Chemical flush cases sticking TRVs?

[whistler]

Had a new boiler install yesterday with chemical flush. I have Honeywell evohome radiator valves and today noticed most zones were getting too hot. I checked the valves and couldn't hear them turning. They appeared to be stuck fully open. I googled the problem and found that chemical flushes can cause sludge to jam the trv's. I think I've managed to clear them all now but just wondering if this is a common problem?

 

[Wayners]

They jam in summer with lack of use.
Either fully open for months of fully closed.
Come autumn people find they ate jammed.
Reminds me I need to go service mine and mother in laws before I get complains...

 

[Madrab]

found that chemical flushes can cause sludge to jam the trv's.

Cant say I've ever seen that when flushing out a system. Was the system really bad?

If the rads were that bad that there was excessive amounts of sludge that had to be flushed clear, then could some get caught on the valve seat ... possibly. If the system was that bad to start with though, then it would have needed a considerable amounts of cleaner, filling and flushing until it ran clear. If the system had been that bad to start with though then a gravity/mains flush may not have been the best solution to start with without removing and flushing the rads clear outside.

Stuck fully open though, can't say I would have looked to the flush or the sludge as the cause of that. It does sound more like TRV's that haven't been used in a while. How were they 'cleared'?

 

[ericmark]

They jam in summer with lack of use.

Really, I know EvoHome is an old system, but all my TRVs exercise once a week. So only with mechanical TRV heads should there be a problem with sticking.

I have had problems with discharged batteries at the start of the year, which reminds me to get a stock of AA cells.

 

[Wayners]

Interesting.
I didn't know they cycle.

 

[ericmark]

Interesting.
I didn't know they cycle.

Maybe Honeywell EvoHome don't? But Energenie, eQ-3, Kasa, and Wiser all have an anti-stick cycle built in.

 

[Mottie]

I leave all my TRV's open during summer and run my heating for 15 minutes or so once a month with the pump on highest speed just to keep things moving. When it starts to get colder (anytime soon now) I remove the TRV heads and push the pin down a few times to make sure they spring back up. I then set the TRV's to what I want them to be at.