trv

[PEDANTICVINDICTIVEMAN]

If you unscrew where your arrow is pointing, you will be in the ****te, the valve head on that model is removed by unscrewing the "grey" ring above.

 

[ajrobb]

Read TRV4 Commissioning Guide

As I said, it is very rough and ready. The pump and the ABV have already been set. Just keep opening the lockshield a quarter turn at a time until the bottom of the radiator gets hot. Whether the temperature drop is exactly 11°C is not important for domestic heating as long as all the radiators get hot with the TRVs set to max. Once the TRVs kick in, any finer setting will be a waste of time and will work against variable zoned heating (i.e. people fiddling with TRVs for comfort and economy).

The main point I was trying to make is that keeping TRVs turned off for months is asking for trouble.

 

[jj4091]

Thanks for all the replies, it turned out the body was goosed as per the pics of a good one & the faulty one. Both are set to the fully open position.

I cannot get into it to narrow the problem down further, but I guess the pin has become detached from the bellows that I believe operate it.