Please help - how to connect flow & return pipe work correctly

[Marty1979]

Thanks for the vote of confidence!

 

[Ric2013]

Sounds like Marty basically knows his stuff. I'm not expecting an explosion.

 

[Marty1979]

Sounds like Marty basically knows his stuff. I'm not expecting an explosion.

Thanks Ric - much appreciated!

However, I need some assistance please. I've put a new radiator on the system and there is a very, very tiny leak on the joint between the TRV and the radiator tail (compression olive to join TRV). I have tried PTFE tape but it's very hard to get the wrap around when the tail with olive is wet. I was thinking of using Fernox LS-X on top of the PTFE? Any assistance would be great as I'm losing the will to live haha.

Seriously, thank you for any help!

 

[SavageW]

Is the tail of the rad fully inserted into the TRV? Try slackening the nut of the tail and tapping the side of the trv body so it slides more over the tail an then tighten. No point trying to put LSX or cover in PTFE only for it to mask the joint mate

 

[Ric2013]

Agreed. You should be able to get a seal between the rad tail and valve without any sealant and I wouldn't mix PTFE and LSX. (I'm assuming you can see some pipe on both sides of the olive and the olive's not right on the spigot?) If it leaks though, LSX around the olive (on the side nearest the valve (nut side doesn't need it and could get messy but won't do any harm) and reassemble should work. PTFE application is hard to explain and you really need to be shown 🙁

Don't panic, I became confident with solder long before I had any confidence in my compression joints 🙂 . I discovered (before I was a plumber) that slight leaks on compression usually fur up in hard water areas (not that I recommend this as a solution) and seal themselves 🙄

 

[Marty1979]

Thanks for your reply gents. Agree that normally you shouldn't need to ptfe or LSX the joint but I think some of these fittings are poorly machined sometimes. Just so we're clear, the leak was on the 'dead side' of the TRV - the tail with olive into the horizontal part of the TRV.

Also, I mentioned in here before that there is a bypass valve made up by a isolator screw type...shitty cheap thing. I want to get rid of the radiator in the kitchen that this thing is under all together but want to know if I can connect back into the return from the flow but connecting a 15mm auto bypass? Boiler is Valliant Ecotec.

Picture of existing pipe work attached. So I'm basically asking can I connect the flow pipe (bottom pipe with drain cock) to the one above (return) using elbow fittings and auto bypass?

Thanks ever so much folks.

 

[Ric2013]

So I'm basically asking can I connect the flow pipe (bottom pipe with drain cock) to the one above (return) using elbow fittings and auto bypass?

Provided that the pipework you are suggesting is always flowing when your central heating is on (i.e. you don't have a multiple heating zone system), I can't see why not. Some people say the bypass should be before the zone valves, but I can't see why you'd have insufficient flow through a cylinder coil, only likely to happen on a radiator circuit. No doubt someone will disagree?

 

[Ric2013]

If you have one of the new clever computerised pumps running on proportional pressure or Autoadapt, I'd fit a gate valve as a fixed bypass rather than an auto bypass though.

 

[Marty1979]

Thanks guys. It's a Valliant eco tec 23 combi boiler. If it has a integral bypass valve will that be ok? Other than that I could just leave all TRV on radiators on no 1 setting for example?

Thanks very much

 

[Ric2013]

TRVs on rads can shut down so that's why you need a bypass on all-TRV systems. If the boiler has its own bypass then that external bypass is confusing me. I'm wondering if it has a valid technical raison d'etre, or if it was installed in a misguided attempt to ?

 

[ShaunCorbs]

TRVs on rads can shut down so that's why you need a bypass on all-TRV systems. If the boiler has its own bypass then that external bypass is confusing me. I'm wondering if it has a valid technical raison d'etre, or if it was installed in a misguided attempt to ?

alot of internal bypass block very easily due to the small dia of the pass through

 

[Marty1979]

Ok guys. So if you were me would you be installing a auto bypass valve on the system even though there is an internal one? I'm not sure whether or not the isolater valve was there before the combi boiler was installed back in 2015.

 

[ShaunCorbs]

If you have all trvs yes I would install an external bypass always

 

[Marty1979]

Thanks for your input guys. Can I therefore ask from the pictures I've sent how I go about taking the radiator off of the wall and then add an auto bypass? Can I go from 15mm to 22mm (ABV is obviously 22mm) then back to 15mm? I'm just a little unsure whether or not I can just connect the flow to the return putting a ABV in between them as the radiator isn't serving any other rads along the way.

Please advise. Thank you.

 

[ShaunCorbs]

Any chance of a pic of the boiler ?

 

[Marty1979]

Any chance of a pic of the boiler ?

Thanks mate. I'm not at home but I can confirm that the boiler is a Valliant Ecotec 28 combi boiler. Do you you need a photo of the pipe work underneath or something?

Thanks again

 

[ShaunCorbs]

Thanks mate. I'm not at home but I can confirm that the boiler is a Valliant Ecotec 28 combi boiler. Do you you need a photo of the pipe work underneath or something?

Thanks again

That would be great

 

[Marty1979]

Thanks buddy I will do. Valliant technical dept said on the phone that their combi boilers don't need an additional AVB - I'm on their system boilers so not sure what to do! I basically wanted to cap off the flow and return and the radiator and pipes are not serving any other rads.

Will get a picture asap mate.

 

[Last Plumber]

Ok guys. So if you were me would you be installing a auto bypass valve on the system even though there is an internal one? I'm not sure whether or not the isolater valve was there before the combi boiler was installed back in 2015.

I thought we had discussed this ?

Is that drain tap in full socket?