Powerflush question

[Mike13]

I have a 4-5 year old Vaillant that recently had its diverter valve changed, it became blocked up and would not heat properly after that.
I called a plumber who said it needed a powerflush, he did not do those but recommended someone who was not the cheapest, but an acceptable price and not too long a wait.
Poerfulsh was done, but I have misgivings about how well it was done, loads of flakes came out when I did a little test drain from the lowest point, and an outside line,some flakes ~5mm long, dead bit of pipe only about 15cm or so, and it was running out for about a minute and flakes kept coming.
The boiler is still regularly giving an F.24 and F.75, https://www.warmzilla.co.uk/blog/vaillant-boiler-error-codes-fault-codes-list says give it a powerflush if those happen. Do I insist on him coming back to do the job properly, as he is wanting payment urgently.
Since his clean I am also getting load bangs and knocking noises from the boiler.

What is the opinion of those who do this regularly.
He was a nice person, but there are four drain points that I know about in the loops and he only used one for the drain down part of the clean.
Am I being unreasonable?

 

[Harry Bloomfield]

Am I being unreasonable?

No, tell him to come back and do the job properly. It needs flushing from all the drain points, until it runs clear.

 

[Notch7]

I have a 4-5 year old Vaillant that recently had its diverter valve changed, it became blocked up and would not heat properly after that.
I called a plumber who said it needed a powerflush, he did not do those but recommended someone who was not the cheapest, but an acceptable price and not too long a wait.
Poerfulsh was done, but I have misgivings about how well it was done, loads of flakes came out when I did a little test drain from the lowest point, and an outside line,some flakes ~5mm long, dead bit of pipe only about 15cm or so, and it was running out for about a minute and flakes kept coming.
The boiler is still regularly giving an F.24 and F.75, https://www.warmzilla.co.uk/blog/vaillant-boiler-error-codes-fault-codes-list says give it a powerflush if those happen. Do I insist on him coming back to do the job properly, as he is wanting payment urgently.
Since his clean I am also getting load bangs and knocking noises from the boiler.

What is the opinion of those who do this regularly.
He was a nice person, but there are four drain points that I know about in the loops and he only used one for the drain down part of the clean.
Am I being unreasonable?

Where did he connect to do the powerflush?

Ive read it is best done at the pump, not at radiator tails

did he test the water at the end to check PH?

(warning: I’m an interested DIYer, not professional so could be talking bolox)

 

[Mike13]

He pumped into the boiler, but admitted to only draining from there. He is an old school plumber and made no mention of the ph, not sure he even knows what that means.

 

[Mike13]

The Plumber who powerflushed left it with about 1/2 of a bottle of ADEY MC5, presumably it is still carrying a part load of the acid/cleaner he used during the flush, there are 4 distinct branches off the main 22mm core distributing the water, and by his admission he did not drain each of those ends.
What are the recommendations to add while I wait for him to return?

Yes, it looks a mess, but because of where the access to pipes and where the rads suit each room it is actually sort of sensible, as well as being extended at various points. The drawing also concentrates on the connections between the radiators to help me balance it later.
Updated the diagram to better show the as fitted looping.

 

[oldbuffer]

1. If using a proper powerflush machine there is no need to use any drain points. The final few cycles are done through the machine, under power, with the pump flushing the water to drain. If there are any drain points on long dead legs of pipe, it would be sensible (but not essential) to open them briefly after flushing, then add inhibitor and top system up.
2. The error codes you mention reflect circulation problems. These need not be caused by a sludged up system, but could be other blockages or airlocks. Such circulation problems are also likely to cause noises in the boiler.
3. Mike13 makes a good point about pH testing. Both the pH of the water and the TDS (total dissolved solids) should be checked before and after a powerflush. Can't remember offhand as it a while since I did one, but I think they both need to come within 10% of the equivalent reading on the incoming cold mains. A lot of people don't do it, but it should be done.
4. How long did he take to do the powerflush? With 13 radiators I'd expect it to take around 8 hours. (1 hour to set up, 1/2 hour per radiator, 1/2 hour to test and clear away).
5. Did he suggest installing a magnetic filter on the return to the boiler? Unless you already have one. A magnetic filter would get rid of any traces of magnetite left after the powerflush.

 

[Notch7]

He is an old school plumber and made no mention of the ph, not sure he even knows what that means

I believe testing is mentioned on latest building regs - because it can show the level of iron oxide before and after - as old buffer explains

As I understand it, each all radiators are turned off at lock shield apart from one, then close that one, open the next etc.

the High flow rate of a powerflush machine should agitate all the legs of the system -and it should be done in both directions

the other thing is that powerflushing should be done with the boiler on so the water is hot as it circulates

 

[Mike13]

It already had an adey magnetic filter fitted when the boiler was installed. It took him about 8:30 to about 3 pm or so.
because of the layout it is hard to see if one of the multiple legs are blocked?
he fitted the additive by filling up the adey unit before turning the water on again.
I was extremely suspicious when loads of magnetite flakes came out of the drain when I let it run out over a quarry tile. I had about 2.5 bar at the boiler and the flow of water/silt was not that fast at the drain. The drain I used was at the radiator labelled "Dining Room W"(est). He cannot have run it properly to have significant silt about an hour after he left.
The noises I am now getting are definitely coming from the HEX, and it is occasionally very loud. Also I was feeling the pipe above the boiler pump while waiting to see how long it took to warm up again, and just a second after one of the bump noises the pipe was hot for a few seconds from the slug of boiling water pushed back the wrong way.
I have dropped the radiator set temp to 51C so as to try and stop it cavitating, and it is less but not gone.
Still had two F.24's and an F75 overnight.

That is about 3 cm of water from the system, it has had 1/2 bottle of MC5 added three days ago. Is that level of sludge acceptable?Some of those flakes are about 4 mm long

 

[oldbuffer]

1. Was the heating system not working at all after the diverter valve change?
2. What machine did he use to do the powerflush?
3. Perhaps as a first step you could get back to the powerflush operator, tell him the problems you are having, and persuade him to return and at least assess the situation. He / she really should have left you with a working system, unless it was not working when the flush was started and you were warned there was no guarantee the flush would cure the problem.
4. If he / she doesn't respond, you might warn them you are going to get the system water tested (Fernox offer a service for doing this) and his payment depends on the water quality being within acceptable limits.

 

[Mike13]

Well it was working but leaking and losing pressure before the change of the diverter valve.
After that it was limping into s.07 all the time and barely heating the house, but no bangs from the boiler.
After we now have bangs from the boiler, and he did come back and try running water through his pump and magnacleanse filer assembly, and he did show it running clear.
On the negative side his attempt to show me that the water was clear, he used an old yellow floppy bucket with loads of marks and stains on the base, absolutely impossible to really see if it was clean, that did not inspire me with confidence. It is possible that the blockage was never going to clear which is why I am asking before throwing toys out the pram!
He had a proper pump and reservoir that he connected into the magnaclean input and output, which is a plus, he said he flowed it both ways, another plus, he also seemed a nice person which helps.
he has come back and redone? or done the HEX, but the level of silt coming out within 2 hours of him leaving and he did not seem bothered does concern me.

 

[Harry Bloomfield]

he has come back and redone? or done the HEX, but the level of silt coming out within 2 hours of him leaving and he did not seem bothered does concern me.

It sounds as if he knew what he was doing, but on the other hand, the result seems to prove otherwise. My own system is 40+ years old, and I would be very concerned if that amount came out of it, or I had those type of issues.

 

[Mike13]

I am letting it settle and will pour off the liquid later so that I might be able to get an in focus picture of what has come out.
I guess I will start by stating my concerns at the amount of stuff still showing after his visit.
It is possible he did things in the wrong order to suit the crazy golf routing in the house and that may have let silt settle out somewhere unexpected?

That is from about 2 litres of fluid, biggest flake, near the top of the image is ~4mm long

 

[Mike13]

Is this normal?
I have had the drain to the outside open for about 50 mins, but water has still not got below the pump which is about 1.5 metres above the drain, so none of the downstairs rads are empty yet, and I cannot yet have a look at the condition of the pipes in and out of the diverter valve as water gushes out when I try, I do not remember it taking this long to drain down before. I have also now used the little red lever beside the pump, and some stuff comes out, I let the lever go and about 20 secs later I hear more water coming out when I use the draining lever.

 

[Harry Bloomfield]

For water to come out at maximum speed, the air has to be able to get in to replace it - have you made arrangements for air to get in somewhere high in the system?

 

[Mike13]

I found a hard problem, the diverter valve is missing the washer and circlip! I need to take them off the old one to get the heating back on this evening!
But still upset about how dirty the system still is after the flush.