I wonder if any of you can help me? We are getting very tepid water from our hot taps & shower. It will run warm for about 5-8 seconds and then go tepid or cold for quite a while, before we get another few seconds of warm. A plumber has come out and changed the diverter valve and thermostat on the boiler (Worcester gas combi) - however, this has made no difference. She now says it may be the plate heat exchanger (?).
What I'm wondering is if it could actually be some tiny amount of cold mains water getting into the system from somewhere eg the shower. I wonder this because we used to always have a problem with the pressure in the system very gradually going down over time, whereas recently it has been much higher ie normal. Is it possible for this to be the case??
Am going to get another plumber in but would just like to know what you think, as at the moment we are spending money (which we don't have) on 'fixing' things that don't really fix it.