New Radiator Tails Rust looking Discolouration

techweb · Oct 11, 2022

Hi,

I had a new radiator fitted around a month back and I've noticed the joints which are sealed with Hemp (or modern equivalent / Boss White appear to be slightly discoloured / rusty. This might simply be a little seepage before the joint sealed etc as there is not weeping from the joint that I can see / feel. Is this normal / expected? Might seem paranoid, but I'd rather get something resolved now rather than have a rusty radiator several months down the line.

I'm surprised Hemp (or modern equivalent) / Boss White is used these days but many folks seem to swear by it.

Thanks...

ShaunCorbs · Oct 11, 2022

Loctite 55

Did you notice anything at the time of install ?

techweb · Oct 11, 2022

ShaunCorbs said:
Loctite 55

Did you notice anything at the time of install ?

I didn't to be honest... nothing seemingly leaking now.

ShaunCorbs · Oct 11, 2022

I would keep an eye on it for the next month even if it’s putting a kitchen towel below the joints

techweb · Oct 11, 2022

ShaunCorbs said:
I would keep an eye on it for the next month even if it’s putting a kitchen towel below the joints

I fully intend to but thanks for calling out. Is it common for this to happen prior to a seal? Like some expansion / curing takes place? I'd personally have thought PTFE would have been used opposed to 55 and boss white.

Chuck · Oct 11, 2022

techweb said:
I'd personally have thought PTFE would have been used opposed to 55 and boss white.

It occurs to me that perhaps the radiator had slightly oversized threads and/or the connectors were undersized and ptfe wasn't sealing. (If you use a good quality brand of radiator, e.g. Stelrad, the chances of this sort of problem are very low IME.)

Another possibility is that the installer had to dismantle the joints for some reason and transferred some rust from the threads onto the hemp in the process.

techweb · Oct 11, 2022

Chuck said:
It occurs to me that perhaps the radiator had slightly oversized threads and/or the connectors were undersized and ptfe wasn't sealing. (If you use a good quality brand of radiator, e.g. Stelrad, the chances of this sort of problem are very low IME.)

Another possibility is that the installer had to dismantle the joints for some reason and transferred some rust from the threads onto the hemp in the process.

They are Henrad which is a type / brand of Stelrad. They came from a reputable merchants. But of course may be simply the plumbers choice

When radiator was replaced so was TRV and lockshield.

ShaunCorbs · Oct 11, 2022

techweb said:
I fully intend to but thanks for calling out. Is it common for this to happen prior to a seal? Like some expansion / curing takes place? I'd personally have thought PTFE would have been used opposed to 55 and boss white.

It could have been on first heat up when everything is new etc

techweb · Oct 11, 2022

ShaunCorbs said:
It could have been on first heat up when everything is new etc

Funny you say that actually... after the rad was replaced the heating was not run for a few days after as the boiler was also faulty. The system was pressurized and it was done by freezing pipes.

Is heat part of the curing process?

New Radiator Tails Rust looking Discolouration

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