Has my CH system been flushed correctly?

15 Jul 2016
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United Kingdom
I just had a new boiler installed and have a concern over the system flush that has been performed.
I had two radiators that were taken off the wall for damp treatment months ago. A few days ago, in preparation for the boiler installation, my husband has installed the wall brackets and we have put those back on the wall and connected by screwing on the nut that connects the radiator to the pipes. He has not touched any valves etc. I have told the boiler installer about this and requested that he checks that the radiators are connected properly. He has done the cold and hot flush according to the Installation certificate.
It was only towards the end of the whole installation when the heating was on, that I have noticed that the 2 radiators were still cold so I have pointed that out to the installer who then discovered that the lock shield valves were completely shut on them. It appears that they were closed when removed for plastering to avoid draining the whole system,as the people who took them off were plasterers not heating engineers and they did it the quick way. Also one radiator upstairs was set to 0 at the thermostatic valve. Does it matter at all what setting are the radiators set to when doing the flushing? Would the water reach the rads to flush out the sludge with lock shield or thermostatic valves closed? The installer has assured me that it doesn't matter and after he opened up the lock shield valves, a while later, the radiators became hot. I would like a second opinion please. Even though everything works fine,apart from the rads needing balancing, I have heard that the system flushing is very important for the health of the heating system and would like some reassurance. I am worried that the rads did not get the clean they should and the installer only said that it will be fine because he couldn't be bothered to do another system flush. He has also snapped one of the lock shield valve tops that enable turning it and insisted that it is not up to him to fix it as there was no reason for the valves to be closed in the first place.it was first thing I asked to check before they started!he managed to turn the valve enough to get the rad going but it obviously could be a problem in the future.
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To flush any rad, both valves must be open. The only other way is to take the rad off and flush it outside.
Anyone doing a rush should make sure all rads are opened.
Sounds like those two rads and there pipework have not been flushed. What type of flush and amount of time spent flushing will depend on your systems condition. Have they installed a system filter? are there cleaner and inhibitor stickers on the front of the boiler?
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Hi All!
Thank you for the responses! The radiators are all old without the fyns but have thermostatic valves.some are single and some double.we have been told that we could get smaller rads that would have the same output and be more efficient but the ones we have are not ancient either so stuck with what's there.I suspected that the flush has by passed the two rads that we have put on but then also the one that was set to cold on the thermostatic valve? That is 3 out of 6 rads in the house. I am not impressed!on the day I asked the guy how dirty was the water when he drained the system and he said that it was pretty clean..but that was after he discovered the closed valves so of course he is going to say that.on the other hand months ago when the rads were taken off the wall my husband said that the water wasn't very dirty.we have had a filter installed and the boiler is Worcester 25si. It was meant to be an investment for years to come so I am annoyed about the half job they have done with the flush that is meant to protect the system. According to the paperwork he has used 1l of cleansing agent and 1l of the inhibitor.i have not seen any stickers on the boiler though.is this something he should have put on? Do you think that I should get him back in to do a proper system flush again or hope that the filter will protect the boiler and trust that the system was reasonably clean in the first place?worcester customer services said that this will not cancel my guarantee unless a Worcester engineer decided that sludge was the reason of a breakdown in the future.as far as I know the guarantee does not cover for damage caused by scale or sludge anyway?so it would be good idea to prevent it as much as possible.
Thank you very much for responding to my questions- it was a nice surprise to log in and see them.the same question was ignored on another website.
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Ps.actually the installation certificate only states that the system has been cleaned in line with some British standard.i assume this is the cold and hot flush?it wasn't mentionedon his quote but I guess it would be done by default for a new boiler installation?
One of the processes to powerflush correctly is to close all rads and open each radiator in turn and vibrate the rad to ensure maximum cleaning is performed. balancing at the end should also be performed, obviously neither was performed.

How long did it take to powerflush? Around a working day should be how long it should roughly take depending on size of system.
Hi.the boiler installation took from around 8am to 4.30pm two people where there.to start with one guy can and let the water out of the system then started dismantling the old boiler.cant really tell how long it took him.the other guy went round the radiators to bleed them once the new boiler was on the wall.i certainly haven't seen them go round each radiator to manipulate the valves and flush individually as in such case it wouldn't be a surprise that the valves were shut on some of them. It looks like they haven't done the system flush properly at all...would you advise that I battle for them to come back?i have already questioned him on the day about it and he has already tried to wiggle out of it,assuring that the closed valves wouldn't have mattered.not to mention wanting to charge me to come back and replace a valve that he has snapped himself!i am tempted to give him a call,but then if the filter will protect the boiler and the system wasn't in a bad state to start with then maybe it's not worth the stress?
Ps.are different types of flushes?when installing a new boiler what basic steps should be taken?we have not paid extra for the flush. I am not sure what the manufacturers guidelines are and whether the required steps have been covered.i have read somewhere that a flush should be done by default as part of the installation.is that right?
It's really up to you Halschka, whether you are prepared to take them on or not. Going by what you have said, the flush was not performed properly. Will your boiler manufacturer warranty your boiler is the important question, they may but as you have found out it's up to their engineer.

A filter will help to protect the boiler, but it won't protect your rads that may rust out if there is corrosion left in the system. It's a difficult one to advise on as there are many variables. If a rad has a closed valve, it will not have been flushed, can't get much plainer than that. .

Only way to be really sure would be to haul the oldest rad off the system, take it outside and flush with a hose or better still a pressure washer whilst tapping with a rubber mallet and see how much, if any, corrosion is in there. You may get a little as a powerflush may not get everything but if it's bad and black then the job hasn't been done right. Were you advised to monitor the filter?

A valve they have broken if for them to fix, unless they advised you before that they had found a stuck valve that may break when they open it.
Thank you so much for your advice.we seem to have bad luck with tradesmen.i really wanted to find somebody I can establish a trusting relationship with and turn to them for any future jobs.its very disappointing that a guy who appeared trustworthy and professional does not want to take responsibility for his workers mistake (or negligence really).it is a local company, a small one.what come back do I have if he refuses to come back and put things right?is gas safe the body that I can raise a complaint with?hopefully it won't come to it!he has already lost himself a customer.we have a bathroom to replumb, mother in law and a colleague in need of a new boiler and I won't be recommending him!
Gas Safe will not be interested, that is my feeling based on personal experience.

You could take a sample of water from th system and get likes of Fernox to test it. Thy will tell you what system water quality is

For quality of work, talk to trying standards. Look at the Bnchmark logbook- has it been completed with figures obtained rather than copied from boiler spec

Sadly quality of work you got is not unusual.
Check the filter after a week or so of the heating being on with all radiator valves open , if no magnetite or very little (black sediment) within filter then don't worry about it and move on.
If the two radiators removed by plasterer were pretty clean then the rest will follow suit , not all systems require a chemical flush when installing a replacement boiler.
The installer may be right so give him some slack , had he charged for a chemical flush then fair enough but you say he didn't.
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Yes,I would rather avoid the confrontation to be honest. Is checking for cold spots a good way of establishing whether there is sludge at the bottom of the rads?it will take a while until we will be using the heating constantly for a week to do the test on the filter. I have put it on last night.it took about 45mins for all rads to get hot.unfortunately the one that matters most-in the lounge seems to be heating up last and it took it an age for the heat to spread-that is a double skin one.the one in the kitchen,single(one of the ones that didn't get flushed) heats all the way to the bottom after some time (mind you its nearly 3m long!!). I have hoped that the system would be left running like a dream.i only now find out what the radiator balancing is about and realising that we might need to do it ourselves as the professional obviously did not see it as part of the job.it is good to hear everyone's opinion.thanks a lot!
did you pay for a full on flush taking a day,or more likely you paid as little as possible and expect a rolls Royce job,now you looking for a way of not paying or demanding money off installer.All that flush system is a load of bolox in most systems anyway.just saying!

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