Boiler running but water coming out cool most of the time

IceD

Hi, My name is Ethan. I have visited this site a few times before and have found some very good information here So I have decided to join to ask some questions and hopefully learn.







I have noticed lately that we are getting cooler than normal temperatures from all our

hot water faucets. The boiler seems to be running fine and the water off the boiler is hot but any faucet in the house only gets hot water for less than a minute then cools down quickly. Not all the way cold but cooler. I adjusted the mixture valve all the way hot but that didn't seem to do anything.     What can the issue be?

jim s_2

Do you have

a boiler with a tankless coil?



If so I would check to see if the coil needs to be flushed out to promote better heat transfer.



How old is your boiler?

ChrisJ

I had the same problem

A few months ago.  Had the coil flushed out and it helped some but turned out to be a bad mixing valve in the end.



The way I figured out the mixing valve was bad was I turned on the kitchen sink full hot and went down to the boiler.  The inlet to the hot side of the mixing valve stayed burning hot while the "mixed" outlet became cool.

Jean-David Beyer

Mixing valve

When the money tree blooms and I have a mixing valve installed so I can run my indirect at 140F instead of 125F (estimated), I will have in-line thermometers installed at the hot water input and the mixed water output of the valve so I can keep an eye on just such things.

IceD

-

It does seem like the mixing valve is faulty. It looks like a honeywell. After google mixing valve one of the  results on the first page was complaints about some honeywell mixing valves being faulty out of the box.



System was installed in 1998.



Anyone have a recommendation for which mixing valve to use?