Safety Valve Replaces

Safety Valve Replaces

Can an electric water heater that has been converted to oil still be used as an electric water heater?

It looks like it is being used as a heat exchanger, like another zone on the oil furnace. Cold water comes in as usual, and hot water goe out as usual for an electric heater. The top safety valve has been replaced with a pipe running to the furnace, and the cleanout on the bottom has the same. I think what happens is when the water temp in the tank drops, water is circulated to the furnace and back to the heater, and mixed with te incoming cold water. As we are heating with wood this winter, I want to know if I can just reconnect the 220V to it and heat the water as if it was still just electric, or if remodification or disconnection is necessary,
This was "converted a few years ago when the house was switched from electric baseboards to oil fired hot water baseboards. This is the water heater that was originally installed. Is it possible that coils were put ito the old tank?

If I truly understand your description, the water heater no longer has a safety relief valve, and the safety and drain connections have been tied into the boiler hydronic heating water piping. This is so wrong on so many levels.

First of all, the water in the boiler heating loop(s) is no longer potable (drinkable) water. If you've ever drained a boiler, you would see that it's kind of black and unpalatable. You now have that tied into your domestic (allegedly drinkable) hot water to the bath and faucets.

Second, you are introducing fresh, oxygenated water into the boiler system through the water heater every time the hot water is removed from the tank and cold water comes in. This will cause the hydronic heating loops to become air bound as the oxygen comes out of suspension in the water, and it will cause corrosion in the boiler, shortening it's life.

Third, without a safety relief valve, you may not be around long enough to worry about the boiler corrosion. If you've never seen a boiler explosion, they ain't pretty, & there's never any witnesses left.

Water heaters that are designed to couple to a boiler have a separate hot water coil of copper pipe inside them. The boiler water circulates through the coil, heating the potable domestic water in the tank, without ever coming in contact with the domestic water. These devices (one trade name is Boilermate) never have a secondary heat source, such as electricity. It sounds like you have a home-made wanna-be system that was designed by someone who really didn't understand how these devices (water heaters and/or boilers) work. You had better get a licensed plumber who does boilers to check out your system and correct at least 2 code violations and other bad practices before a tragedy happens.

The only way this system lets me add info is in the main answer. I doubt if anyone added a hydronic boiler coil to your water heater, as they are designed by the manufacturer specifically for the storage tank. I'm surprised it's run this long without problems, but you still never mix boiler water and potable water, ever, and the safety-less water heater is still unsafe. The "designer" (think of another name for donkey, starts with J) who did this is relying on the boiler relief valve to protect both appliances. The International Mechanical Code and local codes don't allow this installation in any jurisdiction I'm aware of. You might have the local plumbing/heating inspector check it out, but a contractor would be competent contractor would be the place to begin. Call your local BBB or the local PHCC office (contractor's organization) for the names of some good guys. They should be in the phone book or on line.