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Nest is heating is working but not hot water

Kunle
Community Member

I have my Nest installed about 2 years ago but the hot water stopped working 3 days ago. There is heating but no hot water even when I use the manual mode. I need some help to give me a pointer on how to fix this issue. Many thanks.

1 Recommended Answer

That is the correct noise you should hear, as that should mean the relay is closing. I would think it’s not the thermostat problem, but most likely a motorised valve stuck or failed. Can you see one in your system? A little persuasion sometimes works, but if you are unsure I suggest your best bet is a plumber. 

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11 REPLIES 11

Frustratedddd
Community Member

Where are you located and do you have a Heat Link? Which thermostat do you have?

Hi @Frustratedddd, I located in Thurrock and I have the Nest Learning thermostat gen3 and heat link for controlling both radiator heating and hot water in a Pressure System boiler. Please let me know if you need any further information. Many thanks.

OK, just UK is fine. 

Try the following to see what happens. Make sure you only have one light on the heat link, and it’s not in manual mode. Check also your display is NOT calling for heat, ie set to 9 degrees. Make sure also on your display the yellow bacteria setting is not showing at the bottom of the screen. 

 

Then go to the display, NOT the app and go into settings and manually set the hot water to say 30 mins. Listen for a click at the heat link. You may need another person if to far away. 

Update what you find. 

Hi,

I have tested it as instructed, there’s a click sound in the heat link and nothing happens afterwards 

That is the correct noise you should hear, as that should mean the relay is closing. I would think it’s not the thermostat problem, but most likely a motorised valve stuck or failed. Can you see one in your system? A little persuasion sometimes works, but if you are unsure I suggest your best bet is a plumber. 

Hi @Frustratedddd,

Thank you for the quick response, I can see the motorised Value. Mine is Honey Value and I try and found a means of changing it. Many thanks

Looks like it could be the valve, but if you want to make 200% sure it’s not the heat link there is one more test you can do. You will need either a simple neon screwdriver or some form of tester or test lamps. Do you have any of those, or get hold of one?

Hi @Frustratedddd,

I have tested please send me the information about the test please. Many thanks 

OK, to prove hot water relay is working 200%, remove heat link cover by screw at the bottom. You will now see connections. Place probe on terminal N far left, and other probe on terminal 6. You should NOT have any power. Now with your 3rd hand!!! Press the heat link button, and you should now have power at those terminals. Press heat link button again, power should now be dead. Should that be correct, relay is working. I would then suggest valve is your issue.

Hi @Frustratedddd,

I was able to isolate the problem to be the motorized valve, the valve is now replaced and it all working as expected. Thank you for your help, I really appreciate your time and patience.

That's a good result, so many users think the thermostat is faulty most of the time. Good to hear your up and running again.

 

Well done Mods for RUSHING to help this user!