Rad vibrating - but how to reverse flow on this TRV? pic

[nickb99]

Our last, newly fitted rad vibrates loudly at a certain temperature point. Adjusting the trv a mm or two either way resolves it until the next time.

The forums suggest that the trv valve is set up on the wrong flow direction and reversing it will resolve the issue. So I took off the head but can't see any of the normal arrows. As these are Danfoss TRVs I checked on their site but the instruction guide seems to show a different style. Anyone out there familiar with these TRVs that can help? Pic;

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• nickb99
• 2 Jun 2013
• 1

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[newbuildinstaller]

there is two black arrows on the red bit and a line on the brass bit. simply turn the red bit by hand till the other arrow points at the mark on the brass

 

[newbuildinstaller]

http://heating.danfoss.com/PCMPDF/013R9355_RAS_C2_Keymark_VISXM302_.pdf

read here

 

[nickb99]

Appreciate the fast response but there are no arrows or markings. That is my problem. Thanks also for the pdf link but I did review that before posting.

At the 6 o'clock position on the brass ring next to the red ring there is a small cutout. This is currently aligned with the 'N' on the red dial. But no arrows, or anything at the 12 o'clock position, or anything else on the red ring that would suggest an alternative to the 'N'.

I could of course rotate the red ring one half turn. It happily turns both ways. If I did that the 4 or 5 on the scale would be aligned with the cutout. But then I would wonder why it should not be 6, or 3 etc?

UPDATE - after some more Googling I found out that these are called integrated presetting valves. Their datasheets don't mention anything about the ability to be reversed, just the dial moved http://heating.danfoss.com/PCMPDF/VDTVT102_IBV_013G3380.pdf. The N setting, factory default means its wide open. I will call the fitter tomorrow and ask for ideas, maybe they got the supply pipes mixed around for this rad.

 

[nickb99]

Just to close off this thread. This type of TRV valve is factory fitted and is not reversible. The Danfoss instructions are referring to different internals.
The heating engineer found that his mate had reversed the flow/return pipes during install of this rad and he had to correct them to resolve the problem.