Heat Exchanger Piping

DanHolohan

the water's not draining from the exchanger shell when the steam is off. Is there a vacuum breaker installed in the shell? You'd think that the Hoffman 75s would let air back into the shell but a lot depends on where they're installed. They really should be on the outlet of the exchanger so that they can remove all the air from the shell on each call for heat.

tom_20

Heat Exchanger Piping

I have a customer with a garden apartment complex that has 5 boiler rooms. They have hydronic heat.
Several years ago, the boilers were replaced. Federal FST 50 steam boilers were installed with Lindy SC8B2-72 heat exchangers mounted about 2 feet above the boilers. The exchangers are mounted level and are fed with a 4 inch pipe. The drain on the exchanger is 1inch and is tied into the bottom of the boiler. There are 3 Hoffman #75 vents piped off the top of the exchangers. It appears that there has been trouble with banging in the exchangers since the initial installation. A couple of the boiler rooms have since had a trap and condensate pump installed which has alleviated the problem. Another exchanger was repiped so the 1 inch condensate line drains into the skim line. This seems to work as well. All boilers are very sensitive to the water line. If there is a little too much water, there
is more banging.The particular room I was in did not bang while I was there. The super of the building claims that the banging starts as soon as the boiler starts steaming, with no pressure on the gauge.
I haven't been able to find any information on a proper piping scheme for this application.

I would appreciate any comments or insight into this situation.

Thanks for your help.