Central heating and possible sludge issues

cooa99 · 22 Mar 2021

Hi all, I had a feel of a radiator behind one of the sofas and noticed that it was very hot at the top and Luke warm in the middle and bottom. I checked the other radiators and they were similar though no where as bad.

I am assuming this is built up sludge in the rads but no blockages to the pipes that I can see. My plan now is to isolate and remove the worst radiator and blast it with water to see how much sludge is in it.

I am a bit unsure of the next steps after that assuming I actually don't need a power flush.
I am a little bit confused about the sentinel products (i.e. X100, X200m X400). Which should I use and should I be thinking of a full flush of the system via the radiator drain points on the ground floor?

Also Should I be thinking of installing a Magnaclean filter even though we plan of changing the boiler in about a year as part of an extension?

Thanks

cross thread · 22 Mar 2021

Remove and wash a rad out will give you a idea of how dirty your system is

DP · 23 Mar 2021

More a case of incorrect distribution of system water. It is called balancing

cooa99 · 24 Mar 2021

Sorry for late reply.

So I removed the worst radiator and blasted it with the power washer. This seem to dislodge a lot of sludge that came out like black paint over the driveway. It took a while for it to clear out, though I doubt I got it all. The radiator was a lot better though. I may just about get one more radiator off so need a good solution to cleaning the whole system.

Should I do a full drain 1st to get rid of any sludge suspended in the system before trying to use one of the sentinel cleaners?

My hose has no exposed central heating pipework except for the the pipes going into the boiler from the ceiling above. Vertical height/clearance is only 24cm. The compact Magnaclean Atom Filter looks like my only option. A YouTube video also mentions that this unit has an adapter to use with power flushing machines yet I can't find one

JohnD · 24 Mar 2021

if you run X400 for a couple of weeks, it will help soften and loosen the sludge so that more of it comes out when you drain or squirt the radiators. This is a cheap and easy DIY job.

If you fit a magnetic system filter first, then not only will it trap some of the sludge that is loosened and flows round during the cleaning, it will also trap the particles that were loosened, but not removed, during your draining and squirting.

You will find a gratifying amount of sludge getting trapped.

At first, it is worth emptying the filter monthly. After a while the amount trapped will reduce and yearly will be enough. It is an easy DIY job.

If you're thinking of buying a new boiler, you want the system to be clean first so that old dirt is not pumped into it.

Your new boiler installation might include a powerflush and new filter, but it will do no harm to do your DIY clean now. The powerflush will be more effective at dislodging harder deposits.

Hugh Jaleak · 24 Mar 2021

X400 is the one you need initially, do not use X800, this is designed for use with Powerflushing machines and is quite aggressive. Not suitable to be left in the system. X400 can be left circulating for several weeks, when ready, drain down, and if you can allow fresh water to run through the system until it comes out clear, that will only help.

When ready, refill, vent and add a bottle of X100. This is the inhibitor that will prevent further corrosion hopefully.

cooa99 · 24 Mar 2021

Thanks all, X400 it is. I'll put that in for 2-3 weeks and drain off.

Is the X400 Rapid dose just as good as the X400 liquid?

Thanks

cooa99 · 27 Mar 2021

mmm ... looks like I have an issue.

Withe Central heating off I shut off the valve feeding the F&E tank and drained a decent amount of water from the system via the radiator on ground floor. The F&E tank was unbelievably filthy with deposits so I cleaned all that up. I then added the X400 to the tank. Opened the valve to fill up the header tank and went round the radiators bleeding them.

I then turned on the CH and could hear the pump churning away but boiler was just not firing up. Went round again re-bleeding the radiators and pump. There was also a bleed key looking vent in the airing cupboard just above the pipework coming/going into the hot water cylinder which I vented as well.

2 hrs later pump is still going but central heating is just not firing up!

Any clues please

cooa99 · 27 Mar 2021

I might have spoken too soon. I pressed the overheat thermostat under the boiler and it started working.

I noticed while draining the system that it was not that fast. I was hoping the water will come out fast like tap water. Is this normal or I have to also open all bleed valves around the horselike I would for draining radiators?

Thanks

JohnD · 28 Mar 2021

Yes, of course. Start upstairs and work your way down.

But you have just added X400 so don't drain it again for a few weeks.

Have you bought a system filter yet?

MeldrewsMate · 28 Mar 2021

Your slow filling/draining may be due to a partial blockage where the cold fill pipe meets the heating pipe proper; it's an area of low velocity so sludge can harden there and build-up. Test this by holding a magnet at the junction; if it sticks to the (non-magnetic) copper pipe then there will be a build-up of magnetic sludge (magnetite) within it.

As JohnD said, fit a magnetic filter to catch circulating magnetite, and give your next boiler a fighting chance.
Points to note: There must be a clear run of pipe from the boiler to the open vent pipe, ie no valves in that length. Be sure that the installation of the Magneclean does not unwittingly introduce valves.
I take it you have a Potterton Profile or Netaheat (?). A good boiler in its day, but too thirsty on gas nowadays.

MM

cooa99 · 8 Apr 2021

The x400 is in now for over a week, though wished I had used 2 bottles. The only exposed pipe work in the house is above the boiler and in the tight airing cupboard.
Regarding Magnaclean:
There is only a 22mm vertical height between the ceiling and the boiler (see pic). I doubt even the smallest filter will fit into that space. I am assuming its not possible to connect it as shown in the blue drawing.

Boiler Edited

cooa99
8 Apr 2021

Boiler in Kitchen

The airing cupboard is on the tight side so not sure it will be possible either

Airing1

cooa99
8 Apr 2021

Airing2

cooa99
8 Apr 2021

Also I did try the magnet trick and there was some magnetism in the airing cupboard on the pipes under the grey insulation. Strange because those pipes are very hot

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Central heating and possible sludge issues

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