Drayton TRV4 problems

[JonnyF]

Hi.

Having problems with these rad valves. The chrome type fitted to acova column radiators in a renovation project. Ex-plumber here but been out the game for 15 years.

Basically, they ‘work’ when heating starts from cold but then trv shuts off and never cuts back in. So for example - heating comes on at 6am (heating on for 2 hours and room stat set to 28*c to constantly call for heat) trv’s set to 3 or 4, radiators reach the trv temp after 20-50mins then they stuff off. After this, when the room temp drops after a further 30-90mins (e.g. 21* down to 18*) the valves never allow anymore heat into the radiators, even though the room is cool (confirmed via thermometer). Please don’t hold me to exact timings or temperatures but the trv’s definitely don’t kick back in. Only when they are manually turned up (4-max) does the radiator heat up, but then they shut off and never kick back in even though room needs more heat. They are effectively acting as manual valves not trv’s.

I have tried the special balancing key and although this restricts flow, once the valve shuts off it doesn’t kick in again. If I remove valve head the water flows constantly hot up flow pipe, through radiator and away down return pipe. Trv’s are fitted vertically.

I haven’t spoken to Drayton Technical yet as previous experience with ‘technical departments’ has rarely been truly helpful. Any help or ideas please?

Thanks

 

[ShaunCorbs]

Sounds like the heads are faulty / sticking time to get a new trv head

 

[JonnyF]

Sounds like the heads are faulty / sticking time to get a new trv head

Thanks. They are new - mostly bought from ebay at various times and by different sellers, but all in completely sealed packaging. I just can’t see how they all can be faulty....

 

[Chalked]

Hi
Your saying they heat up for 50 mins, then after a further 90mins they don’t come back on?
Your heating is only on for 2 hours so they won’t heat up, until there is call for heating. Your trvs can’t call for heat.

 

[JonnyF]

Hi
Your saying they heat up for 50 mins, then after a further 90mins they don’t come back on?
Your heating is only on for 2 hours so they won’t heat up, until there is call for heating. Your trvs can’t call for heat.

Hi. That was a rough estimation. The programmer is on and room stat is calling for heat as well. Even when one of the heads is removed (radiator permanently on) the other rooms that need more heat, the trv’s don’t sense that they need to open to let more heat into room via the rads.

 

[Gasmk1]

This is why I don't like TRV's they are not perfect setting on 3 or 4 is pretty low temp they rely on the air temp around them to activate at 3 or 4 the temp from the rad is probably enough to keep them shut. You have to experiment with which suits each room some like the lounge might need to be on full or near full whereas bedroom can be on lower