Water heater pressure relief valve leaking. Advice needed

davenApril 19, 2014

Recently purchased a condo that has a gas water heater with power vent. I discovered a rubber hose connected to the pressure relief valve downspout and there has been water leaking from the valve.

What is the probable cause of this and what is required to fix this? I have never seen this happen in any other water heater.

Thanks,
Dave

Thank you for reporting this comment. Undo
justalurker

The valve you are talking about is a pressure relief valve (PRV). It is a safety device to prevent WH explosions.

Either the valve is bad and needs to be replaced with EXACTLY the same spec valve despite what a vest wearing know it all at a box store says... "this one fits everything".

Or you have a closed plumbing system and you have a thermal expansion problem that needs to be corrected NOW.

If you have a closed plumbing system, and that has been code since the 90's, there should be a small thermal expansion tank installed proximate to the WH. These tanks have a bladder that may have failed and the tank must be replaced.

OR... you have a closed plumbing system and there is no thermal expansion device installed, which is not uncommon, and there needs to be one installed. In this case the PRV is acting as a thermal expansion device and it is NOT intended to.

Here's some light reading on thermal expansion... http://www.watts.com/pages/learnabout/thermalExpansion.asp

If this seems beyond your skill level call a plumber... and do it SOON.

    Bookmark   April 19, 2014 at 12:53PM
Thank you for reporting this comment. Undo
saltidawg

Very common for sediment to get under the valve and cause leakage. Lifting the valve manually can cause the seat to clear, however it is also possible to scald oneself or have a major blowdown if the valve does not shut.

Some people manually lift the relief annually to prevent this very thing.

The thermal relief is required whether or not you have an expansion tank.

    Bookmark   April 19, 2014 at 5:30PM
Thank you for reporting this comment. Undo
daven

The heater is off so I will try lifting the valve tomorrow.

    Bookmark   April 19, 2014 at 6:25PM
Thank you for reporting this comment. Undo
justalurker

PRV valves are not designed for intermittent use. Whether the cause of the leak is dirt or excess pressure is irrelevant. For sediment to get under the valve (in the valve seat, the valve had to be opening and that is indicative of a bad valve or excess pressure in the plumbing system. The valve should be replaced and the cause of the valve failure identified and repaired.

Thermal expansion is one of the most ignored and misunderstood plumbing conditions by both homeowner and handyman(woman) types. Thermal expansion problems are common and easy to resolve.

    Bookmark   April 19, 2014 at 7:33PM
Thank you for reporting this comment. Undo
saltidawg

Er, ah, OK... as I said, "Some people manually lift the relief annually to prevent this very thing." Note the words 'annually' and 'prevent.'

Additional, by design of this valve and its significant "blowdown" it is not dripping a few drops to prevent an overpressure situation due to a solid system.

This post was edited by saltidawg on Sat, Apr 19, 14 at 20:13

    Bookmark   April 19, 2014 at 8:10PM
Thank you for reporting this comment. Undo
jakethewonderdog

Hey Dave,

As mentioned before, the expansion tank (or lack thereof) may be the source of your problem, as Lurker has mentioned. You will want to resolve that problem if you have it.

In any case, replace the valve. It's just not worth dinking with it.

But something that wasn't said - the hose on the outlet pipe really isn't kosher.

The pipe coming from the PRV must not be reduced in size from the outlet of the PRV (or have any kind of valve on it). It should terminate near a drain and it must be visible if there is a water discharge.

    Bookmark   April 20, 2014 at 10:00AM
Thank you for reporting this comment. Undo
homebound

I just had a customer who's newly installed hot water heater began to leak after 3 months. (Turned out the Installer kept the existing expansion tank when he installed the new tank.). PRV was dripping about 1/2 gallon/day. New expansion remedied it. (Work done by a pro.)

    Bookmark   April 21, 2014 at 10:16AM
Thank you for reporting this comment. Undo
saltidawg

daven,

what was the final determination?

SaltiDawg

    Bookmark   April 23, 2014 at 12:14PM
Sign Up to comment
More Discussions
Kitchen sink faucet lost its water pressure
I did some preventative maintenance this evening by...
yam2006
Fleck 5600SXT 64k Setup
Well I recently had a new water softener installed...
SheeB
Quality of what general contactor is providing
I don't feel qualified to inspect my new home currently...
Larry Lotter
Costco Water Ridge Dual Flush -- Need reviews
Any more reviews on the dual flush Water Ridge toilet?...
smudgecat99
fleck fusion high flow metered water softener
Our Culligan has died and we aint too heartbroken about...
vossner
Sponsored Products
Single-Track Ice Luge Mold
$11.99 | zulily
Contemporary Indoor/Outdoor Area Rug: Chandra Rugs Zeal Charcoal 7 ft. 9 in. x
Home Depot
Two Tier Corner Shower Basket
Signature Hardware
Oxford Bronze Large Down Outdoor Wall Mount
$219.90 | Bellacor
Oil Rubbed Bronze Whitehaus WHKTSL3-2200 Deck Mount Lever Kitchen Faucet
$599.00 | Blue Bath
Tommy Bahama Island Estate Veranda Swivel Outdoor Bar Stool, Patio Furniture
FRONTGATE
Serena & Lily Pondicherry Headboard
Serena & Lily
Safavieh Poolside Cream/ Green Indoor/ Outdoor Rug (5'3 x 7'7)
Overstock.com
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™