A quick question. When my floor calls for heat in the pole barn the pump kicks in and begins moving hot water through all that pex I laid. My question is the water temp in the boiler drops 20 degrees until the pump turns off. Is this bad for the boiler? I am running a central boiler maxim 250 and burnt corn until tonight (switching to pellets because of cost). The floor heat works great and highly recommend it.

Probably not

It Depends

Should be ok as long as you don't operate for extended times in condensing temperatures

If you do, you end up like me.

I didn't write that

So what should I do to keep this from happening? Possibly run a small low volume pump that circulates all the time to eliminate the rush of cool water going to the boiler. I sure don't want to end up with a problem like yours jabbott.

before you aspire to follow in the footsteps of our host

What supply and return temperatures at the boiler are we chatting about?

central boiler 250 maxim is set at 176 and when floor pump kicks on it goes down to around 154 and gradually builds back up before floor pumps kicks off again. Of course when the pump turn on at first it is pushing water that has cooled to probably 85 to 90 degrees into the boiler. That is what brings the temp down. Is the constant expansion and contracting going to hurt anything?

nope

thanks sting

Sting wrote:


Hahahahaha!

It isn't so much the expansion/contraction as the corrosive nature of (in particular corn?) gasses, correct?

Wouldn't adding a buffer tank make this problem go away?

--ja