problem with shower

[thelewisgang]

we have this Mira shower - the type that takes water from the hot and cold water supplies.  When we have the central heating on the power is reduced and it runs only lukewarm (sometimes cold). We have to turn it off and then on again, sometimes several times, before it comes through ok.  The thing is, when we don't have the central heating (radiators) on, its fine and never gives any trouble at all.  So, if there are any plumbing people on here, we would be pleased to have any suggestions. thank you.

[delboy3]

I'm no plumber but to me it sounds as if the central heating is circulating the water from your tank through the radiators, and therefore there's not much left to reach your shower. You can either switch off the central heating before having a shower, or look at installing a new boiler. But as I said, I'm no expert...

[thelewisgang]

thank you for replying. Unfortunately, its not as simple as switching the heating off as it seems that once the radiators are and have been on, just by switching them off seems to make no difference at all with the shower temperature/flow.   Its only when we never have the radiators on at all, like in the summer, that the problem disappears.  All very strange really.