Have you read the book and if not why not  

The heat slave holds 10 gallons of hot water at whatever temperature you set it  at ideal below 60c.

The diverter valve is normally closed to the heating and is powered open when theres a demand from the boiler, room stat or other controls.

Room cold will be down to the radiator sizes and should have been calulated to suit the required temperature.

The pump should be on 3 and nothing else it also has an over-run switch to disipate excess heat.

If the facia mounted operating switch or programmer is set to off or set to heating only then only the pump will operate.

Get the installer back to check it out

psssst, if you turn the hot water stat fully anti clockwise it enables the rads to heat up faster.

[quote author=markadams  link=1135596503/0#2 date=1135616108]Hi John,

Happy christmas, I hope you are well.

As for the heating problem, I was not saying that the rooms get cold (the rads go cold even when the room stat is still asking for heat and the heating is switched on).

As I said the burner comes on for a while the it turns off and the pump continues to pump (warm) water, even when the room stat has not reached temperature.

I may be silly but I thought that combi's heated the water on-demand so you do not run out of hot water?

Mark.   [/quote]

And a happy new year to Mark  

Mark you must understand the heatslave is technically not a combi in the true sense of the word, its a combination boiler that incorporates a store of domestic water that reheats rapidly when you draw water to supply 17ltrs/m at the taps.

All the time you are drawing water the heating will be off the same as a normal combi.

Heating works by having a demand from external controls, once satisfied the pump will disipate the excess water into the domestic store, the temperature range is 52c on to 82c off with a differencial of 5c in which case there will be some delay in the boiler firing.

Was this a diy job   did you fit the 3 probes in the pocket on the left, and the domestic probe in the front of the tank.

is the system sealed or open vented, have you used plastic pipe.

I would be inclined to get them back to check a few things out.

Should be call for heat, pump on, diverter valve should open (you can see this) boiler on.

The boiler when it reaches temperature should shut down on the stat but the diverter should still be open check it out.

You could have a wire or link missing  ???