water pressure?)

thanks in advance for any reply.



John

1. Yes
2. Yes--Recommend 60-65 lbs. You may find the pressure regulator needs to be rebuilt--rebuild kits are usually available but sometimes it is easier and better to just replace the valve if it has failed.
3. probably not--you will probably have to replace the pressure relief valve.
4. Yes

ziguan 01-26-2011 11:10 PM

thank you for the replies.

have lowered the pressure to ~60 now. so the regulator does work.
but now I know why the previous owner has set it so high (we've just bought this house). the water flow is really bad.(just took a shower).
could someone please tell me what kind of damage can happen if the water pressure is set too high? (assume I've added an expansion for the water heater). I mean, there must be lots of homes that don't have the regulators. right?

the relief valve is suppose to release(?) at 150 psi from the label, but after lowering the pressure to ~60. now it reads ~120 when it's boiling water. it still drips. does that mean the relief valve is bad??

I believe the Water heater is 90 gallon, what size of expansion tank should I buy? any brand/model would you recommend?


John

AllanJ 01-27-2011 08:30 AM

90 PSI is too high for a household water system.

Excessively high pressure increases the chance that something may give way. A not so well soldered pipe joint could come apart. The hot water tank on on average one of the weak spots because it gradually rusts out, and excessive pressure means a greater chance of a sudden flood as opposed to a slow leak giving you warning.

Thurman 01-27-2011 05:53 PM

Interesting that so many of you state that water pressure for a home be in the 60#-65# range. This is what I have been taught for years. BUT- -in the last few months I have had calls to one particular area of the next county for "sudden & mysterious" water leaks within residential plumbing. After realizing the all these calls were in one particular area, I put a gauge on the home's rear faucet and asked the homeowner's to take the readings for me. ALL of these homes consistently had over 85# of water pressure during various times of day and night. I went to the local County authorities about this, with the recorded records, mainly to ask what they attempted to keep the water systems nominal pressure at. I really liked their reply: "As high as we can get it, so the pumps don't have to run as much". When I mentioned about the leaks within home in this one particular area it was suggested to me to start selling and installing WPR's on homes. Not good advice to me from them.

ziguan 01-27-2011 06:57 PM

thanks for all the info.
so even the water flow is kinda slow in the house now. we should still keep it under 65? or any other places we should check?

bob22 01-27-2011 08:30 PM

What kind of piping: galvanized, copper?

ziguan 01-27-2011 10:39 PM

Quote:

Originally Posted by bob22 (Post 579262)
What kind of piping: galvanized, copper?

copper.

now I have measured the pressure again and am a bit confused.
I've connected the gauge to the water hook up for the washer and have noticed that pressure has increased when the water heater is heating(jump from 60 to 85).
I guess that's caused by the expanded water? should I shut off the water to the water heater and wait a day before measuring it? (that will be the real water pressure??)

Bob999 01-28-2011 08:05 AM

When there is no flow the pressure will be the same where ever you measure it because the pressure equalizes everywhere in a closed system (and your pressure reduction valve makes your system closed).

Low flow is caused by restriction(s) in the plumbing system that has good pressure in a low flow situation.

Do you have any filter in your water supply system? If so remove the cartridge (if it is a cartridge type) and check to see if flow is increased. If a filter has a bypass valve put the filter is bypass. Dirty or plugged filters are a frequent cause of flow problems.

If no filters then you need to begin to check to see if every faucet has low flow. If some have good flow then you can begin to isolate where the restriction is. If all have low flow the restriction point will be common to all. For example the pressure reduction valve might be a restriction point if it is not properly sized or if it is failing.

bob22 01-28-2011 11:12 AM

Your pressure will go up when water heater is on as heating the water causes expansion (thus the need for expansion tank) and increased pressure. I believe expansion tank pressure on install should be at the base level, 60-65 psi that your water is at when not being heated.


All times are GMT -5. The time now is 09:38 AM.