banging in pipes. hot water system?

Joseph_4

Hi. I have a customer who has a 3  zoned forced water system. They have banging at times and when  customer has put aquastat really low at 140, then it stops banging. I've bled all the zones. there is no air air in the system. i've checked with thermometer and water at highest temp when i was there was 186f. after i put aquastat up to 180.

   It sounded to me like it was flashing to steam. but the different thermometers used all indicate temps aren't near 212 and we'd need higher temps for system under pressure to turn to steam.

pressure is about 19 psi when hot

Anyone have any ideas what the cause of noise could be?

Thanks

Joe

SWEI

boiler photos and drawings?

Steam can happen at all kinds of temperatures depending on localized pressure conditions.



What kind of boiler?  Photos of boiler, circulator, and expansion tank?  How hard is the water there?

Joseph_4

its a burnham series2

never heard of hard water in far rockaway in the area. circulator is a taco 007,

3 zone valves honeywell 8043e

Steve Whitbeck

sediment

Sounds to me like you have a heavy sediment build up on the bottom of the heat exchanger. In the past I have tried many different ways to clean this build up to no avail. Most times the noise gets worse as the temp goes up. The bottom of the heat exchanger will eventually crack.