Mixer tap gives perfect bath temps, but scalding shower?

The bathtub/shower mixer tap (one faucet, one shower hose, two tap handles) can run a perfect and adjustable temperature through the bath faucet. But as soon as you pull the diverter, only scalding hot water comes through the shower head. The water pressure isn't great through either the bathtub or the shower, but it's enough, no complaints. The cold water tap rotates with practically no resistance, so I assume I'll need to tighten the internal screw, and I'll replace the shower hose just to eliminate that as an annoyance. Does anyone have any ideas why I can't get the same adjustable temperature through the shower?

5 Answers

could be unbalanced water pressures, mains cold tank feed hot
17th Aug 2018
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LAL Projects Ltd
4 Reviews, 100% Positive
Do you have a cold water tank in your property? If so please let me know
19th Aug 2018
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Birchwood Plumbing Services
1 Reviews, 100% Positive
I would replace the current bath tap to a thermostatic bath shower mixer tap, this will stabilise the temperature.
8th Feb 2019
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Pipe Dreams Services Ltd
1 Reviews, 100% Positive
If the Hot Tap works on the Bath fine then I can only assume the diverter has gone and thus will need new taps
30th Mar 2019
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Luke
2 Reviews, 100% Positive
First of all what boiler your using if a combi and 25 to 30kw the pressure want be great you cant add pump to combi. Your heat exchanger could be blocked if it was working ok before and you was happy with that little pressure but now it's gone.
22nd Nov 2019
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