Noisy Thermostatic Radiator Valves

[Jimster]

Hello, I have a few thermostatic radiator valves on my central heating system (Combi Boiler) which will not stop making the pipes bang unless I turn them on full. What is causing them todo this? The valves are branded as Wickes own, it this the problem are they rubbish? I have bled all the air from the heating system (no much was in there), but this didn't help.

http://www.jims-renovation.co.uk

 

[ollski]

Probably just cheap, nasty valves but may well be on the wrong pipes, ie flow and return.

 

[Jimster]

I'll check if there on the flow or return, which should they be on?
I thought they may just be cheap and nasty, I will problery get my new ones from screwfix, as they seem quite cheep there. But which one's should I go for?
http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=12868&id=19052
http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=12983&id=10023

Or should I go for somehting else?

 

[ollski]

for me personally I always use the danfoss ras c2 from plumbcenter if a customer has no preference, but none of the honeywell valves have ever had any come back to me either.
If you turn the valves up to fully open and then switch on your heating you will need to go round feeling the pipes to your rads....the pipe that warms up first is the flow the other the return. Your rad valves should have an arrow on them indicating which way the water must be flowing and just match it up.

 

[ChrisR]

This is a vexed question causing ag on another forum. If the valkves have two-headed arrows on them it shouldn't matter whether they're on flow or return. BUt it often still does.

First thing to try after that is to turn down the lockshield valves (Other end of rad). Half a turn open is probably all you need. That will control the flow but not the pressure. Either can give the noise. If you have one or more rads without TRV's, which you should, make sure those are wide open.


Manufacturer's will say you need to fit an automatic bypass valve (Just one, usually somewhere near the boiler). That will reduce the pressure. COmbi pumps are 6 metres head (pressure) and most small systems only need a fraction of that. ABV's cost about £22. Don't bother with Screwfix's cheap valves, theyre no better than Wickes'.

 

[jonathanhall]

I have recently had the same problem, i moved in to a 1950's house with abaxi back boiler. i inteneded to rent the house out so as a legal thing i fitted TRV valves on all rads execpt 1. to keep the job with in budjet i stumpbled across some cheap valves on ebay. after fitting the valves i had nothing but banging on the system when the heating got up to temp.
for a whole year i pout it down to the old boiler being broken or on its way out, so we saved upo and fitted a brand new combi boiler. This made the problem worse, the noice with the system being at a higher pressure than before now banged even louder. the plumber said change your TRV valves as they are cheap and nasty and causing the noice. i then bought a good make of them and sicne that day had no problem, just proves buy cheap buy twice! hope this helps any one else with the same problem!