UFH manifold issues

[cully]

Please advise,
I am finding the following issues with some of the 10 circuits on my 17 year old UFH system:
Of the ten circuits (seven zones) there are two actuators that are allowing flow (max 1 lt/min) on no demand and two flow valves that are showing restricted flow on demand (around 1<2 lt/min)
I checked and cleaned the flow valves about 18 months ago and the question now is considering the age of the system is it time to change the flow valves and actuators?
The system has always had more inhibitor in the water than is required
The other consideration is the manifold pump output but when the heat is demanded apart from the manifold pump there is the boiler pump and a second grundfos pump adjacent to the boiler (there are two other circuits in the system as well as the UFH)
What do you think?
Thanks
Paul C

 

[ironsidebod]

Regarding the first issue it's probably the pin valves need replacing if the actuators are passing. I've had to do a couple on ours but one actuator had gone so wasn't able to close properly. You don't mention what manifold you have but the pin valves on our Uponor are about 6 quid and an actuator is 24 quid. They're easy to change is you have the correct isolator valves on the manifold.

Flow valves are easy to change to but again, depending on the manifold you might have pin valves under these or self contained flow meters.

 

[cully]

Thanks for your reply, the flow meter / valves are on a polyplumb manifold listed at around £13 ea so I will get some after the holiday period.
The actuators are Honeywell Z100 BGE that are now replaced with an updated version MT4 230S-NC (£40 incl del) and there are not many listed on Google so I will be doing some research on these over the next few days
Paul C