The red indicator light on the water heater switch which is wired to the pactrol micro 7 plus and the immersion tank no longer comes on. I can't get hot water using the pactrol timer for heating the main tank for normal everyday use but I can heat the water tank using the booster button. However this is inconvenient and expensive as I need to switch this on twice or three times a day depending on what we are using the water for. Do I need to get a new timer or heater switch ? Any help would be greatly appreciated.