Sludge in Central Heating System

[Onetap]

Surprisingly from the responses I have received here, they have ALL suggested that I replace with a close system, i.e. combi boiler.

A sealed system is NOT the same as a combi boiler.

You need to locate the writing on the outside of some of the grey plastic pipe; this will identify the make and whether it is barrier or non-barrier tube. The rate of corrosion suggests that it is more likely a leak or else it is pumping over during some of the heating season,i.e it may only pump over when the CH only is on and the TRVs have mostly shut themselvesd.

 

[namsag]

Agile would you care to make sense of your comment.

 

[RedHP]

All,

Many thanks for you comments so far.

Happyplumber - The make of my current boiler is Ideal, but I couldn't tell you the model just yet (I'm at work), and it was installed when the house was built in 2000.

Alfredo - The pump is on speedy 2 (of 3). This has also been replaced by a plumber who said that my old pump wasn't sufficient.

Vulcan - Another plumber noticed that I didn't have an expansion pipe, and suggetsed that this could be the issue. However, after consulting some of his colleagues they decided that this wasn't the issue and suggested a closed system.
The feed tank is in the loft and the pump is in the airing cupboard, about 3/4 meters below it. The boilder is in the garage, which is below the airing cupboard, so all these components are almost directly below one another.

Sorry Onetap, my mistake. The have all suggested that I have a closed system.

Red

 

[Agile]

I usually manage to solve these problems by converting to a single pipe F&E thus retaining an OV system.

 

[mahogany]

I am not a plumber but I have had probs with frequently venting one rad. I have checked many of the things suggested and I was suspicious that there was pumping over.

I rigged up a small jam jar suspended inside the feed/expansion tank and positioned below the vent pipe so that any pump over would go into the jar and then overflow from there harmlessly into the expansion tank.

I was rather disappointed when I inspected the jar several times over the next weeks and found it was empty. Bu**er - must be something else. Still looking.

You might like to try this little test - its a diy jobby

 

[Agile]

A sludge producing problem can be caused by sucking air down the expansion pipe!

Putting a little water in the jamjar to visualise that does not always help as any air in the system will cause significant pressure surges whenever the pump is started.

Tony

 

[namsag]

Hope you check the MI when converting to commoncold feed open vent Agile as it is not acceptable on a lot of boilers

 

[vulcancontinental]

All,


Happyplumber - The make of my current boiler is Ideal, but I couldn't tell you the model just yet (I'm at work), and it was installed when the house was built in 2000.


Vulcan - Another plumber noticed that I didn't have an expansion pipe, and suggetsed that this could be the issue. However, after consulting some of his colleagues they decided that this wasn't the issue and suggested a closed system.
The feed tank is in the loft and the pump is in the airing cupboard, about 3/4 meters below it. The boilder is in the garage, which is below the airing cupboard, so all these components are almost directly below one another.



Red

On many current Ideals the manufacturer doesn't allow a combined cold feed and vent (one pipe arrangement) but they do have a low head configuration that stops most problems. However we don't know the model of boiler.

If you really have 9-12' of head above properly configured cold feed - open vent pipework I'd start to look elsewhere for the problem. Unless I'm reading this incorrectly.