Combimate security ring stuck

[losimagic]

Hi,
We've inherited a Combimate system, which appears to be working, but the combiphos needs to be replaced.

However, the big silver security ring is stuck and we cannot loosen it.

Can anyone suggest a way we may be able to free it?

many thanks

 

[snowhead]

Pour warm to hot water over the ring (it should expand very slightly) and wear rubber gloves to get better grip when releasing the ring.
Have you removed the drain bung to release the pressure?

https://www.combimate.co.uk/wp-content/uploads/2021/07/Combiphos-Refill-Instructions-website-CRL-1-A-02.pdf

 

[losimagic]

Pour warm to hot water over the ring (it should expand very slightly) and wear rubber gloves to get better grip when releasing the ring.
Have you removed the drain bung to release the pressure?

Yes, luckily the red spanner was still with the system so we could do that.

Thanks for the suggestion, we'll try it!

If we still can't get it off, I'm guessing that whilst it's an option, it's not a great idea to leave what little combiphos is left in the system (looks like it's 'melted' together) and top it up as much as we can through the bung hole?

 

[losimagic]

Pour warm to hot water over the ring (it should expand very slightly) and wear rubber gloves to get better grip when releasing the ring.
Have you removed the drain bung to release the pressure?
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Thanks, that worked perfectly, however we have a new problem!

We took it apart, meticulously cleaned out the inside, made sure there was no residue left anywhere - also removed the "red spike" at the back of the unit, as there was 'gunge' around that.
We put it all back where it came from, new o ring seal, replaced the security ring and bung - both to finger/hand tightness - and refilled the unit with crystals.

Once the cover was back on, and the water was turned on, we heard water flow into the unit, no leaking - SUCCESS! we thought

When taps are running in the flat, there is now a gentle drip from the combimate, in the middle, at the back against the wall.

Have we missed something?
Should we dismantle, double check cleanliness and try again?

Thank you