Central heating boiling.

[phillips900]

I have a problem with my central heating system. It's a vented system y plan with a 3 way valve. The boiler is a ferrol sigma 60 and danfoss controls. 3 bed house pump speed on number 2

The main problem is that every couple of days at 7:30 in the morning (when the time clock shuts the system down) I get a massive rush through the pipe work and rather a lot of banging, followed by a trickle of water. The
trickle of water is water flowing from
the overflow pipe. The boiler temp is
only set to around half way so i don't
think it's boiling over. The heating
stops at 7 and the dhw is left on till
half 7. I think the 3port valve is failing
as when the dhw only is selected the
upstairs rads get hot. Could this 3port
valve issue be causing the air ingres
problem or is it more likely too be 2
separate faults? It just seems really odd that I only get this problem in the morning.

Cheers

 

[Armo74]

The system could be pumping over.
The valve could be stuck in mid-position,
There may be a blockage in the cold feed pipe.

 

[phillips900]

The system seems to be filling ok when I bleed the system after one of these "incidents" so i don't think there is a blockage. The manual override arm on the 3 way valve does move.

How would I know if it's over pumping. Could the switch in the 3 way valve keeping the boiler on after the pump has switched off?

 

[Armo74]

If you are having to constantly bleed your rads the cold feed is probably blocked where it tee's into the flow pipe from the boiler.
See FAQ's for testing methods.

 

[Gas2Air]

The system seems to be filling ok when I bleed the system after one of these "incidents" so i don't think there is a blockage. The manual override arm on the 3 way valve does move.

How would I know if it's over pumping. Could the switch in the 3 way valve keeping the boiler on after the pump has switched off?

This is what annoys me. OP asks, gets advice then thinks the advice is wrong. How is it filling ok on bleeding? It will be partially blocked air sep or open vent/cold feed config.

 

[phillips900]

The system seems to be filling ok when I bleed the system after one of these "incidents" so i don't think there is a blockage. The manual override arm on the 3 way valve does move.

How would I know if it's over pumping. Could the switch in the 3 way valve keeping the boiler on after the pump has switched off?

This is what annoys me. OP asks, gets advice then thinks the advice is wrong. How is it filling ok on bleeding? It will be partially blocked air sep or open vent/cold feed config.

Sorry I didn't mean to cause any offence. I'm just trying to get my head around things. How can i tell if the pipe is blocked? I've just tried to stick a magnet to the feed pipe to the system and it sticks. It also sticks on both pipes after the 3 port valve.

 

[Armo74]

Try and post a pic of the pipework and highlight where it sticks if you can.
Basically the blockage is a build up of magnetite which is magnetic.
The problem pipework will have to be cut out and re-piped.

 

[phillips900]

The magnet pretty much sticks to all the heating pipe work in the airing cupboard. Sorry for the pictures but it's quite tight in our airing cupboard.



Could I try draining a couple litres from the system and see if it refills to confirm a blockage? Or could a partial blockage be causing my problems?

Cheers

 

[Armo74]

The first pic showing a 15mm pipe and a 22mm pipe look like the cold feed and vent pipe the 15mm being the cold feed.
If the magnet sticks in that area I would say that's pretty much as good a confirmation as you are going to get.

 

[phillips900]

Right I've tried it with a stronger magnet now ( was only using the magnet clasp on my phone case) and it will literally pull the magnet from my hand. How does the magnetite get into the system? Are the magnetic filters any good for after I've got the pipe work replaced?

 

[Gas2Air]

It doesn't get in the system. It is formed by water/air/metal reacting. The cold feed is a zone it will block. Yes a filter will be an advantage, but it maybe that it isn't piped correctly.

 

[phillips900]

What could not be plumbed correctly about it. The system has been been there since the house was built in the 80s. Would problems with the way the system was plumbed not have been apparent before now?

 

[Gas2Air]

What could not be plumbed correctly about it. The system has been been there since the house was built in the 80s. Would problems with the way the system was plumbed not have been apparent before now?

No. It will take time. Are you defunct in the facts of our advice?

 

[phillips900]

What could not be plumbed correctly about it. The system has been been there since the house was built in the 80s. Would problems with the way the system was plumbed not have been apparent before now?

No. It will take time. Are you defunct in the facts of our advice?

I was simply asking a question. I would have thought the system would have been fitted by plumbers so was stuggling to see how they could have plumbed it wrong.

 

[Gas2Air]

What could not be plumbed correctly about it. The system has been been there since the house was built in the 80s. Would problems with the way the system was plumbed not have been apparent before now?

No. It will take time. Are you defunct in the facts of our advice?

I was simply asking a question. I would have thought the system would have been fitted by plumbers so was stuggling to see how they could have plumbed it wrong.

Indeed. The soldering looks pro.