29 Oct 2015
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United Kingdom
hi there,
i am new to this forum and can someone please help me with an issue i am facing with my CH system?


i cleaned the system with X800 and left it in for a week after we had our radiators replaced with new ones about 2 months ago. i then refilled and drained the system three times to get rid of all traces of the X800 and then added X100 inhibitor to the system.

i thoroughly cleaned out the F&E tank in the loft before adding the inhibitor. it has now been over 6 weeks now and the tank is now covered in white foamy goo.

i added the inhibitor at the beginning when i refilled the system the 4th time (after closing all the drain ports) to make sure the inhibitor went into the system and not stay in the tank.

i dont want to drain the system and i know i will have to clean the tank out with the ball valve up but can someone please tell me why this has happened and how to prevent it?

the tank has a lid and is insulated.

also, the past few days, the boiler seems to be playing up. its a potterton supruma 50l and when i call for heat or hot water, the green/ yellow light keeps flashing every two seconds and about an hour or so later, the boiler turns on.

i dont know if the boiler is doing this due to the white gunk as i put a whole tub of X100 in and made sure it went into the system when i re-filled it after fully draining it. we only have 7 rads and a litre treats up to 10.

your help and thoughts are much appreciated.

thank you.
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With all new radiators the correct cleanser is X300.

X800 is for heavily sludged systems.
Your vent pipe must be pumping over if loads of that has ended up in the F&E tank!
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I think you're gonna have to drop the system again (empty it) and leave the ball valve into the F&E tank running so that you can use the clean water to flush everything through and get rid of all traces of the x800 and (unfortunately) the inhibitor. Maybe it's just the foam that's expanding into the F&E via the vent pipe! When you're rid of it though... Check that you are not having pump over issues.

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