Water Heater Flue Venting

[jonthedrummer]

I have a gas water heater ~8 years old. Have replaced the emergency valve and thermostat. Also have turned down the max heat on the heater. Still is venting off water occassionally. Is it time to replace or is there another fix?

[AllanJ]

Do you know when the heater vents (water from the emergency/relief valve)?

Is the water (drawn from any faucet) unusually hot at that time?

Is the temperature setting no more than halfway into the "hot" section of the dial, namely well below the "very hot" section?

When you replaced "the thermostat" did that include a part that sticks inside the tank which could become caked with sediment and not shut off the burner fast enough?

Is the overall pressure of water in your house unusually high, like more than 50 pounds per square inch?

I would not be surprised that unusually high pressure combined with the effects of water hammer (with someone or some appliance turning off water fast) could trip the water heater relief valve.

[CR500]

Does your house have a pressure regulating valve at the water entrance? Do you have an expansion tank on your cold water pipe?

My house was fine for years then the watts valve started opening on the water heater. I replaced the valved and it was still venting. I added the expansion tank and problem was solved.

[DUNBAR PLUMBER]

To know exactly what your situation is.


Thermal Expansion (http://www.watts.com/pro/divisions/watersafety_flowcontrol/learnabout/learnabout_thermexpansion.asp?catId=64#generalinfo )


High Water Pressure (http://www.msnusers.com/DUNBARPICTUREALBUM/highwaterpressure.msnw)

[jonthedrummer]

It seems to vent randomly, can't see to pin it to a specific time. Water temp does seem to fluctuate a bit, and temp is set well below the hot setting (less than halfway). Don't know the pressure coming into the house, how would I check that. System does have an expansion tank. I only replaced the thermostat - where is the part that sticks into the tank? We do have pretty hard water in our area - could that be making this happen?

Does it sound like the heater will need to be replaced soon, and should I be concerned?

[MACPLUMB 777]

See Dunbar Plumbing Posts Click On Those Links It Will Explain
Thermal Expansion To You !

Go To Hardware Store "buy" A Water Pressure Guage That You Can Screw Onto A Hose Faucet To Watch The Pressure Rise As The Heater Reheats The Water !

If Somebody Opens A Faucet Or Flush's A Toilet During This Process
It Will Drain Off The Excess Pressure And So Your T&p Saftey Valve Do'es Not Leak Or Weep !

Macplumb 777
35 Year Master Plumber
With A Ph.d In Water Heaterolgy
And A Master's Degree In The Art Of Drain Cleaning
Since Jan. 1989