Noisy check valve?

[D4dog]

Just converted an open-vent CH system into a closed system, and split into two zones whilst I was at it.

Currently, when just one zone is on, the radiators on the other zone start heating up - this is due to the first rad in the second zone being pressurised by its return pipe - this then pressurises the second zone supply, causing the others to come on. Seems that using a common return with the joins all over the place is the cause.

Fitted check valves onto the returns from rads in zone 2 - problem solved, not able to pressurise on the return line. However, they make a lot of noise if zone 1 is on at the same time. Anyone any ideas how to solve the problem?

 

[heatingman]

take the non-return valves and pipe it up properly, instead of bodging it.

 

[D4dog]

Not quite as easy as you think. This work was done by a so-called HETAS qualified engineer. But I was not happy with the vent positioned after both isolating valves, and an inadequate expansion tank, noisy radiators and frequent ingress of air. So one ting I do not do are bodge jobs.

However, this is a chalet style house, and the pipework runs in the eaves - so running any pipework is a problem, becasue the only access is a 12" square panel behind each of the exisiting rads.

Not sure what options you think there might be - most 2 zone plans show a common return, and there is no specification on where, or how the return from one zone should join the return from the other that I can find. Should it be at a single point? Becasue running a separate return is a massive job in this property.

Advice, rather than comment, would be useful!