Boiler problems

[Fordy81]

Had major problem with my boiler but a gas engineer found that something or other was blocked solid with 'sediment' as my system had been off for about 4 months (renovation).

However now, when putting the heating on, the boiler fires up then cuts out again a few minutes later, before firing up and repeating, despite the temperature not being raised to that requested by the thermostat.

This also happens with the hot water. The boiler will keep running if I run the hot top, but if I leave it off it will turn off within a few minutes despite no hot water. On one occasion the sequences of the lights showed overheating.

Any idea what could be going on? It's a Potterton Suprima, 4 years old, hot water tank upstairs, small tank in the loft etc.

 

[Dan Robinson]

Stuck/guffed pump probably.

 

[Gasescape]

Choked cold feed maybe ...

 

[Fordy81]

Stuck/guffed pump probably.

Thanks Dan.

I should add I've had a new thermistor put in if that eliminates anything.

The rads do get hot and it does get up temperature but it's taken an hour to get from 21 to 24 degrees.

 

[Fordy81]

Choked cold feed maybe ...

Sorry but what does that mean?

Anything to do with the F&E tank?

 

[Gasescape]

Choked cold feed maybe ...

Sorry but what does that mean?

Anything to do with the F&E tank?[/quot

Yip , the feed pipe from the f&e tank may be blocked ..

 

[Fordy81]

Yip , the feed pipe from the f&e tank may be blocked ..

Ok. And that pipe goes straight to the boiler does it? I think I may have turned the red valve stopcock thingy. I wonder if it's not full open. Could that cause the problem?

If not, how do I go about unblocking it? Is there something I can do to test if it's blocked?

 

[ALCPlumbing]

Overheating is usually caused by circulation problems most likely caused by a weak or seized pump, or a blockage somewhere. You could try adding some cleaning chemicals and draining down after this has circulated (or tried to) for a week or two. This would be the cheapest job that you could do yourself before paying an engineer. You may have to bite the bullet and get someone in but definitely worth a go.

 

[Gasescape]

You could try & drain the system & see if the f&e fills ,if it doesn't sure looks like a choked cold feed ( however not being on site it could be anything )

Once had a dude leave a bung in the f&e tank

 

[Fordy81]

You could try & drain the system & see if the f&e fills ,if it doesn't sure looks like a choked cold feed ( however not being on site it could be anything )

Once had a dude leave a bung in the f&e tank

Ok, drained the system, both with the F&E on and off. When on it refills no problem. Water was/is a little murky, but not like when I first drained it in February, that was solid black.

Gonna wait for it all to drain down and clean the tank out. Then will add some inhibitor and run the CH for a bit until I melt. How long ideally should I have it running for? :/

Also, the pump makes a bit of a humming/buzzing noise. Or at least it was last night, even after the hot water had been turned off. Is this normal?

 

[Fordy81]

Overheating is usually caused by circulation problems most likely caused by a weak or seized pump, or a blockage somewhere. You could try adding some cleaning chemicals and draining down after this has circulated (or tried to) for a week or two. This would be the cheapest job that you could do yourself before paying an engineer. You may have to bite the bullet and get someone in but definitely worth a go.

My money is probably on another blockage then. Had one before, just above the pump. Can only describe it as a 'junction'. Two 22m pipes coming down from the loft (one is overflow or something and goes into the F&E) and then one from out of the floor, I think from the boiler. These 3 meet at what I can only desbribe as a small tin can, before it goes down to the pump. This tin can was absolutely solid of sediment. I'm guessing I could have this built up somewhere else, but perhaps not quite as bad as water and rads do eventually warm up.

 

[Fordy81]

One more thing.

I have a Wilo 50 pump. I'm running the central heating and it's too hot to touch. I think I read somewhere this could indicate a knackered pump?

Also, it's fitted 'upside down', in so much the label is upside down. Is this an issue at all?

 

[Fordy81]

I thought some pics might help.

This is the 'tin can' that was blocked.

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• Fordy81
• 21 Jun 2014
• 2

The whole pipe work.

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• Fordy81
• 21 Jun 2014
• 2

The pump.

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• Fordy81
• 21 Jun 2014
• 1

And this is the back of the pump. That arrow points downwards.

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• Fordy81
• 21 Jun 2014
• 1

 

[Fordy81]

Bump.

 

[dreadnoughtheating]

Do I read that the 'Canister' (actually an Air Separator or Aerjec) is/was definitely blocked?

You could try placing a magnet on it, (a fridge type will do, not one of those 'Tom&Jerry ACME cartoon types), if it is attracted to it, and copper is NOT a magnetic material, it would indicate that a lot of magnetite - goggle it - has solidified in the canister, causing a circulation issue.

If so, cutting it out/re-piping is the only realistic option, and, you may well still need a replacement pump if the motor is burning out/impellor housing is also sludged up.

DH