Getting Nest to call for hot water at the same time as heat

[patrickmays]

Hi guys,

I recently purchased a Nest thermostat to get some efficiencies from heating, being able to control it remotely etc etc.

I've got an ancient boiler though and basically the central heating doesn’t come on unless the hot water is on too, I think something to do with the way the valves are setup...

Anyway, I’m getting around that by setting a timer on the hot water for the kinds of times I want the central heating to be on which is ok, (that’s how it worked before I had the Nest so the hot water and central heating were timed to come on at the same time and the thermostat would kick the heating on and off).

It's a shame though because if it get's really cold at night (outside of the hot water timer period) the Nest isn't able to kick in to provide heat because I don't really want the hot water to be on 24/7 and also it is a bit of a faff turning the hot water on when you want the heating to come on.

The hot water is done on demand by the boiler though and we never use much hot water anyway so was thinking it's a bit of a waste to have the hot water on all the time during the timed period when there is no need for heat. Because of that I was wondering if I can just take the hot water off the timer and just put a bridging wire like the diagram attached?

So when the Nest “calls for heat” it will “call for hot water” at the same time and it will work without having to keep the hot water going constantly when we don’t need heat.

Is it ok to do that or would it blow the whole thing up?

Thanks in advance!

 

[Chalked]

Hi
You can wire it up however you like. But you will always get hot water when you fire the boiler. It's how your system us piped up.
There are ways of adapting your system. A basic one is a "C" plan, where a motorised valve is fitted on the hot water primaries. This works, but if possible, altering the system to fully pumped, with motorised valves controling the flow of water to heating and hot water seperatly, is the best.

 

[patrickmays]

Hi
You can wire it up however you like. But you will always get hot water when you fire the boiler. It's how your system us piped up.
There are ways of adapting your system. A basic one is a "C" plan, where a motorised valve is fitted on the hot water primaries. This works, but if possible, altering the system to fully pumped, with motorised valves controling the flow of water to heating and hot water seperatly, is the best.

Ah ok, that's cool I'm fine with getting hot water I just want the hot water to be able to come on when the nest calls for heat and not have to fanny with hot water control. So you reckon it won't blow up if I did that? 🙂