During the winter I had a heating engineer out from scottish gas inspecting my boiler and radiators. He told me that I was wasting energy having both my gas boiler and my electricity heating the water in the immersion tank.

He turned off the electrical supply to the tank which was really nice of him. However now thats its summer, I still have to use my gas central heating to heat the water.

I've tried switching the switch on and off next to the immersion heater and also the switch in the kitchen that says water heater in many combinations. I've also had a look at the thermostat on top of the immersion heater itself, but it's also at maximum temperature.

Any ideas on how I can turn this back on?

I cant understand why he would have isolated the supply as there should be a switch to turn the immersion heater on and off.

If you know where your fuse/breaker box is (usually hidden away in a cupboard with your mains electricity switch) then you will probably find a seperate switch in there for your water heater, make sure this is set to "on".

Once this is "on", go to your immersion heater tank and make sure the switch there is set to "on" (usually looks like a light switch).

Check your circuit breaker board to make sure the breaker hasnt been pulled, it will clearly be marked "water heater" if it is sticking out then pop it back in.

Most combination gas heating systems as someone said before have a water only setting, which is more economical than the electric system as it only heats water as it is used, I am sure you will have something like this and wont need the electric water heater (except as a backup should the gas system fail) but best be in control of both.

If you have no joy with any of this, then phone the gas people and ask for the engineer to give you a call on the phone, they tend to have their own patch and remember individual jobs the guy who does ours even gave us his mobile number to save us having to wait days for an engineer through the helpline.

Hope this helps to get it sorted.

Successfully drained tank & removed old immersion - cleaned threads on tank - good as new - added ptfe tape - threads matct old heater exactly - but new immersion gets stuck after 1 turn - is there a lubricant I should use - Any ideas ?

Don't use ptfe tape. The new immersion should have come with a washer, add a sealant to this such as fernox LSX and it should go in ok.