Molo
Member
I'm wondering if anyone has seen a gas valve on a heater/ hot water tank, or any gas appliance stick open and allow gas to leak?
Has Anyone Seen a Gas Valve Stick?
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Kingsotall
Plunger/TurdPuncher
What are you getting at Molo¿ C'mon, spit it out... 
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Dunbar Plumbing
Master Plumber
More than once. Leaks through the knobs.
Molo
Member
What are you getting at Molo¿ C'mon, spit it out...
No subtlety, just a basic desire to learn. What causes them to stick? I'm guessing sediment from lack of a trap, sloppy workmanship, and bad design. But what is the most common cause and is it common at all?
Kingsotall
Plunger/TurdPuncher
These old brass ones are the ones that I was told to keep my eye out for.
Supposed to replace them with redtops.
But soap solution on all gas fittings is par for the course.
Supposed to replace them with redtops.
But soap solution on all gas fittings is par for the course.
Molo
Member
I was referring to gas valves that come on hot water tanks, boilers, furnaces, etc. They are supposed to close if the flame goes out, has anybody seen them stay open and leak gas?
Kingsotall
Plunger/TurdPuncher
Oh, guess that's what rugged meant by knobs. My brain is goo. Need some rest.
Gas control valves is what this thread is about. In the great words of the revered Terry, "Anything mechanical can fail." By design they are going to always remain shut¿ Dunno.
I always wonder about appliances like washers and dryers because IMHO they are thrown together like three year olds with Legos. Yet there are millions out there just idly sitting their doing their job. Solenoids and regulators minding their P's and Q's. G'nite.....
Gas control valves is what this thread is about. In the great words of the revered Terry, "Anything mechanical can fail." By design they are going to always remain shut¿ Dunno.
I always wonder about appliances like washers and dryers because IMHO they are thrown together like three year olds with Legos. Yet there are millions out there just idly sitting their doing their job. Solenoids and regulators minding their P's and Q's. G'nite.....
hj
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valves
To answer your question, all you have to do is search for "water heater explosions". The majority of them are caused by the control failing so that the burner NEVER shuts off until the heater explodes and removes the heater and house from the area. I have only been involved with two like that, and both were discovered just before "critical mass" was reached. And then only because of secondary symptoms which revealed the problem after they were taken care of.
To answer your question, all you have to do is search for "water heater explosions". The majority of them are caused by the control failing so that the burner NEVER shuts off until the heater explodes and removes the heater and house from the area. I have only been involved with two like that, and both were discovered just before "critical mass" was reached. And then only because of secondary symptoms which revealed the problem after they were taken care of.
Molo
Member
Has anybody seen it stick open after the flame is out? Dumping gas into the room?
SewerRatz
Illinois Licensed Plumber
That is very common with water heaters that where put back in service after a flood. The moisture causes the spring loaded pilot valve to corrode in the open position.
hj
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control
That is very common with water heaters that where put back in service after a flood. The moisture causes the spring loaded pilot valve to corrode in the open position.
That may be, but since the control would be CLOSED while it is corroding, I would think it would be an unlikely scenario.
That is very common with water heaters that where put back in service after a flood. The moisture causes the spring loaded pilot valve to corrode in the open position.
That may be, but since the control would be CLOSED while it is corroding, I would think it would be an unlikely scenario.
SRdenny
Plumbing Contractor
I've had water heater pilots keep demanding gas after the flame has been extinguished. When that happens, it's time to replace the gas valve.
SewerRatz
Illinois Licensed Plumber
This is from the AHRI website, that A.O. Smith , Bradford White, and Rheem point to regarding water heaters in a flood.
Water Heating Systems
Whether your water heater is gas-fired, oil-fired or electric, if it was exposed to flood water, the unit should be replaced. A new water heater is a relatively small investment, and replacing it is fairly easy to do.
In a gas unit, valves and controls will likely corrode. In an electric unit, the thermostat and controls will likely corrode. In both types, the insulation surrounding the unit will be contaminated and will be nearly impossible to disinfect. Additionally, the insulation would take a long time to dry, leading to corrosion of the tank from the outside.
Even if water heater components have been cleaned and the unit seems to operate properly, parts may corrode in the future. Both gas and electric water heaters have a pressure relief valve that can corrode and stick after being exposed to flood water. Be sure, therefore, to replace this valve as well.
Water Heating Systems
Whether your water heater is gas-fired, oil-fired or electric, if it was exposed to flood water, the unit should be replaced. A new water heater is a relatively small investment, and replacing it is fairly easy to do.
In a gas unit, valves and controls will likely corrode. In an electric unit, the thermostat and controls will likely corrode. In both types, the insulation surrounding the unit will be contaminated and will be nearly impossible to disinfect. Additionally, the insulation would take a long time to dry, leading to corrosion of the tank from the outside.
Even if water heater components have been cleaned and the unit seems to operate properly, parts may corrode in the future. Both gas and electric water heaters have a pressure relief valve that can corrode and stick after being exposed to flood water. Be sure, therefore, to replace this valve as well.
I have a 40 gallon gas water heater in my shop that the gas valve stuck in the open position and failed to shut down, when I arrived at the house the popoff valve was blowing steam and I had to shut the gas off to get it to stop. Needless to say I installed a new water heater
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Molo
Member
This is the scenario I'm inquiring about. The flame is out but gas keeps coming.
What causes the control valve to continue to allow gas out.
hj
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valve
JNAAS2;
That is a runaway burner situation when the control fails. As long as the water supply is turned on and the relief valve functions the danger is minimal. It is when the relief valve is frozen or plugged, and/or their is no incoming water to provide flow, that explosions happen. That is different from a valve not closing when the pilot is extinguished. That happens when the pilot electromagnet malfunctions, and since that device is very sensitive, it takes a special set of circumstances to defeat it.
JNAAS2;
That is a runaway burner situation when the control fails. As long as the water supply is turned on and the relief valve functions the danger is minimal. It is when the relief valve is frozen or plugged, and/or their is no incoming water to provide flow, that explosions happen. That is different from a valve not closing when the pilot is extinguished. That happens when the pilot electromagnet malfunctions, and since that device is very sensitive, it takes a special set of circumstances to defeat it.
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