Repair Danfoss TRVs

[emergencyman]

There is a big building with about 30 rads. Its the top floor TRVs that are playing up and sticking. I`ve got most going for now but need to change 14 of them.

Its old steel pipe, so on this job I would rather attempt to repair TRVs than drain down and replace.

They are old Danfoss TRVs, the head is held on by an allen key.

Is it possible to just change the internal parts without a drain down?

Thanks

 

[JCplumb]

Not sure to be honest mate, I've seen some that look like they dis-assemble, but never tried to.
Why not replace them? It will be more costly for the customer = more profit for you, but they will be getting new and probably lnoger lasting TRVs.
In my experience, when you try to cut corners to reduce the cost of a job, you usually end up taking a lot longer and get called back more.
I've got a TRV in my house that sticks every year, I pull the pin up and stick as much WD40 on it as I think it will take and it sorts it out for that winter, next winter I'm doing the same again... One year I will actually replace the little bugger...

 

[stevetheplumber]

ive never heard of trvs that can be stripped down just drain and replace them sounds like a nice days work to me

 

[zeebeedee]

Watch the pins on them! One flew out on me the other week on a similar sounding system!

 

[hammers4spanner]

Drain down and replace if i was you gotta be worth a decent amount of wedge idf its on iron think of the ££££££'sss

 

[emergencyman]

Thanks for the replies. I know what you are saying is right about doing things on the cheap always comes back to bite you, but I`m sure that I once read about a kit for a TRV from one of the big brands. As I remember it was new insides that screwed into the body ( a bit like a tap conversion kit) and I might be correct in saying that it didn`t require a drain down ( a bit like a supatap - I`m showing my age now).

I know replacing TRVs will earn a few quid, but on this occasion I`m shying away for 2 reasons.
1. It has old rusty steel pipework and can see it falling to bits.
2. They are pleading poverty, so perhaps best to earn a few quid for changing internals than nothing if drain down, replace TRVs and repipe if required quote scares them off.

But, looks like drain down it is. Not sure that I will get 14 done in a day though :wink:

 

[stevetheplumber]

you may be getting confused with the conventional valves where the spindle comes out to allow new o rings to be fitted
think it was hattersley or was it peglers

 

[GrahamM]

Thanks for the replies. I know what you are saying is right about doing things on the cheap always comes back to bite you, but I`m sure that I once read about a kit for a TRV from one of the big brands. As I remember it was new insides that screwed into the body ( a bit like a tap conversion kit) and I might be correct in saying that it didn`t require a drain down ( a bit like a supatap - I`m showing my age now).

I know replacing TRVs will earn a few quid, but on this occasion I`m shying away for 2 reasons.
1. It has old rusty steel pipework and can see it falling to bits.
2. They are pleading poverty, so perhaps best to earn a few quid for changing internals than nothing if drain down, replace TRVs and repipe if required quote scares them off.

But, looks like drain down it is. Not sure that I will get 14 done in a day though :wink:

Some of the danfoss brands have a replaceable gland seal/valve insert, but a draindown is still required
http://heating.danfoss.com/PCMPDF/Valve-inserts_VIGWD102.pdf

 

[Roger Welton]

Honeywell do a too for replacing the cartriges on their trv's probably what you're thinking about.

 

[Dannypipe]

Yeah, there used to be a tool for servicing certain makes of TRV's. I'm not sure which ones, as I've never done it.

14 in a day. With the system drained, over two an hour is achievable for most of us. Then a bit of markup on the chemicals to re-dose the system..nice days work. Put something in your quote to cover yourself incase of air locks when re-filling. Or am I teaching you how to suck eggs!!?

 

[Leo21]

Daft though it seems, why don't you contact te manufacturers. They'll know.