Central heating problems

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Hi,

So I’m looking for a little advice/guidance please.
I have a F&E system which is dumping hot water into the F&E tank via the vent pipe.
I moved into the house 18months ago, last winter being my first in the house.
The downstairs rads were like warm while the upstairs were ok. Eventually the boiler stopped working. A engineered came round and changed the pump from an old grundfos to a grundfos alpha 2L 15-60 130.
That sorted the problem for a week or so, then the boiler stopped again.
Called out a different engineer, who diagnosed the problem as a blockage and said the Pump never needed changing. He unblocked the pipe (the one entering the bottom of F&E tank). He said the system was dirty and would need a flush at some point. (Not done yet)

Unblocking of the pipe sorted everything out for a good few months. The next problem I have is the F&E tank filling with hot water and sending it pouring out the overflow. It’s pouring in like a fully open tap.
When I disconnect the circulation pump supply, the pouring into the F&E tank stops.

Hoping that it is another blockage I have just filled the system with x400 cleaner but can’t pump it around the system as the pump needs to be disconnected.


Any advice on my issues?
I’ve checked the direction of the pump, it’s ok.
The actuator is in the mid position. All pipes before and after the pump are getting red hot.

Any advice would be much appreciated.

Cheers,
 
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Hi,

So I’m looking for a little advice/guidance please.
I have a F&E system which is dumping hot water into the F&E tank via the vent pipe.
I moved into the house 18months ago, last winter being my first in the house.
The downstairs rads were like warm while the upstairs were ok. Eventually the boiler stopped working. A engineered came round and changed the pump from an old grundfos to a grundfos alpha 2L 15-60 130.
That sorted the problem for a week or so, then the boiler stopped again.
Called out a different engineer, who diagnosed the problem as a blockage and said the Pump never needed changing. He unblocked the pipe (the one entering the bottom of F&E tank). He said the system was dirty and would need a flush at some point. (Not done yet)

Unblocking of the pipe sorted everything out for a good few months. The next problem I have is the F&E tank filling with hot water and sending it pouring out the overflow. It’s pouring in like a fully open tap.
When I disconnect the circulation pump supply, the pouring into the F&E tank stops.

Hoping that it is another blockage I have just filled the system with x400 cleaner but can’t pump it around the system as the pump needs to be disconnected.


Any advice on my issues?
I’ve checked the direction of the pump, it’s ok.
The actuator is in the mid position. All pipes before and after the pump are getting red hot.

Any advice would be much appreciated.

Cheers,
I had a problem of pump over from the vent pipe a few months ago. With the help of this forum, I reasoned that the only place a blockage would cause it is if it's between the open vent and cold feed connections. So I cleaned that bit out and it cured it.
But do mean water is coming out of the F/E tank overflow, not just from the open vent? That would mean there is water going into the water circuit somewhere. The only way I can think of how that might happen is if there is hole in the coil in the HW cylinder. But that's very unlikely, and if that was it you wouldn't expect it stop when the pump stops.
 
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.

Hoping that it is another blockage I have just filled the system with x400 cleaner but can’t pump it around the system as the pump needs to be disconnected.




,
Why does it need to be disconnected ?
 
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hi guys, thanks for helping.
Just to answer some replies.

I have tried all speeds, even the lowest causes the problem.
I’ve kept it on the lowest speed but have been wondering if it’s too slow and pressure is building up between boiler and circ pump, forcing water up the vent??

Although the vent is pouring quite heavily into the tank, it’s not filling up fast, after a few hours it will gush out the overflow for about 1-2 minutes (potentially scalding someone below)

I have put the pump on while the cleanser is in
 
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There’s the tank pouring.
The little black spot is the magnet. It’s sticks for about 6 inches (3 above, 3 below)

I take it that’s a blockage and most likely the cause?
 

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There’s the tank pouring.
The little black spot is the magnet. It’s sticks for about 6 inches (3 above, 3 below)

I take it that’s a blockage and most likely the cause?
The water level is below the overflow there. Not clear why it should rise to the overflow, unless it's thermal expansion, and refilling via the ball valve when the level falls on cooling. But at least it doesn't look like an inward leak. I don't much like the colour of the water!
I'd have expected restriction in the short piece of horizontal pipe to cause your symptoms. Maybe there's something there but not magnetic.
Any reason you've gone for X400, not the more aggressive X800? Is there a concern about causing leaks?
If the X400 doesn't cure it, you might consider removing things and rodding out physically. You could cut the three 22mm pipes and spring the pipes or trap horizontally to get it out. Good idea to refit using compression fittings for future maintenance, but you would need a bit of upward play in the 15mm cold feed, or disconnect at the F/E tank, to reassemble it. There will be plenty of upward play in the open vent.
 
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You have a blockage where the magnet sticks. Your plumber should of check with a magnet.

Need new plumber.

Andy
 
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I’ve drained the system, and rodded where the magnet was sticking. It was a little dirty.

Re filled the system ect and problem still remains.

As suggested above, I think it’s blocked in or next to the cylinder thingy
 
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Excellent, thank you.

I’m happy to get a pro out to replace it if need be, however is there a quick/temp fix I can do myself?
I assume this re work would reqiure soldering?
Don’t want to spend too much as
I’m planning a small extension with a new repositioned CH system for May 2019 (my boiler is 20 ish yr old).
 

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