Help cleaning central heating system please.

[bokkie]

Hi all.
My central heating is getting a bit noisy and i think it's time to stick some cleaner in it..
problem is, last time I did it, it took hours to get all the airlocks out the system, and it caused me to panic ever so slightly.
I know it's not just me as a heating engineer had the same problem as well, he ended up opening my towel rad valve and blowing in there to get it all moving.
Question is. Instead of draining the system, could I just open the drain valve, leaving the ball valve in the header tank open, so that it flushes clean water through as it's draining.
Then close the drain valve, add the system cleaner and run it for the required time.
Then when it needs to be cleaned out just open the drain valve again and leave it for a while, leaving the ball valve open so that instead of draining, it is flushing.
The theory is that as I'm not draining it, there should be no airlocks .
Any thoughts?
Thanks all.

 

[Agile]

Thats actually a better way to do it. I call it dynamic flushing! Kamco took my description and added it to their web site.

But you must have the heating pump on while doing that so its circulating the water.

Tony

 

[bokkie]

Thanks for your quick reply. So I should switch heating on, attach hose, open drain valve and just let it flush for 10 minutes or so.
Then when I add the system cleaner, should I empty just the header tank and then add it to make sure it gets in there?
Maybe even add it to the header tank, and close the drain valve about 30 seconds later so that the cleaner is drawn in?

 

[bokkie]

Would Fernox f3 be the best stuff to use?

 

[Terry lambert]

Even with a running drain, which is the method you describe, you will have to fully drain and empty the system to get all ofthe cleanser out. You will also have pulled in air and a partialy drained system can be tougher to clear sometimes.

I would tie the ballcock up, bail some water and add the cleanser, let it run for a week before fully draining, re fill, then running drain, then empty again and then add inhibitor.


If you get air locked you can always post back for adviceto clear it.

If your system is very dirty, you will need equipment and knowledge, and so I would suggest getting someone in.

 

[bokkie]

Thanks for your reply. Surely if I just left it running for about 20 minutes it would get rid of all the cleaner in there?
I just really want to avoid draining the system if at all possible. I remember what a nightmare it was the last 2 times. Took the heating engineer and I a good couple of hours to get all the airlocks out.