Do tankless coils wear out?

Joel M

By tempering valve do you mean the mixing valve that mixes boiler water with cold water to prevent scalding? Mine was replaced about 3 years ago. It could be going bad again. I don't know what a flow limiting orifice is.

Joel M

Should a 13 year old Weil Mclane tankless coil be losing its heat output? I know ours dosen't put out hot water like it originally did.

mark schofield

scale

From what I understand, the domestic hot water side (inside)of the coil can become clogged with scale after a time, depending on the quality of and chemicals in your domestic water supply. The coil can be flushed with a descaler to increase the flow. The coil would of course have to be isolated from the water supply, both in and out. I recently installed a new boiler with tankless coil; and put ball valves and Ts with plugs to isolate the coil and then flush it with vinegar or muriatic acid if/when the output decreases. Hopefully a pro can give you more specific steps or information. Mark S.

LarryC

Tankless coil problems

I'm just a home owner, but when I had problems with our tankless, the tempering valve internals needed to be replaced. Also, does your setup include a flow limiting orifice? Check that out too.

Larry C

LarryC

Tempering valve

"By tempering valve do you mean the mixing valve that mixes boiler water with cold water to prevent scalding?"
Yes. Try adjusting the valve thru its operating range and then put it back where it was initially set. It might have some debris built up inside on the internals.

"I don't know what a flow limiting orifice is."
In our system it is a silver cylider that has a flow rate stamped in like 3 gpm. It limits the flow rate thru the coil to ensure the water gets heated up enough.

Do you have hard water in your area? If so, you may have scale inside the coil as someone suggested. Is there some sort of strainer or filter in the drinking water system before the water heater? If so, has it been flushed or filter element changed?

Good luck,

Larry C

Joel M

I did move the dial on the mixing valve thru its range already. I will check tonite for the flow limiter. Our water is not hard as far as I know, it is city water, nobody around here has a water softener. Thanks.