Anti cycling

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The vSMART thermostat has a two week learning time where it adjusts parameters relating to if your property reaches temperature or not. This is also related to the weather conditions. Check the property location is set correctly in the app, reset the heating curve to default AND LEAVE IT ALONE!
 
Yes I read about the two week learning period.
Trouble is, house wasn't warming up so we were all cold.
 
I've noticed that vsmart heats my cylinder when heating is on even though HW is set to off in the profiles.
I've only asked for hot water on between 5 and 6am every day, but it seems to heat it whenever heating is on (in that it opens the HW valve when heating is on).
 
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I've noticed that vsmart heats my cylinder when heating is on even though HW is set to off in the profiles.
I've only asked for hot water on between 5 and 6am every day, but it seems to heat it whenever heating is on (in that it opens the HW valve when heating is on).
The VR66 has been wired or set up incorrectly, D.70 on the boiler is set to parallel heating, or the HW motorised valve is faulty.

Are you using the VR10 sensor on the cylinder or a standard cylinder thermostat?
 
Cylinder is a megaflo so just using the cylinder stat at the moment. Thinking of getting the vr10 though, just got to make sure it will fit along with the copper rods in the cylinder.

I thought d.70 was only used on combi boilers?
 
Cylinder is a megaflo so just using the cylinder stat at the moment. Thinking of getting the vr10 though, just got to make sure it will fit along with the copper rods in the cylinder.

I thought d.70 was only used on combi boilers?

D.70 must be set to 0 for HW priority (the boiler operates with ‘extended combi logic’) and the rotary switch on the VR66 set to 1.

If both valves are open together your return temperature would be seriously skewed for heating, affecting the learning of the vSMART.

Maybe worth adjusting D.1 to 15 minutes to even out radiator temperature (the zone valve remains open for the length of pump over-run), and set your boiler temperature to maximum so vSMART has the complete flow temperature range to use.

There is no benefit to reduce your HW heating time to a short period per day. You always need HW tomorrow. The heat lost from a modern highly insulated cylinder is negligible. Having longer times, or even left on during any times you may need HW during the day ensures the boiler can reheat the cylinder as and when the temperature drops. In practice this is no less efficient. Reheating a modern cylinder from cold should take 20-40 minutes tops. Reheating it as it’s being used a lot less. Using a VR10 is better than a standard cylinder thermostat.

However, if using a non-Vaillant cylinder the overheat thermostat should be wired in series with the zone valve to maintain G3 regulations if using a VR10. Any work relating to the safety devices on an UV cylinder must be carried out by someone with the relevant UV qualifications.
 
Also what temp is the cylinder set to on the megaflo. I believe that we can run them much lower than the normal recommended 65c when using an unvented cylinder as the water is stored direct from the mains rather than stored in a header tank in the loft. I think there was an additional logic on the old VR series that if you set holiday mode then just before you comeback the boiler does an anti-legionnaire program just before it expired or maybe I am tripping again? I would get everything working properly before the Vr10
 
d.70 Is set to zero.

VR66 wired as instructions and set to monomode (switch to position 1)

Need to check if valve is faulty.
 
However, if using a non-Vaillant cylinder the overheat thermostat should be wired in series with the zone valve to maintain G3 regulations if using a VR10. Any work relating to the safety devices on an UV cylinder must be carried out by someone with the relevant UV qualifications.

You mean the cylinder stat is connected in series with the live feed to the valve motor, right?
I've read a bit about that on here from others.
Seems there are two schools of thought on it. Some say don't need to as G3 regs say the boiler itself can act as the overheat protection.
Others say you need it.

Personally, I think it better to include the cylinder stat within the valve motor power supply. Everything's already there so no extra effort to wire it in and it offeres an additional level of protection.
 
What's always in this mode? d.70 ?
Yes I agree zero is the default setting for d.70

Or are you referring to something else?
 
Is it possible for a motorised valve to only partially close?

When heating is running, the pipe run after the cylinder valve is warm. Not as warm as the heating pipework but it is warm.
So I'm thinking the HW valve is not fully closing.
Does that happen?
 
With my old setup (simple on off control) I'm pretty sure the pipe to cylinder post valve was cold through out the day. It would of course be warm whilst the cylinder was being heated and for a little while afterwards (timer was set between 5 and 6 am).

I've checked the VR66 is not calling for the HW valve to open whilst heating is on.
 

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