Powerflush

Another response to Norman. "A question must also be asked about the effectiveness of your system circulation pump. Is it rotating? ( you can buy a wee rotating magnet for testing in a plumbers store)."
The pump was replaced fairly recently under contract so I'm confident it's working. We've also had a new diverted valve and pcb for the boiler recently.
I suspect that gunge has accumulated during the summer when the heating was off and is lying in the pipework somewhere.
 
reeac said:
I do wonder, when reading such stories, what kind of inhibitor (if any) was in the system. Our 19 year old system has, so far, shown no evidence of blocking up or sticking TRVs and very little need for radiator bleeding. It's efficiency was originally stated to be about 85 percent and it continues to show that when serviced so I'll keep it until it goes severely wrong.
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+1... Apart from year 1, I haven't had to bleed a radiator. My heating engineer's advice was you need to get rid of all the iron based sludge, as it can generate gas, hence the need to bleed regularly.
 
reeac said:
I do wonder, when reading such stories, what kind of inhibitor (if any) was in the system. Our 19 year old system has, so far, shown no evidence of blocking up or sticking TRVs and very little need for radiator bleeding. It's efficiency was originally stated to be about 85 percent and it continues to show that when serviced so I'll keep it until it goes severely wrong.
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We have been here for ten years and put in inhibitor when we arrived but what happened in the 30 odd years beforehand will remain unknown.

From another standpoint I do not like the engineers making rather hamfisted attempts at trying to sell us 'extras' that we amy or may not need when they turn up for an annual service....but that is the way of the modern world
 
As LW395 said the crud and grunge that circulates is enough to block the very fine capilaries in the heat exchanger and completely block them or can cause hot spots which shut down the boiler, so a power flush has to be done when a new boiler is put in, if it is not the boiler manufacturer will not honour their warranty. We had a client with a commercial building who had 3 boilers run side by side and the guys that installed them put in a strainer but hadnt flushed the system as they should have, i was on site when the heating went down had a quick look, found a blocked strainer crud had gone through and stuffed up 3 boilers, warranty claim refused, 3 new boilers and install courtesy of contractor who then flushed it all.
 
Update. Plumber came yesterday and put some flushing fluid in. He's coming to power flush next Wednesday but he's proposing to connect his pump to the kitchen rad, I thought it had to be done from the boiler or pump - does it matter?
 
That's OK the pump can connect either via the 22 mm connections with pump removed or via 15 mm supply/return legs (radiator connections). The key thing is the flow rate achieved and most flushing pumps will achieve 90 to 150 litres per min.

Here are a couple of links which may be helpful to you.
Powerflushing

http://www.powerflushassociation.com/Top_10_power_flushing_tips_misconceptions.html

https://www.hss.com/hire/p/central-heating-flusher ( You can hire for £100 per weekend) but shows a pic of it connected to radiator connections.

Hopefully your chap knows what he is doing, that he has put the correct amount of pre treatment chemicals in (my concern is that this may not get circulated until the flushing pump comes on line) and that your circulating pump is running now and 'circulating'. The key to effective flushing will be good flushing flow rate, chemical softening and getting the water temp up to about 85 deg C.

I would recommend that you ask your plumber to fit a '' Magnaclean' unit on the boiler return line (after flush is complete) and show you how to operate and clean it. Once your system is operational clean the magnaclean once a month until you establish how 'dirty' the flushed system is. Once happy system clean all you need to do is to top up with inhibitor once a year ( you can do this via the magnaclean unit) and clean the magnaclean.

I would be interested to learn how long he actually flushes for and if he gets your system running satisfactorily.
 
ghostlymoron said:
When we replaced our old boiler with a modern condensing Worcester Bosch we cut gas consumption by 30% which is about £300 pa. We could have a new boiler every 3 years for that. But we've had this one 11 years so I figure I'm ahead of the game.
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Quote to replace my boiler was £2,500 plus VAT! Gas and Electric currently cost £165 per month about half of which is for the gas boiler hence my 12 year estimate if I was to cut consumption by 25%. I have system with separate pumps for central heating and water heating and it works faultlessly.
 
It's well worth fitting a new boiler, if for no other reason that you have a good clean out of the whole system - the amount of muck one gets out is phenomenal.

GM lives a few miles from me and I bought a new boiler and had it fitted to a 12 radiator system 2 years ago for about 130% of the price he's quoting for a powerflush.
The boiler is not a Worcester Bosch but it's Sedbergh A rated and has a 10-year warranty on the burner.
It appears, on modern boilers, that it's not the burner that goes first - it's the electronics that pack in. In my case after 7 years, the PCB replacements were potentially as expensive as a new boiler.
Perhaps a call before Tuesday (when the new boiler has its 1st service) may be of considerable cost benefit to Ghostlymoron.
 
The problem with our system is not the boiler anymore but the fact that the pipework is clogged up with sludge completely preventing circulation to some parts of the system. As long as the maintenance agreement is in place, any replacement of parts is free. The price for the new boiler installation was much more than yours, Charles, I think but replacement like for like should only be relatively simple and cheap if the boiler connections are in the same place. (Last time the boiler was repositioned, flue installed, radiator added and extensive pipework mods done by Mullins of Shrewsbury) Some things like the compulsory power flush were not included last time although the system was drained and filled a couple of times.
BTW, I've read good reviews of Valliant boilers and would consider one in future.
charles_reed said:
It's well worth fitting a new boiler, if for no other reason that you have a good clean out of the whole system - the amount of muck one gets out is phenomenal.

GM lives a few miles from me and I bought a new boiler and had it fitted to a 12 radiator system 2 years ago for about 130% of the price he's quoting for a powerflush.
The boiler is not a Worcester Bosch but it's Sedbergh A rated and has a 10-year warranty on the burner.
It appears, on modern boilers, that it's not the burner that goes first - it's the electronics that pack in. In my case after 7 years, the PCB replacements were potentially as expensive as a new boiler.
Perhaps a call before Tuesday (when the new boiler has its 1st service) may be of considerable cost benefit to Ghostlymoron.
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I have been helping a mate with his system.
Firstly it's a combi, and hence more complex, the diverter valve is more subtle and more prone to clogging with crud.
The system has had more chemicals through it than a 60s rock star.
The crud we've had out of it is terrifying. The magnetic filter has certainly earned its keep.
With hindsight, a powerflush would have been the right thig to do from the word go, but we might still have ended up taking it to bits to free up the diverter valve.
The problem with just using chemicals and going through circulate, drain, rinse, fill cycles is that it takes a lot of time compared to pumping stuff around and filtering it via a powerflush. We've spent over £60 on chemicals, including £5 worth of citric acid and about £5 worth of phosphoric acid, which substituted for (another) bottle of Sentinel descaler at £18 a go. The cost of water we've put through it is not small either, as he's on a meter in SW Water territory.
The OP's system could be blocked at every rad, or it could be the diverter valve not switching over, or the heat exchanger or some other bottleneck. It takes a lot of crud to block a radiator totally, a serious amount to block them all. Much less to block the common bottlenecks perhaps? A fraction of a teaspoonful in the wrong place will leave some boilers stuck in HW only.

The problem is, if there really is zero circulation, you can't get chemicals to circulate. A powerflush will force the issue.
But if the outcome is you end up wanting a new boiler next year, you will be stung for powerflushing again, as it's obligatory for building regs and the boiler warranty. Even a new build has to be signed off as properly rinsed AFAIK?
Even in London you can get a flush for under £400, then you'd be mad not to add £100 or so for a mag filter IMHO.

Then again there may be some underlying problem e.g. a leak causing chalk bearing water to be constantly added.

You could hire the kit and DIY?
 
Re the cost.
I have worked for a number of companies that do reactive maintenance to local authorities over the years.
The current typical rate for a powerflush on a 3 bed house is £ 126-50 -£135-00& the typical contractor pays his subcontractor 15% less. Centrica have actually done it for that rate on some contracts I have been involved in
That includes driving to the job for a "one off" etc plus all the usual overheads of a large company plus the long wait for payment etc
Just shows how individual householders get ripped off !!
 
I agree that if there is a total blockage somewhere the chemicals will not penetrate it as the flush will take the line of least resistance and effectively by pass the blockage. In this respect a single pipe system would be better, but, in all other respects, a double pipe system is superior and that is what I've got.
Fingers very crossed for Wednesday's procedure.
 
NormanB said:
First off your system would benefit from cleaning. The problem is finding anyone who would do it properly. Many will turn up with a big pump, connect it and achieve not very much. A question must also be asked about the effectiveness of your system circulation pump. Is it rotating? ( you can buy a wee rotating magnet for testing in a plumbers store).

I am surprised that your heat exchanger has failed so soon and I am sure Worcester would not expect their boilers to fail in that timescale UNLESS the water chemistry was neglected. Your maintenance contract has not really delivered for you in that regard.

Of course it depends on how handy you are but it is not too difficult to achieve an improvement yourself.
This assumes you have a functioning pump ( replace if not proven).
1. Drain system fully.
2. Remove all radiators and flush using garden hose.
3. Replace radiators but isolate at both sides.
4. Fill system with a system cleaner and vent.
5. Circulate hot in accordance with instructions.
6. Dump the lot.
7. Dose with Fernox inhibitor, refill and open up radiators and vent.
8. Put system in use.

If you had an average side house you could do this in a full working day.
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We did this a couple of years ago, took out all radiators, closed of all valves, bar one which we connected to the garden hose and back flushed - good pressure. This obviously fills up the header tanks and overflows down the overflow. Make sure you don't overfill. Flush and drain a couple of times - have the other pipe fitting on that Radiator fitted with a drain pipe (standard hose lock tap connectors work)
Before refilling fit a filter system such as this
http://www.screwfix.com/p/fernox-tf...g_Jd_GbVRORZ1IZbmIZW5v0k51XLc_5iNoaAnJD8P8HAQ
It will keep you system clean.

Flush radiators manually outside - refit

Worked brilliantly.

25 rads done in a day. You need someone to help getting them off - finger at each end. I used to drain them out of the nearest window to avoid an accident carrying down stairs!

You could add a cleaner a day before, but I found that mostly the drudge had settled to the ground floor pipes.
 
Yeah that's a good way of doing it.
I would though, have bunged the expansion tank pipe (plumbers merchants sell those conical bungs).
A small plastic dustbin around 5 gallon (like for home brew et al) is useful for tipping the contents of the radiator into - before carrying the radiator outside. I used to tip the debris down the 'designated' loo ( then is only one loo to clean afterwards). Remember to empty the dustbin after each radiator otherwise gets too heavy and leads to accidents.

Yes you are right most of the sludge seems to gravitate to the ground floor radiators and pipework.
 
The only advantage of using a p/flushing pump is that you can flush the cleaning chemical still hot backwards and forward through the system. I prefer to dose the system with cleaner and use it as normal for a few days then depending on access to your boiler disconnect the flow and return at boiler fit a hose pipe to one and a drain hose to the other and flush with mains water doing each rad individually by turning of the other rads then reverse the pipes and start again. If you have a complete blockage the chemical may or may not have cleared it and if the mains flush doesn't clear it you will have to cut into the pipework to find and rectify the problem. Definitely fit a mag filter on the heating return ( they still impress me even after years of fitting them)
PS Magnaclean filters work very well, I liked the look of the Spirotech but was not impressed with it in use.
Pete
 
Daydream believer said:
Re the cost.
I have worked for a number of companies that do reactive maintenance to local authorities over the years.
The current typical rate for a powerflush on a 3 bed house is £ 126-50 -£135-00& the typical contractor pays his subcontractor 15% less. Centrica have actually done it for that rate on some contracts I have been involved in
That includes driving to the job for a "one off" etc plus all the usual overheads of a large company plus the long wait for payment etc
Just shows how individual householders get ripped off !!
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Normally councils manage to get themselves ripped off..
£135 + VAT seems very reasonable to me.
If it does the job.
The person who was saying £300 in the office said it was several hours work more than half a day IIRC, for a 'man and a boy'. Maybe a lot of the LA jobs are not so dirty in the first place so there is less work to get them adequately clean? Maybe the contractors price the basic job low to get in the door, then any further work needed is more profitable?

Whatever, under £400 looks like thr going rate, BG looks like a rip off.
 
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Chris_Robb said:
.... Flush and drain a couple of times - have the other pipe fitting on that Radiator fitted with a drain pipe (standard hose lock tap connectors work)......s.
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But you may need an extra rubber washer in it. As I found out the messy way!
Also a good weapon was a long washing machine hose, which enabled flushing water in to the bottom of the mag filter. There was only room for a right angle fitting not a hozelock type.
 
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