Towel Radiator - loud knocking

[iddon]

Just installed a towell rad with TRV and it's started to "knock" and have to adjust TRV to rectify. Is this cuased by an air lock in the system? Have also bled rad and no air just water coming out. Any suggestions?

 

[rjm2k]

Did the instructions specify which side the flow had to be on relative to the bleed valve?

 

[iddon]

No, sales chap at B & Q said TRV was universal but I've been told that this isn't the case and need to switch the valve around opposite to the bleed valve at the top as it would appear not to be on the inlet flow into the rad. Does this sound right?

 

[rjm2k]

TRV may well be universal, but the rad may be designed to have flow and return on specific sides. One I just installed said flow had to be on opposite corner to the bleed valve.

 

[iddon]

Will re-fit TRV to opposite side and see how that go's
THx

 

[rjm2k]

It's not the TRV, if the radiator is designed to have the flow on one particular side and you don't have it that way you will need to switch the side the flow is on by either altering the pipework or turning the rad around. Moving the TRV from one side to another doesn't affect which side is flow and which is return.

Before you do anything I would check the radiator instructions to see if flow and return have to be on specific sides.

 

[iddon]

OK I think I understand, will take a look this evening and see which pipe gets warm first, TRV currently in off mode, to see which is currently providing inlet.