pipe from airing cupboard capped off in loft

[flutterbye]

Hi

Firstly thanks again for help in previous posts. This board is really great for folk like me.

Our CH system is I think a fairly standard S plan system with FE tank in the loft and HW, 2 MVs in the airing cupboard below. The FE has a 22m expansion pipe which rises up over the FE tank and a 15mm feed coming from the bottom of the tank.

Whilst clearing out the loft I noticed that the 15feed from the bottom of the FE tank went down to the loft floor and then had been cut. One part of the cut had been capped off, and the second was joined to the 22m expansion pipe. I'm guessing the reason for this was some time in the past a blockage where the original 15mm feed meets a 28mm pipe down in the airing cupboard.

Two questions arise for me:
1/ The pipe that starts in the airing cupboard from a 28mm pipe, now rises up to the top of the airing cupboard and along the loft before being capped. I've had a lot of problems with air in the system. Purging air out after draining down takes hours and even weeks later the pump doesn't run consistently quietly. Could this long, dead pipe be a cause?

2/ Is it ok to connect the 15mm feed to the 22m as described above? Perhaps I should investigate whether there really is a blockage, clear it and restore the pipework to the original (independent 15mm feed plus 22m expansion).

Thanks again in advance for any suggestions.

 

[flutterbye]

Sorry if these are stupid questions but can anyone help?

 

[45yearsagasman]

They are not stupid questions. I would investigate as to why the cold feed was joined to the vent pipe. Your suspicions may be correct in that it is blocked lower down, possibly where it connects to the system pipework.
This section will need cutting out and cleaning or at worse replacing if it cannot be cleared. Reconnect the cold feed to the original configuration, add some inhibitor and away you go. If you boiler has overheat protection then you may consider this arrangement. No air will be drawn into the system via the vent. View media item 29821

 

[Phill Peck]

I would think you suspicions are correct about a previous blockage it has been done like this for ease but is not ideal and will not help with the air the best thing to do us drain down and locate the blockage, remove and then re-pipe

 

[Nige F]

Hi

Firstly thanks again for help in previous posts. This board is really great for folk like me.

1/ The pipe that starts in the airing cupboard from a 28mm pipe, now rises up to the top of the airing cupboard and along the loft before being capped. I've had a lot of problems with air in the system. Purging air out after draining down takes hours and even weeks later the pump doesn't run consistently quietly. Could this long, dead pipe be a cause?

Thanks again in advance for any suggestions.

28 pipe in airing cup. suggests a converted gravity primaries circuit to cylinder

 

[misterdubya]

OP, not all boilers are suitable for a combined c/f o/v.

Do you have the make and model of your boiler, and does it have an overheat stat?

 

[flutterbye]

Many thanks for the replies. I've investigated further and found that the magnet sticks to the pipe just _below_ the tee. In the picture the tee referred to is just above where the magnet is and the 15mm pipe comes in from the loft just above that. It would seem like the 28mm pipe below the tee has some kind of crap in it because the magnet sticks to the pipe but it can't be completely blocked because I think that is the return from the radiators. There are about 15 rads which maybe explains the large pipe I don't know.

Anyway, presumably there isn't a blockage that would stop water entering the tee from the 15mm pipe above it because the tee doesn't react at all to the magnet? But if its reacting so much to the pipe below it I presume I should try to clean it there? I'm just a bit afraid of cutting through the 28mm because I don't know if I could put it all back together again!

Some further info is that I had had 2 bottles of x400 in the system for a month prior to this. Now I drained it down again and filled with 2 bottles of x100. I wonder if maybe there previously was a blockage where the 15mm meets the tee but that 1 month of x400 dislodged it to further below?

In any case, cracking open that 28mm tee scares me a bit. I wonder if I could open up the 15mm and just poke something down there to clean it up?

Also, would there be any harm opening slighly the capped off 15mm pipe in the loft to release air and then close it again (at least before I get around next spring to removing the blockage and then resoring the pipework to its original layout as advised?

Untitled

• flutterbye
• 4 Nov 2011
• 1

Untitled

• flutterbye
• 4 Nov 2011
• 1

 

[Nige F]

In any case, cracking open that 28mm tee scares me a bit. I wonder if I could open up the 15mm and just poke something down there to clean it up?

Also, would there be any harm opening slighly the capped off 15mm pipe in the loft to release air and then close it again (at least before I get around next spring to removing the blockage and then resoring the pipework to its original layout as advised?
]

Both exellent ideas you could re join the cut 15 above the 28 with a simple compression coupling

 

[flutterbye]

Thanks but any idea how I can clean out the 28mm pipe from the 15mm opening that is about a foot (or more?) higher up?

I guess any sludge I do remove would go further into the pipework?