old Thorn boiler - water heating problem

[ackers52]

My central heating system has two settings : - 1) water only and 2) water and heating.
The problem is both give similar unsatisfactory results. On water only - water gets warm, upstairs rads get hot,
on water & heating - water gets tepid and all rads get hot.

The only way to get hot water is by closing rads. This can be done in summer but is obviously not practical in winter. The water pump only appears to work on the water & heating setting.

The system has been drained and flushed and refilled via mains pressure tap and hose.

Any suggestions as to causes and remedies?
Thanks

 

[Gas2Air]

You have a gravity type system. Basically the boiler is always on for hot water in summer, i assume no cylinder stat fitted? The rads heat via gravity in the summer. You could fit an anti gravity valve after your pump to stop this.

The pump is only energised by the room stat if fitted.

However i would update your system to a fully pumped y/s plan, with independant controls, ie, room stat, trvs, cylinder stat.

Search the forum on such details. Money, money, money i'm afraid.

 

[wilhelm]

get boiler serviced? if its an oil thorn, then heat ex might be in an inch of soot?
turn boiler stat up?
maybe cylinder coil is furred up?
maybe pump is frekked?

 

[ackers52]

thanks for those suggestions - it is gas fire - not oil, and there is a room stat - but this doesn't seem to affect temp of rads. I think it has an anti gravity valve - if that is usually found along pipes from boiler (complete novice here - so please excuse ineptitute!).
Any other suggestions/advice gratefully received