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Just in the process of removing a toilet. So shut off the mains supply at the stop cock started to drain down the system by running downstairs taps until pressure started to wear off, then I had a thought - what about the mains pressurised unvented CH system which was installed 2 years ago so i'm not that familiar with it yet!?
I had a look in the airing cupboard and located the mains supply to the system which had a large shut off valve, I closed the shut off valve and continued to drain down the system by running cold taps until they stopped running. Terminated the toilet cistern mains supply (didn't have a ball valve fitted unfortunately which would have made this task so much simpler because I just could have isolated the toilet - why don't plumbers do this when installing things?!). Removed the toilet, switched on the water supply at the stop cock and opened up the CH shut off valve.
Obviously everything appears to be fine, but i'm unsure about the effect on the mains pressurised unvented CH system - I kind of feel I should have closed the shut off valve first before shutting off the mains and starting to drain down the system.
Is there anything I should do to re-pressurise the CH system or attend to it in some way?
Thanks.
Unvented means it is sealed.
Closed loop system so no need to do a thing.
Your unvented CH system is sealed. Just leave it alone and it will be fine. It will have a filling loop that connects it to the cold water feed. This is only used when filling the CH system up. The filling loop "should" be disconnected to avoid someone who doesn't know what they're doing opening the valve and overpressuring the CH system to 8bar or something silly and it looking like an episode of Das Boat.
Cheers chaps. With it being an unvented system I just wondered if I needed to bleed out any air that got into the system from me draining down by running the cold taps as air tends to find its way to the top of the system which happens to be the hot water cylinder and the expansion tanks.
Anyway I braved turning on the system and it seems to be running happily with no error messages coming up on the boiler display. So far so good.