Flush vs Power-flush

[cheradenine]

I am in the process of having the heating in a house we've just moved into updated, from a 1980s thing (inch pipes, header tanks, spaghetti junction pipes all over the house) to a simpler, modern combi.

I have reason to believe the system hadn't been treated well for a while (OAP previous owner) - there was a lot of black mess, and a few radiators were rusty on the outside, all the TRVs were ancient with limescale all over them. And a few of them were exciting Myson fan+heat exchanger units from out of the ark.

Because of that I'm replacing the majority of the radiators. Some will remain, but they're mostly ones installed much much later (mid 90s) with working TRVs.

So -- flushing. My current assumption is - given that I'm removing most of the likely source of sludge - is to not bother hiring a "powerflushing machine" and to use Fernox F3 in line with their instructions.

Make sense or anything else I ought to consider?

 

[JohnD]

A simple DIY chemical clean will do some good, especially if you add a system filter as well. It is easy and cheap.

I am a Sentinel user, so would put in X400, circulate it for four weeks, drain, rinse, refill, using X100 on final fill. If you fit a system filter, keep emptying it and you will be amazed and delighted to see how much gets trapped, long after you did the initial clean. As the amount of loose sediment gradually reduces, you can increase the interval between cleans from weekly to monthly to bi-monthly, and eventually to yearly, once there is no more than a smear of dirt in the filter when you empty it.

You can add X900 if you have a system filter, it does not need to be drained out and is supposed to loosen deposits so the filter can trap them. If you have limescale you can also add X200, which you also leave in, and it will gradually reduce them.

This way you will have removed quite a lot of dirt from your system, and greatly reduced the chance of a future blockage. It will not do such a thorough clean as a powerflush, and you might later decide to go down that route, especially if you are having a new boiler fitted.

I expect Fernox and others have comparable products.
http://www.sentinelprotects.com/uk/products/domestic/central-heating-systems

 

[cheradenine]

Ah. Thankyou for this - very informative.

I hadn't considered a filter. Given their cost is around that which I'd spend on powerflush machine hire anyway, it might be a better use of the money. I was a bit dubious previously, but I see they're now designed to capture non-magnetic grot too.

I wasn't committed to Fernox - I'd assumed they were a bit 'much of a muchness' / buy whatever happens to be on special ?

 

[simond]

Those Myson units will have copper fin heat exchangers and won't have contributed anything to the muck.

From the sound of it you are installing a combi yourself......a dirt filter is no substitute for proper preparation.

We have just finished a 26 rad install where only the pipework was carried over, all the rads skipped and the boiler cut up - and we got three full loads of muck out of a dual rod Magnacleanse/Powerflush.

That would have overwhelmed a standard dirt filter and wrecked a combi.

 

[Agile]

Make sense or anything else I ought to consider?

Yes, you should consider employing a gas registered person to fit the new boiler and to give you all the advice on your needs.

Those Myson units may look dated but technically they have a lot of advantages:-

Compact low water content heat exchanger.

Thermostatic control.

Rapid heat up of the room from cold.

If they were mine I might even consider keeping them and placing them inside one of the radiator covers with a little extra ducting to direct the air flow.

Tony

 

[cheradenine]

Heh - I thought the Myson's would be just to give you an idea of the vintage I'm dealing with - though I didn't know they still made them!

I'm not talking modern units; these are "60's look like an ugly gigantic radio, your choices being to either be warm or to hear yourself think". I actually think the idea in principle is pretty good, just these ones can't be easily hidden, are fugly and don't actually work terribly well any more.

I have someone registered who will come in and move the gas pipe and do the commissioning steps and tests (this is the second time we've done this, but the last house was somewhat more modern). Given that I could DIY powerflushing (I am in a DIY forum here, right? ) - technically pretty simple but labour intensive and dirty - I was trying to balance whether the hire & effort were worth it. The last time I searched about such things, system / magnetic filters' efficacy / desirability seemed to be a bit controversial. What I'm hearing is that they're probably a good idea in my case, that I'll still want to 'flush' (for an extended period, which is something I've learned), but I may go down the powerflush-machine route later as that's more of a judgement call. I might hose out one of the old rads and see how much comes out of it.

 

[JohnD]

if you are not changing the boiler yet, a filter and chemical clean will do quite a lot of good, and is cheap and easy. For X400, 4 weeks circulation is the optimum time. It is very mild and will not harm your system even if you leave it in for longer (but its cleaning power will diminish and the sediment will start to re-settle). There are faster and more aggressive chemicals where you have to complete the process in a matter of hours and wash all the chemical out.

However, if and when you do change the boiler, a proper powerflush beforehand would be sensible. The filter will then continue to trap new circulating particles (you can never get everything out).

 

[Agile]

A gas reg person is required to do many of the tasks on a new boiler fit. Not just the commissioning!

Fit mounting bracket.

Fit flue.

Install and test gas supply.

Commission boiler with gas analyser.

Complete benchmark.

Notify boiler install to Building control.

Tony

 

[cheradenine]

I'm not going to engage in a debate as to your interpretation of the gas regulations, and what you personally would or would not sign off on. I doubt that would be fruitful for either of us, as I imagine views are unlikely to change.

Suffice it to say that every engineer I've used (this will be our 4th example in total) has been entirely happy to do what I've asked, filled forms and notified BCO to that effect.

As a final word - thanks to those that replied. This has been most useful.

 

[JohnHarrison]

I'm not going to engage in a debate as to your interpretation of the gas regulations, and what you personally would or would not sign off on. I doubt that would be fruitful for either of us, as I imagine views are unlikely to change.

Suffice it to say that every engineer I've used (this will be our 4th example in total) has been entirely happy to do what I've asked, filled forms and notified BCO to that effect.

As a final word - thanks to those that replied. This has been most useful.

You are totally correct. Anyone can do the work as long as it is signed off by a guy with a Gassafe certificate.

You can add X900 if you have a system filter, it does not need to be drained out and is supposed to loosen deposits so the filter can trap them.

A proper magnetic a lose dirt filter with X900 sounds great deal with any boiler. As you said, a DIYer can keep cleaning the filter until it is clean.