flushing CH system

[bongos]

Bit of advice if possible. Last year I had to replace all my old TRV as they were all knackered. This resulted in me flushing the system several times which brought out alot of dirty water as you would expect.

Is it of any benefit to flush the system again within a year or am i just wasting my time. My boilers a Trianco 25/45 and must be getting on for around 15 years old. Last time I flushed it the CH system was alot quieter but I dont know if this was just helped by the fact that my TRV were now working!

Any advice appreciated. Thanks

 

[Agile]

Its really more a matter of seeing the colour of the water!

If its any darker than a light straw colour it might benefit from draining and refilling.

If its really dark then it needs draining an drefilling with suitable chemical and then draining and refilling with inhibitor.

Tony

 

[bongos]

when i drianed it last year it was dark grey but i assumed that it was because it hadn't been done for a while. After 3 flushes it ran clear. I'm sure there would still have been some sludge left in the system though.

 

[JohnD]

draining the water out doesn't do much to clean it.

Did you refill it with inhibitor? If not, it will have corroded more since you last filled it.

A chemical clean will loosen a lot of stuff that you didn't know was there. I put some X400 into a system i had previously plain-water flushed and fited with a magnaclean and seemed clean, it loosened heaps of black sediment that circulated round and was collected by the magnet.

 

[bongos]

might give it ago with some chemical cleaner then. My guess is that it has probably not been cleaned properly for some years.

 

[JohnD]

If you can afford an extra £80 or so, fit a magnaclean on the return as well. You will be surprised and delighted at the amount of grime it collects, and continues collecting for months after you have completed your clean.

 

[AlanE]

To give you some idea of the way sludge blocks heating systems think of a length of gutter slightly sloping with a hose running water along it.

Now add some sand to that end and whilst the water will spread the sand along the length of the gutter very little will be washed off at the other end. Keep adding sand and again it will just spread it along the length of guttering.

This is exactly the same with the sludge, it is spread along the lengths of pipes and the bottom of radiators. Simply flushing with clean water will remove little of it and the water will seem to run clean (just like the gutter example) whereas in fact the pipes can be almost blocked.

Some advocate removing the radiators and flushing in the garden - cleans rads but not pipes. Without a little help, chemicals, the sludge remains. Best solution is dose system with cleanser and follow that couple of weeks later with a powerflush.

Dose with inhibiter and the process should never need repeating provided inhibiter strength is maintained.