plumbingwaterwater-heater
I have an electric Water heater and it is starting to leak from what I believe to be the pressure release valve. I just wanted some tips on how I can fix this before the leak becomes unmanageable. The water is a couple decades old and rusty, heck the hot water inlet valve is rusted stuck open.
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You say you replaced the seats. The seat is where the usually rubber washer on the end of the stem seals against the back of the valve body. If you put your finger in the hole where the stem goes you should be able to feel the surface where sealing takes place. This surface can get scratched and allow leaks. In fact, the leak can make the scratch worse over time. Also, debris can become trapped in this space during repair and prevent sealing. So, make sure the seat is not scratched, it can usually be replaced if it is, and make sure no debris is left behind before closing up. Additionally, there is usually a washer made of paper fiber or hard plastic that sits between the valve body and the stem above the threads. If this washer is worn or missing leaking can occur at that point.
Finally, you say you replaced the seats and it got worse. It is possible the seats are not tight or are installed incorrectly, crooked, or cross threaded preventing the washer from seating. Check for that.
Good luck!
While I can't provide a definitive answer, since I'm not the manufacturer, nor do I, or have I ever worked for the manufacturer. I can try to provide a logical, fact based answer that may be close to the truth.
When water is heated, the pressure in a closed system increases. If the pressure increases beyond the tripping point of the T&P valve on the heater, the valve should open to release some of the pressure. This release usually involves very hot water and steam, released in a controlled manner. If you install a pressure relief valve set lower than the T&P trip value, The relief valve will open long before the T&P valve possibly releasing hot water and steam in an uncontrolled way. This could lead to injury to occupants, or damage to property.
It's possible that your area has not adopted the use of backflow prevention, so this extra pressure can simply be released back through the distribution system. In which case, you'll probably never see either relief valve ever open. If you do have backflow prevention in place, it's possible that this relief valve could open under "normal" conditions. The International Residential Code (IRC), and Uniform Plumbing Code (UPC) recommend pressure between 40 - 80 psi.
IRC 2009
P2903.3 Minimum pressure. Minimum static pressure (as determined by the local water authority) at the building entrance for either public or private water service shall be 40 psi (276 kPa).P2903.3.1 Maximum pressure. Maximum static pressure shall be 80 psi (551 kPa). When main pressure exceeds 80 psi (551 kPa), an approved pressure-reducing valve conforming to ASSE 1003 shall be installed on the domestic water branch main or riser at the connection to the water-service pipe.
So even under "normal" conditions, your 75 psi valve could open.
If backflow prevention has been used in your home, you are required by code to install a device for controlling pressure.
IRC 2009
P2903.4 Thermal expansion control. A means for controlling increased pressure caused by thermal expansion shall be installed where required in accordance with Sections P2903.4.1 and P2903.4.2.P2903.4.1 Pressure-reducing valve. For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
P2903.4.2 Backflow prevention device or check valve. Where a backflow prevention device, check valve or other device is installed on a water supply system using storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
While a relief valve may fit this description, the more common method is to install an expansion tank.
There are requirements for releasing pressure by way of a discharge pipe, which this valve may not meet.
IRC 2009
P2803.6.1 Requirements for discharge pipe. The discharge piping serving a pressure-relief valve, temperature relief valve or combination valve shall:
- Not be directly connected to the drainage system.
- Discharge through an air gap located in the same room as the water heater.
- Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
- Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
- Discharge to the floor, to the pan serving the water heater or storage tank, to a waste receptor or to the outdoors.
- Discharge in a manner that does not cause personal injury or structural damage.
- Discharge to a termination point that is readily observable by the building occupants.
- Not be trapped.
- Be installed to flow by gravity.
- Not terminate more than 6 inches (152 mm) above the floor or waste receptor.
- Not have a threaded connection at the end of the piping.
- Not have valves or tee fittings
- Be constructed of those materials listed in Section P2905.5 or materials tested, rated and approved for such use in accordance with ASME A112.4.1.
After doing a bit or research, I stumbled upon the NSF website which provides a lot of valuable information. It turns out, the valve mentioned in the question is indeed certified to meet ANSI/NSF 61, ANSI/NSF 61 Annex G, and California's AB 1953.
Which means it is safe for use with potable water (at least as far as lead is concerned). If you check the valve and/or packaging, you'll likely notice the NSF mark.
If you have any other fittings or products you'd like to check out, you can Search for NSF Certified Products.
This valve is not designed (or was not tested) to meet the codes and standards for a pressure relief valve on, or near a water heater. So the manufacturer was forced to mark the fitting "Not for use with water heaters".
Best Answer
I ran out of space composing an comment response to Rick's last comment, so I'm going to just make everything into an answer. First my original comment:
This heater appears to be much more than 20 years old! I agree a new installation is the best option. However, if money is tight, the valve alone should be replaceable for little money and will fix the leak, but not the other deficiencies. But with old plumbing, you are as likely to break something as to take it apart, so you may end up with a new heater anyway.
And my response to Rick's comment:
I doubt the water is very hot by the time it drips out, any hose should work, use a washing machine hose if you want one that is heat resistant in case the valve actually blows. You will need a male pipe thread to male hose thread adapter fitting to connect a hose to it. Alternately you could fabricate a drain out of CPVC pipe and fittings.
To replace the valve, take the old one out and take it to a hardware store and find a "Domestic Temperature and Pressure Relief Valve" of similar configuration. Ensure the pipe thread that goes into the heater is the same size and gender. Also insure the temperature probe is similar in length or at least is long enough to extend through the heater's internal insulation and protrudes into the tank proper. While you're there, get some pipe dope and enough CPVC pipe, glue and fittings to extend the outlet to near the floor. You don't want a family member sprayed with scalding hot water should the valve release when someone is nearby.
Honestly, you should avoid the sink/hose drain option and replace the valve, they are not that expensive. Just don't break anything removing it. If something feels like is about to break on disassembly, then maybe the hose/sink option makes sense. But for your own sake, please start saving money to replace the entire installation. It's not going to last a lot longer.