Options for curing a blockage in Feed expansion pipe

[nairb999]

I have a Potterton Prima 60F Central Heating system. Had problems with air in the system and a suspected flow problem in Feed/expansion pipes( magnet is attracted to the copper pipe junctions).

Added Sentinol X400 3 weeks ago and the system ran a lot quieter with minimal air getting into the system.

Spent all day yesterday flushing system clean - the only area not cleaned was the heat exchanger - should this have been drained.

After filling the system up again and bleeding all the air out of the system it appears that all the original noises - kettling in the feed/expansion pipes are back.

The Feed expansion tank is also pretty murky which mystifies me after pumping so much clean water into the system.

Is my next step to cut out the suspected pipes and could I replace with plastic push pipes or is it better to replace with copper

 

[JohnD]

if you think you have a blockage or severe restriction, cut out the Tee (if that's where it is) and renew in copper. If you use compression joints it will not be so neat but will be easy to re-open if it blocks again (it is also difficult to solder a good joint on wet pipes).

When you were cleaning and flushing, did you bale out the F&E first; did you turn up the pump and open one rad at a time to squirt it through?

It is no good just opening the drain and letting water flow in from the F&E, as it will mostly just flow down the single easiest and shortest route.

Cleaning never gets 100% of the grime out.

If you had much black sediment and can afford the extra £100, fitting a Magnaclean on a 22mm vertical Return will give you a great feeling of satisfaction as it collects circulating black sediment and continues doing so for months to come. You can add more X400 if you want (you need inhibitor too) as it works for a month or so and does no harm if you leave it in for longer (but it is not an inhibitor). As far as I can see it is only worth doing this if you fit a Magnaclean to trap the sedment that it loosens, otherwise it wil eventually settle again.

I believe Merseyside is soft water so I presume not much limescale?

X400 is a good mild cleaner that loosens the black sediment nicely, you can get more aggresive ones but i have not used them. I am just a housholder.

 

[nairb999]

if you think you have a blockage or severe restriction, cut out the Tee (if that's where it is) and renew in copper. If you use compression joints it will not be so neat but will be easy to re-open if it blocks again (it is also difficult to solder a good joint on wet pipes).

I would prefer to use copper compression joints - not to worried about cosmetics. Could I remove old soldered T and re-use the pipe - will it clean?

When you were cleaning and flushing, did you bale out the F&E first; did you turn up the pump and open one rad at a time to squirt it through?

I didn't bale out the F&E first - that would have made sense

it is no good just opening the drain and letting water flow in from the F&E, as it will mostly just flow down the single easiest and shortest route

I opened the drain on each downstairs radiator individually - draining and then reverse flushing

 

[JohnD]

If you cut out the old Tee, I wouldn't bother trying to re-use it - just make up a new bit. But you can if you really want to. Scrape out all the old black from inside, or it will be dislodged and float round in the water until it collects into another blockage, or possibly damages your pump (another advantage of a Magnaclean!)

If there is still any mud in the F&E, bale it out now and scrub it clean.

As you will have gathered, I am keen on the Magnaclean (do a Search) and was delighted at how much loose black sediment it collected, even after cleaning and flushing.

But there may be a more skilled person who can advise on use of a more powerful cleaner if you think there is still a problem inside the boiler (they are often not circulated through the radiators as too aggresssive)

 

[nairb999]

If you cut out the old Tee, I wouldn't bother trying to re-use it - just make up a new bit. But you can if you really want to. Scrape out all the old black from inside, or it will be dislodged and float round in the water until it collects into another blockage, or possibly damages your pump (another advantage of a Magnaclean!)

Rather than cut into pipe I was hoping to heat up the t connection and remove the pipework. Replace 15mm feed pipe with 22mm - replace leg to pump 2ft. Other pipe which is only 4" long, I was hoping to scrape out and leave in place. Does that sound like a good plan?

 

[JohnD]

a closed pipe which has had water in it is almost impossible to dry completely. the remaining steam and water droplets make it very difficult to cleanly melt the solder. But you can have a go if you like. Try not to let the heat damage any nearby joints.

 

[gas4you]

Drain some more water out of the system and whilst doing so look in the f&e tank. If it is filling as you drain, you haven't got a blockage in the feed pipe.

 

[nairb999]

Drain some more water out of the system and whilst doing so look in the f&e tank. If it is filling as you drain, you haven't got a blockage in the feed pipe

I am pretty confident that it is draining becuase when I was draining the system I did not prop up the ballcock and the system was emptying quicker than it could fill.

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