Tepid bath - plumber or electrician?

[WinifredBanks]

I can no longer get very hot water out of our bath taps; do I need an electrician to look at the thermostat on the bath and the boiler, or a plumber?

Thanks

Thanks PigletJohn, the bath tap is a mixer tap with a thermostat attached

How many knobs (or levers)?

There is one lever to control the temperature (with a little red button that's supposed to warn you when you take it over a certain temperature), and one lever for the flow.

Also, one lever for the overhead shower and one for the hand shower are also on the bath panel

I think the fundamental problem is that the pressures are not balanced. Ask around for recommendations of a local plumber, who I think will be able to find the cause and reduce the cold pressure to match the hot.

Or, next time the boiler is due a service, tell the engineer when making the appointment that the hot pressure is lower than the cold, and ask them to allow enough extra time to investigate why.

The mixer will never be able to manage the temperature properly when the pressure of hot and cold do not match. The cold will always tend to overwhelm the hot.

Thanks very much for your help