Cleaning central heating system?

[Akshay]

Right, I've just had a new pressure sensor and pump fitted on a Vailant Ecotec combi boiler today. Luckily it was done under warranty but the engineer showed me (black iron oxide deposits) that the whole system needed cleaning and a Magna Clean fitted.

Bearing in mind this is the 2nd time both parts have been replaced in under 2 years, what kind of system clean do I need? He told me it costs approximately £600 to get a full system clean, doing each radiator at a time which kind of shocked me. Is there a cheaper type of clean that could achieve a similar result to prevent the sensor and pump getting clogged up again?

 

[Agile]

Power flushing is more often about £350 depending on the size of the system.

Usually chemical cleaning can produce similar results at less cost PROVIDING its done properly with the appropriate chemicals.

Taking each radiator off is a labour intensive method which is usually done by East Europeans who dont have the power flushing equipment.

Tony

 

[dcawkwell]

Power flushing is more often about £350 depending on the size of the system.

Usually chemical cleaning can produce similar results at less cost PROVIDING its done properly with the appropriate chemicals.

Taking each radiator off is a labour intensive method which is usually done by East Europeans who dont have the power flushing equipment.

Tony

Or me.
Flush it through with mains cold.

 

[JohnD]

If the problem is black iron oxide, then presumably the boiler was fitted badly on a dirty old system without cleaning it out, is that right? Or have you had a leak?

Do you know how to take the collected sludge out of the Magnaclean?

A Magnaclean is usually spectactularly good at catching black oxide, so if it was fitted prior to your recent problem, I'm surprised you got another clog.

It is always worth trying a chemical clean, especially if you have a Magnaclean and empty it frequently, before going to the expense of a powerflush.

Boiler maintenance companies often like to sell powerflushes as a good revenue earner (naming no names).

 

[Tibbot]

Flush it through with mains cold.

Cold water alone can't wash dirty hands, clothes, windows or cars, so how can anyone think it'll clean a CH system. The reason some in the trade think it does is because they see clean water from the drain point. That's because it shifts nothing and moves clean through the easiest path. Anyone who thinks different doesn't understand water movement.

 

[dcawkwell]

Flush it through with mains cold.

Cold water alone can't wash dirty hands, clothes, windows or cars, so how can anyone think it'll clean a CH system. The reason some in the trade think it does is because they see clean water from the drain point. That's because it shifts nothing and moves clean through the easiest path. Anyone who thinks different doesn't understand water movement.

So I suppose when I take a radiator off and flush it through with a hose pipe and see the black shooting out of the other end I am dreaming.

 

[Tibbot]

What you're shifting is the dirty water in the rad, not the settled dirt. When you've finished try re-filling, then shake the rad and see how much more you get out. It'll take many goes before it's clean. So not water alone, but water/physical movement.

Of course you can't shake the rads in situ. So if you think water is going to take convoluted diversions to clear dirt and not simply find the least resistance path to your drain off, then you must be dreaming.

 

[Akshay]

Thanks for the input guys, I am trying to avoid the powerflush route due to cost but do understand that it would be the best solution to shifting stubborn debris.

When the Vaillant engineer came round he showed my black iron oxide deposits inside the pressure sensor and also how the pump wheel wasn't moving freely.

I don't have a magnaclean fitted at the moment but that is my first priority job along with a system clean.

Once installed can I introduce more cleaning products like Fernox into the system via the Magnaclean, and if so how do I flush it out after the standard period to prevent corrosion? I understand I then need to introduce some Inhibitor like DS-40 into the system after that.

 

[GasBod]

Get a magnaclean or tf1 fitted and chuck a couple of bottles of this into system http://www.calmagltd.com/calchem

 

[JohnD]

DS40 is an acid cleaner, quite aggressive, so not something to leave in your system. it is liable to cause damage. For example the drain cock dripped on my jacket while I was using it
View media item 391
I am a competent amateur. If your main problem is black oxide, then fit a system filter, the sooner the better, and add a cleaning chemical. The Magnaclean is very effective, but tends to leak, usually after the guarantee has run out.

I have got a lot of dirt out of old systems using a Magnaclean in conjunction with X400 which is a mild, non-aggressive cleaner that you can leave in the system for weeks. It will not do any damage if you don't drain it out, although you should, because this will drain out loosened dirt. I use the Sentinel chemicals now, but Fernox are the other market leaders. I avoid other brands.

A system filter will continue to catch any remaining particles before they get the chance to form a new blockage.

The Sentinel and Fernox filters are both good, as well as a magnet, they have a "cyclonic" action like a Dyson which traps small particles even if they are not magnetic, for example limescale fragments.

These examples were from my Spiro filter, which I was very pleased with, but I understand is not so fast-acting. Note the reduction in dirt over the first three cycles.
View media item 3783

 

[CBF]

I'm surprised the engineer even fixed it when he found the sludge, most will just walk away