No hot water

[Ash11]

My hot water has stopped not working 

The system has been installed for over 3 years with no issues 

Recently the water has not been very hot 

On investigation it appears that although the Nest thermostat shows the water to be on on the timer and on the boost function it is not firing the boiler. The heating function is working fine the hot water is switched on in the settings and we have had the system checked over by the installer and also the boiler with no issues. 

We are getting some hot water only when the central heating (and in manual mode when both hot water and central heating is on). 

In the app

Turn on - no clicking on heat link  app colour orange

Turn off - no clicking on heat link app colour grey

Boost on - boiler silent, no clicking no heating app colour orange

Boost off - same. App colour grey

can anyone help with a solution

[Frustratedddd]

 You say the installer says everything is OK, so what exactly is the problem if they say no issues?

I assume from your description you have a system boiler? That would mean you will get some hot water as the boiler when calling for heat will run, and when passing round the system it will heat the H/W tank. This obviously will only happen when calling for heat stops, and the pump stops, there will be no circulation of the water.

Start easy and forget the app for now! Check you Heat link, and make sure you have just the one green light on, and the display is NOT calling for heat. Check the hot water is not in boost mode and is not calling for water in the schedule. Once all confirmed, go into hot water boost and turn the boost on for say 30 mins, do you hear a click a the heat Link? You may need another set of ears to listen while you turn on the boost, then stop the boost to see if you hear a click again. Like I said, do this manual NOT the app. Update if you hear any click from the heat link relay.

[Ash11]

Thank you.  Yes system boiler. Bolier guy is saying thermostat issue.  

Have tried what you suggested but no click from heat link.  Have reset as well and redone everything (and ensured hot water in settings is set to on and in the hot water section as well). 

On heatlink there is only one light but on manual all three lights on and hot water works. 

do you think new thermostat needs changing?

thank you. 

[Frustratedddd]

I would say it's a faulty Heat Link relay, reason being, no click when water manually set. NOT the display. Hence the checks I asked you to look at.

When you press manual mode you will get 3 lights, that's why I said make sure everything is off before you started. One light just shows the H/L has power.

Are you handy with a screwdriver, and more important do you have a tester or a simple neon screwdriver?

[Ash11]

hi Frustratedddd

Thank you for your help. Yes handy with a screw driver and have a tester.  

[Frustratedddd · Accepted solution]

First make sure you have only one light on the H/L and no schedule is calling for water.

OK, remove the H/L cover by the screw at the bottom, you will now see the connections. The H/W relay is Terminal number 5 & 6 or should be. To confirm, you should have a cable in both 5 & 6 terminations. Assuming you have a standard tester with L/N probes, put neut probe on N far left, and red on L adjacent to the neut. You should have 240v ish.

Now to prove relay is switching, keep neut probe on the N, and live probe on Term 5. You should again get 240v ish

Next, keep neut probe on N and put live probe on Term 6. Should be dead, no voltage.

Next, press the H/L button while still holding the probes on the above connections. You should now see 3 lights on the H/L and the voltage should now be 240v ish on your meter. Turn the H/L button off and voltage will be dead again.

Should that not work, duff H/W relay.

If you just have a neon screwdriver, much easier, just put neon on Term 6 and press the H/L button and you will see the neon light up, turn H/L of neon will go off. That doesn't work, duff relay.

[Ash11]

Amazing - will give it a try in the morning and let you know.  Thank you very much for all your help. 

[Ash11]

Hi Frustratedddd

Tried the steps you kindly recommended and get 240v when I turn the HL on and nothing when off.  So looks like HL is working properly?

Everything works on manual mode - so I’m thinking maybe just change the HL device and see if it works. What do you think?

Thank you again for your help. 

[Frustratedddd]

Well if everything is working correctly at the heat link it can’t be that, so no I wouldn’t change that.  I would probably check that everything is working correctly at the boiler. Common issue is motorised valve for example.

You say the relay is switching, which would say the boiler connection is the issue. 

[Ash11]

Great - will ask the boiler man to check again. 

thank you for your help.