Munchkin Boiler/hotwater

WalkerWeeks

I run a building with 39 munchkin boilers. All boilers have a air handler and a 30 gallon stainless steel hot water tank. i have 2 boilers that are giving me problems, even had a professional come out and he was stumped.

both boilers have NO fault codes.. heat is working great! the hot water not working properly, i can get about 10 mins of hot water and thats it. After 10 the water turns ice cold. the circulating pump going to the hot water tank has been replced and runs normaly. the old pump ran normaly before as well but im down to replacing everythng at this point. i feel that i should get more than 10 mins of hot water.

both boilers are 80m

Rich_49

What tank is this and is it a storage tank or an indirect heater ? Has it ever been serviced , I mean boiler and tank ?

Boiler makes heat with no problem and it does make or send some hot to the tank because you still get 10 minutes of hot water . I'd venture a guess to say your tank has an issue . Whether it be a control issue , limed up HX , or something other will require more information .

Where are these tanks located ? When did the problem start ? What temp are you storing at in the tank ? Is there a mixing valve ? Can you send pictures of the 2 questionable set ups ?

WalkerWeeks

The tank is an indirect heater. Its all located in a closet. The problem started about a week ago. The temp for the tank is at 119 degrees. I do not have pictures of them at this time. They do not have a mixing valve.

hot_rod

How old are the tanks? The coils can lime up and reduce the output and recovery time. It is usually a gradual decrease.
How hard is the water?
The tank liming up has a lot to do with how much water has passed through them, hardness and operating temperature. I suppose with that many units DHW use varies.