Potterton Housewarmer

I\\\'ve got a pottorton housewarmer 45 backboiler. Lucky me !!! NOT !! Have just bought the house and have very noisy upstairs radiators. Also they stay on constantly. Found that the upstairs radiators are connected to the hot water tank !!! so are always hot when the tank is hot. Downstairs are connected via the boiler. IS THIS NORMAL!!!?, Seems strange to me !!. Not sure if this boiler is meant to be a combi because can\\\'t find a diverter valve and also the boiler seems to fire up every 10 minutes or so to keep the water tank at a certain temperature. Is this Normal Too !!??? HELP !!!!!

Having a diverter valve doesn't make it a combi.
The boiler firing up every ten minutes to keep the hot water cylinder ( not water tank/cistern)at the desired temp is normal, if it didn't your water would lose temp.The control will be a boiler stat or a cylinder stat
Of course the better the insulation on the cylinder and pipe work the longer it takes to cool and the longer the time interval.
It's normal to have the bathroom radiator on the hot water side so at least that room is kept warm when heating is off.
In your case it would only make sense if you had zone/diverter valves and a programmer so that the on/off times of the zones could be different.
If the radiators are noisy I would try bleeding them and perhaps lower the pump speed.
One thing a combi will have is a pressure gauge and what it won't have is a water tank or a cylinder. Mains water goes in cold and leaves hot to your taps. Heating water is totally enclosed.
These are my thoughts only, someone may disagree

Brilliant, that helped me a hell of a lot. Have actually re plumbed so that the whole central heating system comes from boiler and not upstairs from the hot water tank. This has stopped my central heating firing up each ten minutes and instead now fires up about once an hour due to the heat from the tank not being all lost through the upstairs radiators !!! And, as you pointed out, I have a Stat on my cylinder. This was set way up at 75oC so that it kept firing up to maintain this temp. Have dropped that right down too. !!!

Cheers for help,

Brian