water temp / boiler rot???

superguy

2 Questions?

I've got 4 boilers that normally heat the water for a heat pump system in a 150 unit high-rise. During the summer we don't need those boilers but our mechanical contractor says we have to keep them running at 140 degrees in case we need heat. He says we can't shut them off or they'll rot. Is this true?

Also, the set point for my cooling tower is 80deg. but my sister buildings is 85deg. They have all sorts of problems with their heat pumps tripping out and my building has hardly any. If that water was cooler would it not help their problem. Our contractor says it a different system but they are both heat pump systems and i don't see how lowering that water temperature can harm anything. I'm not an engineer but the sooner you start cooling that water the lower you'll be able to keep the temperature, right? And if it can damage something can someone explain it to me because i can't get an answer from anyone else? 

 

Techman

Boiler rot

The boiler rot depends on the boiler mfrg. Shutting down boilers causes  most of them to rot,some don't. It depends on the boiler mfrg spec's. And there is usually a flue passage blockage/soot/nasty cleanup / problem also.And the reasoning for keeping the boilers running "in case you need heat" is pretty chincy, especially in the summer. The heat pump problem might be taken care of w/ 5* cooler water tower temp. How difficult is it to lower the tower temp? Try it to see if any of those "tripping heatpump" problems go away.The service calls for the lack of cooling have to be pretty expensive.You might want to repost the boiler rot Q on the " Main Wall " section.

Greg Maxwell

Boiler rot?

Ive been doing this for a long time, and I've never heard of boiler rot. Consult the manufacturer like Techman said, and I would consider pump excersising, but I dont see why the burners would have to run. Its a closed loop system, and if its piped right, the only thing you may run into with a real large water volume system may be condensing from the return water temp being low. Firing those boilers to maintain temp when you dont need it seems to me to be an aweful waste.