Problem with hot water

[MJS2]

Nest system was working fine. However, just back from few days away and can’t get hot water to work. It says “on” but remains grey on screen and boiler does not fire. When I start heating, the boiler fires and works normally but I can’t get the hot water to work. Please can you help?

many thanks

[chaconmorales]

Hi MJS2,

Thanks for reaching out to the Community. I am sorry that your Nest Thermostat is having trouble when getting hot water. But no need to worry, help is here.

Before we get started with further details, let me ask you some important questions

1. What type of thermostat do you have?
2. When was the thermostat installed?
3. Do you have a system or a combi boiler? Is the control On/Off or Opentherm?
4. What's the status of the Heat Link's LED light?
5. When did the issue start?
6. Has there been any recent work done on your thermostat(s) or heating system?
7. Were there any power outages?

In the meantime, here are some basic steps you can try to troubleshoot the issue:

Restart Devices:

• Restart or reset Heat Link: Press and hold the button on the Heat Link for 20 seconds until the LED slowly blinks.
• Restart Thermostat: Remove the thermostat faceplate and reattach it to initiate a restart.
• Check the following steps if possible:
  • Step 1: Check if the cause may be related to the initial installation
  • Step 2: Check the LED status of the Heat Link
  • Step 3: Check the Hot Water schedule
  • Step 4: Check the temperature of the water in the tank
• Check for Error Codes: If your thermostat displays an error code.
• Check that your system doesn't need maintenance.

You can check the following article for Domestic hot water control and for Heat Link lights and what they mean.

Please keep me posted. 

Regards,

Mario