Y plan help

[Anonomoose]

Hi, Wondering if anyone can offer me some advice. I've just gone to a job to relocate and wire a new cylinder stat for a pressurised system. I wired it all in but could not get the central heating to work without the hot water being off. I spent a bit of time checking and couldn't figure it out as it was all done right (or so I thought) the existing wiring was a bit of a mess so after a bit of tinkering I thought it would be easier and quicker to rewire the whole system. After a lot of swearing and cursing I have been left with the same problem. no central heating without the hot water being switched off. Any help greatly appreciated as im all out of ideas.


Paul

 

[davesparks]

When you say pressurised system, do you mean a sealed system in terms of the primaries/heating or do you mean an unvented (mains pressure hot water) cylinder?

What happens if the hot water channel is on and the heating off with the cyl stat on?
And the same with the cyl stat off?

What happens with both channels on and the cyl stat on and room stat on?
Now the same but with the room stat off?
And with both channels on, room stat on and cyl stat off?

And now with the hot water channel off and the room stat on?
And the same with the room stat off?

You need to follow this logical process of each combination of the controls and taking note of what the valve and boiler does with each change of the controls.
Then just compare this to what should happen at each change of the controls and you should be able to establish what is or is not happening.