Hello all Fuel Oil boiler with indirect hot water tank experts!

I am on here trying get some suggestions on what my issue could be with my hot water. I am not trusting my repair kid any longer and want to get to the bottom of my issue and see what I can do on my own rather than pay the repair kid amounts of money to try one thing or another.

My unit was installed in 2003. I get annual maintenance done on the boiler and have it repaired as necessary. The boiler is in good shape. It has three zones. Two for home heating and one for the hot water tank. The boiler runs runs fine and sends water out to the home heating zones as expected. I had hot water issues about two weeks ago and had the repair kid come by. I had the Aquastat replaced on the hot water tank, just in case that was failing. The I had hot water for about two weeks until last night. It gets luke warm, but for the most part, it is cold. I turned up the temperature on the hot water tank and I assume the zone valve is working fine, as hot water is passing through the valve and I can feel the piping to the hot water intake of the tank is scolding hot. That leads me to believe hot water pass the valve and getting to the tank. The return water pipe is practically cool. I get no hot water. Regardless of how high I turn up the Aquastat. At this point, I am at a loss. It appears hot water is making it to the tank to heat up the water in the tank, but that heat transfer is not happening. I have taken some pictures as well, to hopefully, provide some insight into my setup, that has worked great for years. I am looking for any thoughts and tips I can get my hot water back.

Thank you for your help and assistance.

 

Sound like the boiler water is not circulating , check the zone valve end switch is closed and that the pump has power.

 

It does sound as if the pump is not running... the return pipe coming back should not be 'practically cool'.

When the water heater calls for heat, and the boiler water is cool, does the burner in the boiler fire to heat the water?

As saves said, it could be the endswitch in the zone valve not making contact...

Do you own and know how to use a multimeter?

 

I'd like to see several more pictures from a few more angles. The piping is screwy and at this point I think you have air binding.

 

Yeah, that one loop above the zone valve... that's just weird.

And you've got a leaking air vent on top of the air scoop.