Water Heaters - Moving propane valve to nat. gas tank?

I have a propane operated 40 gal water heater by American. The tank is much older than the valve and rusting out. There are plenty of good newer used water heaters available but most are for natural gas. Am I correct that water heaters have the same thread size for the valve and I can easily switch valves, put my good propane valve in place of the natural gas one that comes with the water heater? Or are there more specific requirements that aren't apparent.

Any suggestions for me...

jc

JC, you state "valve", and I am sure you mean "orifice", is that correct? Most, if not all, newer water heaters either come set up for propane or natural gas, or have the conversion kits included. If not, your gas supplier can accommodate you in setting your heater up properly.

I meant the entire valve, which screws into the water heater. The valve to which the gas is connected, that has the pilot hold-down button, and the temperature control. Perhaps I should have said "control valve". I wasn't trying to convert a natural gas valve to propane, just switch it with my good propane control valve. Because, as I mentioned, it's easy to find a good used natural gas water heater, but very rare to find a propane one.

jc

continuing...I have converted gas space heaters, but didn't realize that water heaters could also be converted, so you've given me another option. But it is much easier to just switch the control valve...if it fits. Which is the basis of this thread, can this be done!

jc

All water heater manufacturers that I know of have very specific language which PROHIBITS converting a unit from nat. to LP. Lots of reasons why it is not a good idea. Buying a used water heater.....that in itself is a bad idea to start with/

Lots of reasons?...please name them. Then go on to tell me why I shouldn't buy a used water heater when I can't afford to buy a new one.

jc

594, maybe I was mistaken, but the guys that installed one for me once had a kit they just changed what I thought was an orifice out and let it run on propane. I asked them about it and they said they did it on almost all tanks in our area since there was limited natural gas supply. JC: I understand your dilemma, but you may spend as much on modifying the used tank as a new heater would cost, and you may not be assured of a quality tank since you can't see inside it. Just looking out for downstream problems.

Chandler, thanks for that information. I've replaced orifices in space heaters and the kits are simple and cheap. There is also a pressure difference that has to be adjusted for. I didn't know that was possible on water heaters, nice to know it now.

It's no dilemma for me...I have a working, free, control valve on my old water heater and I remember when I installed it, it was a simple screw in job. I can buy 2-4 year old used water heaters for $50-75. New water heaters, 40 gal size, cost what? $300-400. And buying brand new items contributes to global warming and the general waste stream that our society seems to wallow in. Then there is the quality aspect...every year manufacturers produce lower and lower quality goods and then do everything possible to avoid honoring the warranty.

It's not a dilemma at all, I just want to make sure there isn't a mechanical or engineering reason it shouldn't be done (different size fire chamber?).

jc

Lots of reasons?...please name them. Then go on to tell me why I shouldn't buy a used water heater when I can't afford to buy a new one.

jc

Here is the document from Rheem: http://waterheating.rheem.com/content/resources/documents/tech%20bulletins/1400%20Series/1407.pdf


You would probably void your homeowners insurance , you would be committing a prima facie code violation, since all codes REQUIRE compliance with manufacturer's instructions, and you may be putting your home and family at risk. I don't make this stuff up. Your choice.

I question the logic of buying a used heater, since what can be the life expectancy of a used one? You might stumble on one which for one reason or other is just young and in good shape, but odds are against you. I would also check with your code officials, because installing a heater which is older than July 2003 ( non-FVIR) may not be allowed.

If you go ahead with your project despite what ever warnings there are, remember one thing. In addition to changing the gas control valve, the pilot and burner orifices also have to be changed.

Also don't forget the thrust nut on the burner tubing that screws into the control is left hand threads for propane. Which may complicate matters.

I also question the wisdom of buying a used gas water heater. Why are they available if they still work OK? I don't know of many people who change out gas water heaters until they leak or otherwise go bad. Also, buying a new gas water heater gives you the latest in safety features, such as the system to prevent ignition of flammable vapors.

I also question the wisdom of buying a used gas water heater. Why are they available if they still work OK? I don't know of many people who change out gas water heaters until they leak or otherwise go bad. Also, buying a new gas water heater gives you the latest in safety features, such as the system to prevent ignition of flammable vapors.

You know that, I know that. It all boils down to $$$. Many don't understand that when they try to save a few pennies, they end up spending dollars in the long run.

I dont know But Id think some one is nuts to use a old gas hot water tank. Any that we have taken out for one reason or another have been so heavy. The lime and calcium in the water builds up around the flue Pipe in the heater And turns in to a rock like around that flue pipe that heats the water. So the older a tank is the more gas you have to burn to heat the water.:wall: