This is one of those infernal intermittent problems! I have a twin impeller pump taking water from hot and cold water tanks to supply the shower. More often than not, this works fine and I get a good powerful shower. Ocassionally, however, it is not so good. By this I mean that the water temperature is fine but the amount of water coming through is much less than normal and sometimes it 'pulses'. If I turn the shower off, then restart it about 30 seconds later, it often (but not always!) resolves the problem. The problem seems to occur more often when it is very cold weather.
I am wondering if this problem is due to not having a Surrey or York flange fitted to the hot water tank - when my plumber friend (!) fitted the pump, he did not fit one.
The absence of a Surrey flange will only cause one fault - air being drawn in to the system. This would have been apparent from day one so is not likely to be your problem.
It might be worth checking any in-line filters fitted to either the pump or shower. Sometimes the debris moves about causing intermittent blockages.
Thanks Plumbbob. I supposed I was wondering if there was more likelihood of air being drawn in during very cold weather? But I will certainly check any filters asap.
I can't see the cold weather would make any difference to the flow of water unless the system was frozen and that would show as other problems elsewhere.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!