Hot and Cold Water from Shower

DavidKlyne

We have not used the motorhome for a month so I drained down the water system, including disconnecting the pipe from the pump to full drain it just in case of freezing conditions. As it happens the weather has been reasonably mild during that period. Anyway we have just been to Chatsworth for 3 days. I reloaded the water system but when we used the shower it would go from very hot to cold and back to hot during the course of a shower. The other taps seemed to maintain the hot water flow. Can anyone explain the reasons for this and what options I have to solve this issue?

Thanks

David