Cataract in expansion tank

[Calculus]

Thanks Steelmasons....and I've just found something else on the internet; one of the manifestations of the pump being set too fast is air build up in the radiators. Last week I noticed one of the downstairs radiators was tepid and when I bled it it was hissing air for about five minutes, so there was more air than water in it. If someone could look the photo of the pump above and comment on the speed the installer has set it to I would be grateful. I am not touching it without advice

 

[Steelmasons]

Air in radiators is due to open safety vent discharging water into F & E cistern..

 

[Calculus]

Is this safety vent some sort of tap or valve that's meant to be closed?

 

[Steelmasons]

Call someone..

 

[JohnD]

no, it's meant to be open so it can freely discharge if anythings's wrong.

try the pump on "med" and see if that helps.

Tomorrow, feel round your radiators to verify that they are all fully warm.

Have you looked for your magnet? You still need to clear the obstruction that (probably) exists. Can you do simple plumbing? If not, you need someone who can.

 

[Calculus]

JohnD this is looking positive! I turned the pump setting to medium and although there is still hot water draining into the expansion the rate is far less....not much more than a trickle...I'll keep an eye on it and find the magnet tomorrow...think I know where it is. Answer to your question is no, I can not do simple plumbing so will certainly get someone in if required.

 

[DP]

Had the system been installed correctly then pump speed won't be an issue...

Felt like saying that but could not be arrsed

 

[DP]

so will certainly get someone in if required.

If it is still pumping over, you need to get someone in

Pump speed is set to achieve acceptable circulation, not set to reduce pump over because there is an issue that has developed or plumbing is incorrect

 

[JohnD]

All the time it is pumping over, it is taking dissolved air into the system, which will cause your radiators to rust away (quite quickly) from the inside, so turning down the pump can only slow the damage a bit while you arrange a repair.

As it has not stopped the pumping over, you need to find that local plumber.

 

[Agile]

Turn the pump speed down more until it stops pumping over.

Then call someone!

Tony

 

[Calculus]

I've followed the advice of JohnD and others and done some investigations with a magnet. It seems to bear out the suspicion that there is a blockage in the system caused by iron deposits, which will require the services of a plumber. I'll describe what I did. I would be grateful if someone could read and confirm it does look like a blockage. It's a longish post but with pictures to relieve the tedium...

First, I put the heating on for an hour and felt the radiators. This was with the pump turned down to the medium setting. Even though the boiler is on maximum, radiators are warm (better than tepid) rather than hot; I am guessing this is the result of the lower pump setting. However, of the two main downstairs radiators one was barely even tepid. Neither of these radiators had any air in them.

Next, I nudged the pump speed down to a level where the pumping over ceased. This was just below the medium setting, as photo.

Then, the magnet.

I tested exposed copper piping leading to radiators; the magnet did not stick at all.

Then up into the loft where the water tank and expansion tank are. Again, the magnet did not stick to any pipes.

Next, the airing cupboard. Here, there were pipes where the magnet stuck. In the following photos I have used colour coded sticky tape:

Green tape: magnet didn't stick at all.
Yellow tape: magnet stuck but not strongly.
Red tape: magnet stuck strongly.

First, the top of the airing cupboard:

- all OK apart from that pipe on the left, which runs down to the pump (via a T-junction).

Next, the right hand side of the airing cupboard (ignore the left hand side of the photo): all OK here:

But looking at the left hand of the boiler, where the pump is, in the next two photos:

-there is lots of red and yellow tape, especially round the pump, also the pipe that goes into the bottom of the cylinder, and the piping around a box marked 'Honeywell Sundial diverter valve' that leads into the middle of the cylinder.

That's it. Looks to me like I have a number of separate blockages. Can someone please confirm

 

[Agile]

Yes, just as we suspected! When are you going to call someone?

But what do the bits of silver tape on the cylinder indicate?

 

[Calculus]

One more diagnostic photo:

 

[Calculus]

Yes, just as we suspected! When are you going to call someone?

But what do the bits of silver tape on the cylinder indicate?

When my son was a toddler he found a metal rod and discovered he could push it through the insulation and make nice holes

..and to answer your other question, I will phone tomorrow. Hopefully the winter rush hasn't started. This firm usually comes within a week or so.

 

[Calculus]

Before I contact the plumber there is one loose end I would like to tie up. In an earlier post I mentioned the diyplumber website suggested back pumping could be caused by the pump being installed the wrong way round, sending the water in the wrong direction. This pump was installed recently (August) by somebody working for the same firm I will be going back to. Now it's proved that turning the pump speed down stops the back pumping, can I assume the new pump was installed the right way round?