Is it easy/recommended/legal to powerflush my own system?

[stevenabell]

Hello All, I'll try to keep this brief.

I have a Baxi (Potterton HE) combi boiler, HW is fine, CH is not. The hot water for CH doesn't even make it past the elbow in the outgoing CH pipe - which at this stage is still even inside the boiler panel. Consequently the hot water running through the CH system takes its shortest route back to the boiler and the burner cuts out after about 1 minute, thinking that it has reached temperature. Of course it hasn't because the water isn't flowing through the entire radiator system.

Long story short, there seems to be a blockage in the pipe running from the boiler down to the heating manifold. Bearing in mind we've got underfloor heating (flat is barely 3 years old) so the point where the suspected blockage is, is physically higher than all the underfloor radiator pipework. A power flush was recommended and from what I've been reading, this can either be undertaken by a pro for anything up to 500/600 pounds, or, with a little bit of know-how, done by oneself using a product such as Fernox DS-40.

So, the questions are:
- Is this a relatively simple procedure?

- Is it legal to do it by oneself (I know this is a fascist state these days but I'd hope it would be)?

- Is it safe?

Potterton won't touch it because "the boiler is working fine". Go figure.

Sincere many thanks in advance for any info.

Steve

 

[gas4you]

Yes to all 3 questions

 

[stevenabell]

Cheers, Dave. So any info on how I might actually go about doing it?

TIA,
Steve

 

[cider]

3 years old and sealed system?
Cant see it needing powerflush.
May be a physical blockage.

 

[Agile]

Whilst dave thinks its an easy procedure i would not necessarily agree.

Firstly you seem to have an UFH system. In that case if its the traditional system then I would first be checking the thermal blending valve, pump and other equipment dedicated to the UHF system.

Secondly the choice of chemical to be used depends on the type of dirt to be treated and hopefully dissolved.

I would take the view that to be most effective considerable skill is required. We often read on here of boiler installers who just connect a pump without any chemicals and leave it pumping while they install the boiler. Not surprisingly the system is not always well cleaned.

Proper power flushing required a lot of running around to each radiator. I like to have someone else to help with the running around. ( OK then, I like to have a trainee to do all the running! They have got to learn somehow! )

Tony

 

[stevenabell]

Thanks for the continued comments guys. My impression from the gas engineer who attended is that the problem is a physical blockage - I'm estimating possibly a build-up of sediment in the elbow (we're in the south-east). The thing is, the flat is so warm that we only ever have the heating on maybe twice a year, so perhaps that's a contributing factor.

The more I think of it, a power flush was suggested by the insurance company, who I have absolutely no faith in whatsoever. Maybe a power flush isn't required then?

So if it's a physical blockage in the relatively short pipe which runs from the boiler to the UFH manifold, what's the best way forward?

TIA,
Steve

 

[Fluffster]

Very rarely will a power flush remove a physical blockage. You will need to cut out the section of pipe replace and then depending upon the result possibly add a chemical cleaner and final inhibitor.

Pete

 

[Tipper]

If your flat is only 3 years old then is it new build?

If so then isn't it covered by the NHBC 10year guarantee? Or at least some redress against the builder/heating installer.

If this isn't the case then how about flushing through with a bit of pressure from a garden hose or similar? If you know the make of the UF pipes talk to the manufacturer about maximum test/flushing pressures first.

 

[stevenabell]

The flat is at most 4 years old (a new build); and yes the NHBC 10 year guarantee is still in effect. However, (a) I'm not sure if this would cover a physical pipe blockage, and (b) to be quite honest we don't think their guarantee is worth the paper on which it's printed (prior experience). It's worth a quick call though so I'll try that so that I can tick the box.

Good point about the garden hose. One thing though - won't I have to drain at least part of the system before opening up the pipe? The point of the blockage is vertically located between the main cylinder and the UFH manifold. We suspect this because the pipe between the boiler and the elbow is hot, and after the elbow (i.e. going out to the UFH) the pipe is cold.

 

[Fluffster]

So where exactly are you going to move this blockage to if you get it to move at all with a mains flush?
Do it right and cut the affected pipe out.

Pete

 

[stevenabell]

Yep, NHBC aren't interested. No surprises there. From what I'm hearing the sure-fire way to get this is as Fluffster says - to cut it out.

Q: Since the affected pipe is above the UFH manifold but below the boiler tank, do I need to drain anything?

 

[Agile]

Most blockages on systems with iron components are magnetic.

They will respond by physical attraction to a powerful magnet.

Has that been tested?

Tony

 

[stevenabell]

Nice idea - this hasn't been tried and so I will attempt to source a strong magnet and do so. The pipe is copper (I'd say in the region of 15-20mm in diameter), and we're suspecting a build-up of sediment since we're in a hard water area. We'll give it a spin though.

Meanwhile if anyone could shed some light on my previous question relating to draining - that'd be most appreciated.

TIA,
Steve

 

[Paul Barker]

Easy is how customers describe the "little job" they want us to push ahead in the que is. I'll tell you the truth. Think and focus the whole time expend quite a bit of energy have ready all your experience for when something goes wrong as after all water can do a lot of damage, and learn on the job. You should get a 1/4 decent job done in a day or two.