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

[Marty1979]

Morning folks.

So had some great answers how to drain down system but I would like to remove radiator fully and cap of the radiator so to speak. However, it's a two pipe system and the arrangement is in the photo provided for clarity.

Can I simply just connect the flow pipe back onto the return without causing issues to the system and the other rads? I think it's the last rad on the system as the drain cock is on the flow pipe in the kitchen and none of the others down stairs.

Thank you very much guys.

Martyn

 

[Last Plumber]

No, once you have removed the rad, replace the valves with compression stop ends.

 

[Last Plumber]

If fact, as long as it doesn't go through the wall to another rad, cut the pipes, stop end them and get rid of the mess.

 

[Marty1979]

If fact, as long as it doesn't go through the wall to another rad, cut the pipes, stop end them and get rid of the mess.

Thanks very much mate. Sorry as I probably sent the message in a rush. So basically the radiator that you can see is in the kitchen. The pipes feeding this rad are coming from the living room.

So am I correct in assuming that the kitchen radiator to be removed has a tee connection coming off flow and return in the living room?

There appears to be a by-pass pipe between the flow and return under the radiator as you can probably see from photos so there would not be a problem I'm assuming by connecting the flow back into the return unless I'm totally wrong?

Thanks again

 

[Last Plumber]

Thanks very much mate. Sorry as I probably sent the message in a rush. So basically the radiator that you can see is in the kitchen. The pipes feeding this rad are coming from the living room.

So am I correct in assuming that the kitchen radiator to be removed has a tee connection coming off flow and return in the living room?

There appears to be a by-pass pipe between the flow and return under the radiator as you can probably see from photos so there would not be a problem I'm assuming by connecting the flow back into the return unless I'm totally wrong?

Thanks again

You could although there is a potential problem.
If you connect Flow to return with an unrestricted 15mm pipe, it will rob flow from the rest of the Heating circuit.
It may cause an issue with other rads not getting hot enough.
You will also have a direct, low resistance circuit back to the Boiler (same as a fully open bypass). which is likely to bring the Boiler up to temp to quickly and knock it off, before the rest of the Heating is up to temp. Radiators are unrestricted of course but they have valves on each end which are used to restrict and alter flow rates though the radiators.

If you are permanently removing the rad, my advice is to lose the pipework with it.
If the system needs a by pass, I would install an automatic one in the correct place.
It may be that those pipes can be used for that purpose but you need to assess the size and type Heating system as well as how it has been installed.

 

[Marty1979]

Thanks very much and I hear what you're saying and makes complete sense about the boiler heating up and turning of the star etc . The pipe work what you can see is the original pipe work and the isolation valve has been given a quarter turn to probably restrict the resistance, yes?

The system has been converted (before we moved in) from pumped 2 pipe system to a Valiant combi boiler sealed system.

So to keep this basic in my mind, if I remove the radiator and cut the pipes back and cap them off individually this will be the best course of action so as not mess with the other rads, right?

Again, thank you very much for all your help!

You could although there is a potential problem.
If you connect Flow to return with an unrestricted 15mm pipe, it will rob flow from the rest of the Heating circuit.
It may cause an issue with other rads not getting hot enough.
You will also have a direct, low resistance circuit back to the Boiler (same as a fully open bypass). which is likely to bring the Boiler up to temp to quickly and knock it off, before the rest of the Heating is up to temp. Radiators are unrestricted of course but they have valves on each end which are used to restrict and alter flow rates though the radiators.

If you are permanently removing the rad, my advice is to lose the pipework with it.
If the system needs a by pass, I would install an automatic one in the correct place.
It may be that those pipes can be used for that purpose but you need to assess the size and type Heating system as well as how it has been installed.

 

[Last Plumber]

Thanks very much and I hear what you're saying and makes complete sense about the boiler heating up and turning of the star etc . The pipe work what you can see is the original pipe work and the isolation valve has been given a quarter turn to probably restrict the resistance, yes?

The system has been converted (before we moved in) from pumped 2 pipe system to a Valiant combi boiler sealed system.

So to keep this basic in my mind, if I remove the radiator and cut the pipes back and cap them off individually this will be the best course of action so as not mess with the other rads, right?

Again, thank you very much for all your help!

Yes you can cap them.
The only thing that I think needs attention is the Bypass.
Vaillant have a built in By-pass which is OK.
I would prefer a 22mm auto bypass in a loop of at least three meters. It should be before any Motorised valves (which you probably will not have) and between Flow and return.
A lot of installations rely on the By-pass in the Boiler. The only comment I have on Vaillant (ecotec range) is that they have a Thermal fuse in the top of the Heat exchanger which is designed to blow with overheating. If it does, that part is not available as a separate item as far as I am aware and it means a new Heat exchanger which is very expensive.
The chances are that the internal by-pass will suffice and nothing will happen. It is just belt and braces you understand and other Engineers may view things in a different way.

To make the job easier and taking into account the internal bypass, you could fit an auto bypass where the pipes in the kitchen are.

 

[Chalked]

Are you sure you have a two pipe system? That's piped up as a one pipe.
How old is your existing system /house.

 

[heliotrope]

That is a two pipe with bypass for pump.

 

[Last Plumber]

Are you sure you have a two pipe system? That's piped up as a one pipe.
How old is your existing system /house.

I can only think a knowledgeable individual as yourself, needs to squint a bit harder at the pic Chalked lol.
If that ball valve wasn't there I might have thought the same myself.

It is a mess i'll grant you that!

 

[Marty1979]

Yes you can cap them.
The only thing that I think needs attention is the Bypass.
Vaillant have a built in By-pass which is OK.
I would prefer a 22mm auto bypass in a loop of at least three meters. It should be before any Motorised valves (which you probably will not have) and between Flow and return.
A lot of installations rely on the By-pass in the Boiler. The only comment I have on Vaillant (ecotec range) is that they have a Thermal fuse in the top of the Heat exchanger which is designed to blow with overheating. If it does, that part is not available as a separate item as far as I am aware and it means a new Heat exchanger which is very expensive.
The chances are that the internal by-pass will suffice and nothing will happen. It is just belt and braces you understand and other Engineers may view things in a different way.

To make the job easier and taking into account the internal bypass, you could fit an auto bypass where the pipes in the kitchen are.

Thank you for your knowledge here - really appreciated. So basically there would be an inter

 

[Marty1979]

Thanks all for your input. If I install an auto bypass valve will I just have to make connection between the flow and return from 15 into 22mm? Was thinking of cutting those pipes back to inside the cupboard so they are hidden? Just protects the boiler and pump I guess even though there is one built into the boiler?

 

[Last Plumber]

Thanks all for your input. If I install an auto bypass valve will I just have to make connection between the flow and return from 15 into 22mm? Was thinking of cutting those pipes back to inside the cupboard so they are hidden? Just protects the boiler and pump I guess even though there is one built into the boiler?

You can use one of these. There are 15mm valves available but they tend to be a lot more expensive, don't ask!
The ones above or similar are available from most decent Plumbers merchants quite cheap.

 

[Last Plumber]

Chalked, has set the wheels of doubt off in my head.

Before you do the job in question, make sure it is not a one pipe system.

I looked at the age of the rad and the fact that there is a half shut ball valve in the pipe work and presumed it was a two pipe with a daft by-pass.

At first I was confident that Chalked had misinterpreted the photo but since then my mind has doubts.

It is possible that the system was piped as a one pipe and the rad has been changed since. It is also possible that someone in the past through lack of understanding, fitted that ball valve. I also cannot think why anyone would fit a by-pass there! although nothing surprises me.

I can see why Chalked thought as he did. This is one of the problems with forum subjects.

If we were visiting the property to look at the job, a scene like yours would cause me to look at other rads or pipe work, just to rule the possibility of a one pipe out.

You Should double check first. Look at other rads.
As the man said:-

How old is the house / system?

 

[Marty1979]

Chalked, has set the wheels of doubt off in my head.

Before you do the job in question, make sure it is not a one pipe system.

I looked at the age of the rad and the fact that there is a half shut ball valve in the pipe work and presumed it was a two pipe with a daft by-pass.

At first I was confident that Chalked had misinterpreted the photo but since then my mind has doubts.

It is possible that the system was piped as a one pipe and the rad has been changed since. It is also possible that someone in the past through lack of understanding, fitted that ball valve. I also cannot think why anyone would fit a by-pass there! although nothing surprises me.

I can see why Chalked thought as he did. This is one of the problems with forum subjects.

If we were visiting the property to look at the job, a scene like yours would cause me to look at other rads or pipe work, just to rule the possibility of a one pipe out.

You Should double check first. Look at other rads.
As the man said:-

How old is the house / system?

Hello guys. I'm putting a new radiator in upstairs and I can confirm under the floor boards is a two pipe system. The house is pre-war 1930's

 

[Last Plumber]

Hello guys. I'm putting a new radiator in upstairs and I can confirm under the floor boards is a two pipe system. The house is pre-war 1930's

Excellent, carry on!
I presume you know how to spot the difference!

 

[Marty1979]

Excellent, carry one!
I presume you know how to spot the difference!

When you say carry one? Yes, had some previous plumbing experience so I know what it looks like but obviously not time serves guys like you are. Thank you for checking with me though

 

[Last Plumber]

When you say carry one? Yes, had some previous plumbing experience so I know what it looks like but obviously not time serves guys like you are. Thank you for checking with me though

Carry On!

 

[Marty1979]

Carry On!

Morning folks. Just to say thank you for taking the time to help me out. Attempting the job today. Much appreciated.

 

[TMHM]

Anyone heard an explosion yet?

 

[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 ?