Nest thermostat cannot turn on hot water

[WT01]

I have just installed a new system boiler with hot water tank and connected it to the Nest to control heating and hot water. The heating is running normally.  But when I tried to turn on hot water (both by boosting and schedule), the boiler switch on the heating instead. However, both the Nest thermostat and app showed "hot water on" and "heating off" but the boiler showed heating on and hot water is not on! Any suggestions on how to resolve it?

I have tried resetting the Nest to factory setting and reset everything but the problem still persist. 

[Frustratedddd]

I assume you have a Heat Link in the system, correct?

Who installed the thermostat to the new boiler?

Upload a picture of the Heat Link terminations to start with, and we can go from there.

[WT01]

Thank you Frustratedddd! Yes, I have the heat link installed by the plumber.  Please see photo

 

[Frustratedddd]

That’s the heat link, but you do not show the connections inside the cover!

[WT01]

Sorry! Here it is. 

 

[WT01]

An update....I tried to turn on hot water just now and nothing happened to the boiler, the heating not turned on. The thermostate and app showed hot water on but screen was still grey, not turned irange. 

[Frustratedddd · Accepted solution]

The connection terminals are in the correct ones, but you would have to check terminal 5 to confirm if that is a live feed! 

My guess is terminal 5 needs to be investigated. Another issue could be at the boiler, as some have a link to be removed or fitted. Either way the install needs correcting. 

Your schedule and app would show working if that isn’t live, but  needs to be a live feed to switch the relay. 

I would suggest getting the plumber back to check that out, and at least leave your system working correctly. While you have him there, might be a good idea to confirm where the earth wire is, although the heat link is double insulated, the cable feeding needs to be protected! I can’t see any sign of an earth! 

I hope that makes sense?

[WT01]

Thank you again for your advice. I will pass your message to my plumber.