thermal shock condensing boiler

Kevin G_2

Can you take some pictures and post them. where are you located.
Kevin G

bill h_3

thermal shock ?

hi, we recently purchased a property that has hot water heat, 3 pumped heating zones, myson radiators and munhkin boiler with t-stats, the boiler will make loud vibrations when a zone calls after being off for a while. we were told the system was only 2 years old and looks professional. any sugestions?

Chris_82

Search the site for Munch problems,...

Thermal shock is not a problem, so says the manufacturer, in fact they claim the lower the return, cold, the more efficient it is. Personally I am very opinionated about munchkin noise, in that the fan impeller shroud should be replaced AS it makes a lot of noise for the month or so just before it fails, sometimes they continue to run, somtimes they jam and stop. The problem is that you can adjust a failed fan, one in which the impeller has disentegrated, and a/the noise goes away, but you still have fan pieces or a fractured fan! It was poor design issue. Others will have you doing combustion tests as a first step but this dosent adress the fan issue. And YES new units have the same fan issue, it hasn't gone away.

Couderay

Looks

Looks can be deceiving pics on the other hand tell a story. In this case cold return is good for efficency.Being a condensing boiler its whats for dinner.Many things including the fan I suppose could be the reason,but more info is needed. Again pictures would help.

Dave Stroman

I was under the impression that the fan problems were handled. If not, why does HTP have the problem when other brands of boilers use similar materials and do not have the same problem?

Dave in Denver

bill h_3

chris, thanks for the info, i'll attempt to take pics, is the only real cure a replacement of boiler with different make/model.

Guy_6

fans

Unfortunately, once an issue surfaces, it becomes the root of everything that happens to a boiler. In this case, I would be far less likely to suspect the fan, and more prone to looking toward a flow issue. Are there zone valves on the system? Is the circulator sized correctly? Is the piping the correct size and is there a primary loop?
There is a lot of heat left in the boiler even after the flame shuts down; if the flow was insufficient to begin with, the water in the boiler is hotter than expected. Upon shutdown, the latent heat boosts that up even further, causing "flashing", which is literally steam.

Chris_82

Guy,??

Munchkins can not flash.

Brad White_9

Then what explains

the dwarf near where I work who was arrested for doing just that? Huh?