Ideal Mexico CF75 CH without HW being on??

Hi, apologies for the long first post, but I'm struggling...

I've just moved into my new house, and am trying to fathom out the various "features" of it.

I've come across this one, and hoping someone can help.

I don't appear to be able to have just the central heating on without the HW also being on.

From what I can work out, it's a Pumped CH, with Gravity HW.

I can't see any valves anywhere.

Here's what happens....

The programmer has the normal HW on/off along with CH on/off buttons.

When using the HW stuff it's fine. However when using the CH one's, all that seems to happen is that the pump is turned on.

I did some further investigation, and found in the basement (where the boiler is), there are two sockets on the wall. One has the boiler plugged into it, the other the pump.

I've put a meter on them, and confirmed that the programmer only turns on the pump one when the CH is switched on. The one actually powering the boiler only goes live when the HW is switched on.

This can't be right can it? The system appears to have been installed in 1981. I've recently changed the room start (Drayton Digistat3) and the programmer (Drayton Tempus7), but these have made no difference.

Does it need re-wiring, and if so, how do I do so? Should the boiler be on a perm live, with some other sort of switching? Is the boiler even capable of the two seperate tasks?

Any help or advice gratefully received.


Shaun

You need to adjust your programmer (see installation instructions) to always bring HW on when CH is selected. Alternatively you could convert your system to a fully pumped one, but that is quite complicated and expensive. What's the problem with having HW on when CH is selected?

This is exactly how gravity hot water and pumped heating systems work.
As Chris mentions the programmer should have a LINK setting (usually on the back in the form of a dip switch or link pin)which means if you press the CH button it will automatically bring on DHW

Thanks for the replies guys, that's just what I needed to hear.

I just found it a bit strange, I've had sealed systems in my last two houses, and you could always do bits indepentantly.

So I suppose my question is, am I wasting lots of energy by having the HW on while the CH is on? Is it worth getting the system converted?