Symbols on TRV Valve

[RJH]

Just noticed one of the TRVs leaking - from the pin. Tried various thumps, twists and tightenings, but it's still weeping a little. In my spares box I've got a number of TRVs that I've 'improved' over the years, but they have different markings and part numbers.

They both have arrows in both directions, so bidirectional I'd guess. But they have different part numbers (that resist google), are marked 'GB', and different symbols. One looks like a comb (radiator?), and one looks like an inverted 'U':

Are they the same thing? They were fitted at the same time by a plumber who, when fitting a new boiler, uprated the valves to comply with regs.

I'm going to try a quick swap without draining the system down - just emptying the radiator and taking out as much pressure as I can. Wish me luck :-)

[Matthias Czech]

Am 14.03.2021 um 12:34 schrieb RJH:

For the 'comb':

[RJH]

Ah, thanks. Looking at the other one more closely, it's not 2 people about to hug in a pre-Covid sort of way?!

[Matthias Czech]

Am 14.03.2021 um 14:36 schrieb RJH: [TRV] ..

Dunno. Never seen that symbol.

BTW: The stamps look very similar to the ones on this valve:

Zoom in!

[John Rumm]

Look pretty similar from here. Both obviously TRVs, which is a good start!

You need to dump the pressure from the pipework as well - only normally takes a few litres to do that (depending on the size of the expansion vessel).

I normally find pushing the body of the valve against the pipework[1] while you get the lock nut fully undone helps control any leakage, then you can whip it off fast and get a thumb over the end of the pipe (or swap directly to the new one).

[1] If the rad tail comes up through a suspended floor there is always the chance it will drop down when no longer supported by the connection to the rad - that can introduce an extra element of "complexity" to the process of a live swap. So I normally clamp my vice grip spanner on the pipe at floor level so that it can't move down.

[Robert]

A WET (& DRY) Vacuum cleaner can do wonders in capturing any escaping water.

[RJH]

It's the bit just below the letters GB.

Remarkably painless. Took the pressure out, after isolating the boiler and rads, using the bleed screw. Went to a dribble after about 10 minutes, maybe 2 pints.

Ah, you say that now :-) Although it wasn't that bad, considering this is GF, with 2 floors above. Maybe 1/2 a pint.

Good idea - although this was 10mm looped behind the skirting, so relatively easy to get everything lined up. Less than an hour to do, fingers crossed, heating's on, no leaks so far.

Yes - I see (on youtube) a lot of the trades people use them. But really, there wasn't much water, and it was all caught using the paint roller tray.