I've recently had a new bathroom put in, with a mains shower (used to be electric). But now my shower keeps running hot-cold-hot-cold every minute or so. My bath tap and sink tap in the bathroom are running fine, it's just the shower.
I was told this shouldn't happen as I have a combi-boiler but without fail, every shower I take is the same!
Can anybody tell me why this is? Do I need to get my boiler checked? Is there anything I can do?