Hot water zone - do I need it?

[tomg]

Hello,
my heating system has two motorised 2-way valves, one for CH one for HW.

Recently my HW valve stuck open, I freed it and all was fine. Yesterday I returned home to find my boiler had been firing all day - valve stuck open again - and motor in the valve is shot now too.

I could buy a new motor for £13.50, or alternatively I could leave the HW valve permanently open so that I always get hot water with CH.
I'd leave the CH valve in place to disable CH in summer.

what are the drawbacks? I'd never want CH with no HW. only one I can think of is no cylinder thermostat function when CH is on.

I think I'd prefer this - it would mean I always have HW in winter due to CH being on, without having to fire the boiler just for the HW.

Is there a strong argument for having a separate HW zone? Thanks in advance

 

[D_Hailsham]

If there is no valve in the HW circuit, there is no way of controlling the temperature of the hot water. So the HW temperature will rise to the same as the boiler. This means that you could have water coming out of the tap at 80°C, which is dangerous.

The recommended HW temperature is 60°C

 

[Agile]

Do you really want to run your CH all summer just to get hot water?

 

[tomg]

Do you really want to run your CH all summer just to get hot water?

no, CH will be off in summer, because the CH valve will be closed.

 

[tomg]

If there is no valve in the HW circuit, there is no way of controlling the temperature of the hot water. So the HW temperature will rise to the same as the boiler. This means that you could have water coming out of the tap at 80°C, which is dangerous.

The recommended HW temperature is 60°C

That's a good point, I hadn't considered how hot the CH gets!

 

[DP]

no, CH will be off in summer, because the CH valve will be closed.

You may want to read what you have written.

In summer, heating will be off, so how do you get hot water?

 

[tomg]

no, CH will be off in summer, because the CH valve will be closed.

You may want to read what you have written.

In summer, heating will be off, so how do you get hot water?

By firing the boiler with the CH valve closed and the HW valve open, which is how it currently works.

 

[JohnD]

... I could leave the HW valve permanently open so that I always get hot water with CH.
I'd leave the CH valve in place to disable CH in summer.

what are the drawbacks? ...

I think this has been answered now.

 

[D_Hailsham]

I fogot to mention ..... Building Regs require control over the hot water temperature.