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Help! Something like a pump is making noise constantly

Community Member

Hi, I've put this under heating issues - but not sure that's correct. 

I moved into a property on 7th November which already has Nest 3 learning thermostat linked to heating system and separate hot water tank. For the last 4 weeks or so, there has been a constant sort of pump noise coming from the airing cupboard (where the hot water tank is) even when it's not scheduled to be on and the thermostat shows it to be off. When i say constant, I mean 24hrs a day. We scheduled in a boiler engineer as the boiler was due a service anyway, that then got postponed twice and sod's law, the noise stopped yesterday and the engineer came this morning. Without hearing the sound he was unable to diagnose and we couldn't force it to happen. He thought it might have been the heat protect/legionella thing which might have gotten stuck on for some reason but said if it was that then it's linked to the Nest rather than the boiler. Sod's law again - this afternoon it's started up again. I'm at my wit's end with this constant sound rumbling in the background when I go to bed and possibly using lots of unnecessary energy (the last 2 mornings while the problem hasn't been there the smart meter reading has been much lower upon waking in the morning).

Anyone any ideas what this could be or how to fix it? I am not technical at all - so will need any suggestions spelling out in simple language please!!!


Community Specialist
Community Specialist

Hi @K8S. Thanks for reaching out. I'm sorry to hear you're experiencing this issue, but we'll sort this out together. Let's start with a few questions:


What type of Nest thermostat do you have?
Did the issue happen during installation or after installation? Was it installed by a Nest Pro or by a regular installer?
Are there any lights on the Heat Link? Does the boiler activate when calling for heat by pressing the Heat Link's button to activate Manual Mode?
Are you seeing any wiring report or error on the thermostat and/or the app?
Have you had any recent power cuts in your area? If yes, has the power been restored?
Have you tried any troubleshooting steps before contacting us?
How many thermostats do you have?


Community Specialist
Community Specialist

Hi, I wanted to check in. Do you need any further assistance? If so, make sure to let me know.

Community Specialist
Community Specialist

Hey there, I haven't heard from you in a while so I'll be locking this thread. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community. Thanks, AlexD.