can i swop old timer unit for a digi one?

[warbulator]

just moved and new house has old heating system. i drained cleaned and chemical flushed it etc and its bouncing hot. The pump was noisy so replaced it and now i,m kicking myself 'cos it and the motorised valve are under the f/room floor and i didnt take much notice of it with the floor up, i,m assuming if its a 3 port valve i could replace the old clockwork randall 103 with say a sunvic ,so h/w and heating can run separately, currently with room stat down can have only h/w but if heating is on its heating the tank too ( bit of a waste).

 

[DeltaT]

The 103 is a single channel timeswitch, so it doesn't sound as if you will have all these controls??? Perhaps it would be better to get a good recommended Plumber in for a look.

http://www.penlane.co.uk/sitebuildercontent/sitebuilderfiles/newrandall103.pdf

 

[Whitespirit66]

Sounds like you aren't sure whether you have a 2 or 3 port valve.

It sounds like you might have an old system with a single 2 port valve, poss. controlling the rads. If you have, then the HW water will be on all the time that the system is in use. If this is what you have, you need to add a second 2 port valve to the HW, and wire the system as an S Plan. This will give seperate HW and CH control.

3 port valves should already give seperate control, so I reckon yours is a 2 port.

 

[warbulator]

thanks for the replies. the tank has its own stat which when turned down still allows the heating to run, does this suggest a 3 port valve?.
i spoke to the previous owner and he said 2 years ago the heating was working fine but the hot water was inopp and he was sure that they had to replace a motorised valve under the floor.
so it appears both can run separately if i keep turning the h/w tank stat down
when not req or visa versa ( bit of a dodgy way to do it though!)