How clean should CH be after flushing?

[shd1970]

Hi all

So I have had MC3 in my central heating for 10 days and today I have emptied the system

I have filled the system twice bleeding the radiators also and ran the system each time for 45 minutes before emptying again immediately after turning the central heating off

I have also left the hoses on my lowest drain points individually while the filling loop was open to give it a further flush

I have now drained once again, and as you can see from the attached photo, the water still appears yellow

Can anybody clarify just how clean I should be expecting the water to be please or should I continue with the above approach until it is virtually clear?

TIA

 

[Mottie]

Can anybody clarify just how clean I should be expecting the water to be

Should be as clean as it goes in.

 

[shd1970]

Should be as clean as it goes in.

Thanks @Mottie and that’s the answer I was expecting although I’m a tad puzzled as to why it’s taking so many attempts to run clean

I’ve filled and bled the strain and plan to run the heating for a few hours tonight, and then a quick hour run tomorrow before emptying again

 

[Mottie]

I think if you leave drain points open while filling the system, the water will take the easiest route out and not go round the system. When I did mine, I took each rad off, took it in the garden, drained it, filled it with a hose, shook it, drained it, and kept repeating until they ran clear. When they were all back on, I then filled and drained the system until it ran clear and only then did I give it a final fill with some inhibitor.

 

[endecotp]

Can anybody clarify just how clean I should be expecting the water to be please

What do the instructions that came with the cleaner say?

 

[DP]

You will never empty the system by opening the drain tap
Each ‘drain’ and fill dilutes the residual in the system.

One way to achieve what you are attempting is to run the boiler at low temperature, balance the draining and filling so that pressure remains steady and then leave one radiator open to system while others are closed to circulation
When water clear, open the valve on next radiator and close the one 5hat has been flushed

Heat mixes the water in the radiator being flushed. Cold flush ( like power flush) only clears the bottom rib on the radiator

 

[shd1970]

I think if you leave drain points open while filling the system, the water will take the easiest route out and not go round the system. When I did mine, I took each rad off, took it in the garden, drained it, filled it with a hose, shook it, drained it, and kept repeating until they ran clear. When they were all back on, I then filled and drained the system until it ran clear and only then did I give it a final fill with some inhibitor.

Yeh understand that @Mottie which is why I did each of the 4 rads individually
Fyi I have 4 upstairs rads and 4 downstairs and all the downstairs have drains
I know the water will take the shortest route and thus the upstairs rads won’t get clean water when I flush them individually but I’ve refilled the whole system 3 times now so it must be nearly clear, surely

It’s not a complicated system by any stretch so as I say, I’m hoping tomorrow drain looks virtually clear

I did contact Adey tech support and they said their products are compatible so a little cleaner left in isn’t a problem however I’m going to persevere and drain a few more times

I think what is surprising me still is that the cleaner is only a 500 mL bottle and I checked out the size of all my radiators which totals 30 litres but obviously that would be plus pipework also
So if I said 5 L to fill all the pipework that would mean the cleaner only accounts for a 75th of the systems fluid

 

[shd1970]

You will never empty the system by opening the drain tap
Each ‘drain’ and fill dilutes the residual in the system.

One way to achieve what you are attempting is to run the boiler at low temperature, balance the draining and filling so that pressure remains steady and then leave one radiator open to system while others are closed to circulation
When water clear, open the valve on next radiator and close the one 5hat has been flushed

Heat mixes the water in the radiator being flushed. Cold flush ( like power flush) only clears the bottom rib on the radiator

Thanks for the reply @DP

Why do you think I will never be able to flush the system entirely,please?

The cleaner is only a 500 mL bottle and I checked out the size of all my radiators which totals 30 litres but obviously that would be plus pipework also
So if I said 5 L to fill all the pipework that would mean the cleaner only accounts for a 75th of the systems fluid

Surely refill bleed run and empty five times as I have now done it the water should be Running cleaner?

 

[gas112]

Thanks for the reply @DP

Why do you think I will never be able to flush the system entirely,please?

The cleaner is only a 500 mL bottle and I checked out the size of all my radiators which totals 30 litres but obviously that would be plus pipework also
So if I said 5 L to fill all the pipework that would mean the cleaner only accounts for a 75th of the systems fluid

Surely refill bleed run and empty five times as I have now done it the water should be Running cleaner?

Many years ago there was a chemical we used to put into systems to clean them out called DS9 and coincidence was it had to be filled and flushed 9 times and from every single drop then tested with litmus paper to make sure water was now neutral.
So you may have a good few more flushes and fills required to get it completely clear

 

[shd1970]

Many years ago there was a chemical we used to put into systems to clean them out called DS9 and coincidence was it had to be filled and flushed 9 times and from every single drop then tested with litmus paper to make sure water was now neutral.
So you may have a good few more flushes and fills required to get it completely clear

Thanks @gas112

So I think this is drain down number six or number seven and as you can see it is still extremely yellow in colour

Gotta say I’m actually regretting putting this cleaner in now I think and don’t understand why it’s not coming out if that’s what this yellow is indicating

 

[gas112]

thats a strange colour after all those drains and refills especially on a pressurised system was that also the initial colour or was it a lot dirtier as in brown /black .
Yellow/cloudy colour is usually flux residue which would have cleared after a couple of flushes

 

[dilalio]

thats a strange colour

Pish.

 

[shd1970]

thats a strange colour after all those drains and refills especially on a pressurised system was that also the initial colour or was it a lot dirtier as in brown /black .
Yellow/cloudy colour is usually flux residue which would have cleared after a couple of flushes

The colour has been pretty consistent @gas112
Always a yellowish colour and no, it’s never been dirty brown or black

 

[dilalio]

The colour has been pretty consistent @gas112
Always a yellowish colour and no, it’s never been dirty brown or black

Something is reacting!
Do you have a water softener?

 

[shd1970]

@gas112 here is the latest drain off water

Once it tails off, I shut 3 out of the 4 downstairs drains off and then flush that rad and it will go clean
I start with the closest to the boiler and then work away
I throttle the drain a little to fill the rads a little before opening again

Gotta say I’m like you, after this many drain and fills it should be improving, shouldn’t it, regardless that the upstairs radiators aren’t being flushed individually
They are being diluted significantly each time I refill