Heatlink wiring issue

[Alcaza]

Hello,  I have some issues with my newly installed heating system. 

I have 1 combi boiler, 2 nest thermostats ,one upstairs and one downstairs. 

The heatlink and thermostats working fine and turning the boiler on/off on demand. 

The only issue is, I have two additional water circulation pumps because the house got underfloor heating with a lot of pipes and therefore water, installers said these pumps are absolutely necessary,  the combi boiler can't cope with that amount of water.

They wire the water pumps to the "hot water" relay which I  scheduled to work 24/7 in Nest app.

But I would like to know, how could I wire the pump to work only when the specific termostat ask for heating. 

So to turn on pump for upstairs only when upstairs thermostat turning on the boiler.

Is this possible somehow? 

Or to link the function of these two via app?

I have some pictures of the pumps and the curent wiring of the heatlink but not sure how to upload here. 

Thank you very much for your help!

[Frustratedddd · Accepted solution]

Now I am confused! Which country are you from? Are you 240v ac in the house?

Can you confirm the voltage at terminals N & L

[Frustratedddd]

First of all you have to login to upload pictures.

Who did the wiring for your heating?

Are you saying, you want to run Pump 1 the same time as Thermostat 1 calls for heat, then when the thermostat cuts out the Pump 1 stops also?

[Alcaza]

Hi, 

I still try to upload pictures. 

The plumber company who did the whole underfloor heating installation, they wires the thermostat.  They are old style plumbers, not up to date with modern thermostats. 

Yes, I like to have turned on the boiler same time as the pump when thermostat request for heating. When thermostat cut-off the heating  the pump must stop as well, just like the boiler.

[Alcaza]

[Frustratedddd]

I’m probably not the person that should be answering your question at the age of 68 in that case! I could use the rule of common sense, and say ALL the Heat Link and thermostat is a switch! 

One thing you need to do is get those old style plumbers back to connect the most important wire! The Earth wite. Why would anyone cut the Earth wire off when there’s a connection staring at them in the Heat Link?

By the way, just connect the pump feed wire into terminal 3, job done!!!!

[Alcaza]

I texted and called him several times.  He said he cannot help with this thermostat, because if I would install his own thermostat (for extra charge) he could fix the issue but he is not electrician so he can't help any futher with nest. It does work on manual button press and that's it.

[I owned these thermostats from my previous house so I told him I like to use it, and not to buy new ones.He had in his car another thermostat which can control 2 zones (1st zone is boiler, 2nd zone would be the pump)]

I am awaiting a proper electrician,  I am afraid to do any changes before.

The plumber said, ce cannot put the boiler and pump to the same relay because that would burn the mainboard of the boiler, he not suppose to give 220V to the boiler here

Sorry for maybe stupid question, but where exactly I suppose to have the earth connected and from where I must put a jump wire to terminal 3 exacly? 🙂

Thanks!

[Frustratedddd]

Basic electrics I’m afraid! The Earth wire is the most important wire in any installation, the other wires just make things work!

Terminal 3 goes to the boiler and becomes live when calling for heat. Basically all the Heat Link does is convert the 12v connection from the Nest display to 240v. Therefore all the connections at the Heat Link are 240v, now if terminal 3 goes to the boiler it will be 240v.

i thought you asked the question is it possible to run the pump at the same time as the display calls for heat? The answer is yes and the connection so simple, but I’m not expecting you to do that. Any GOOD electrician/plumber will sort this out in seconds.

[Alcaza]

Thanks for your reply. I spoke with the plumber again, he said it is not possible to jump connect the two relay's because it the electric voltag from boiler is low voltage and the auxiliar pump is working on 220V so if I connect together this will burn the boiler motherboard....

He said the only solution is additional relay to control both devices with one command from thermostat. 

Today the electrician will arrive,  I have all my hope in his knowledge. 

[Frustratedddd]

I bow down to the superior knowledge of the plumber who installed you system, and left the Earth wire disconnected at the Heat Link!!!

By the way, the pictures you uploaded is that the final job, finished, done, completed, signed off?

Put it this way,

Terminals...........

N = 240v Neutral

L = 240v Live

1 = 240v normally closed contact

2 = 240v Common Live feed

3 = 240v normally open contact

4 = 240v normally closed contact

5 = 240v Common Live feed

6 = 240v normally open contact

The only low voltage terminals in the Heat Link that would be any use in your installation would be T1 & T2, and that's 12v to give a supply feed to your thermostat display. Obviously not connected as your display is on a stand.

This means all the above connections are 240v, and from what I can see terminals N, L, 2, 3, 5, 6 are connected by 240v. This in turn means, when you call for heat from the display, terminal 2 & 3 close which then sends 240v power to your boiler feed!

I have added a picture for you to see of page 10 of the install manual that comes with your thermostat. That will help your electrician when they come to advise you.

Unless I am missing something in your request, I cannot understand what they are saying.

Good luck.

[Alcaza]

Hello,

The electrician appears and he said the same thing like the plumber.

We can't connect the two relays with a jump wire because the boiler got 35V and the pump 220V.

As I understood the 35V comes from boiler into the heatlink and the heatlink does the switch when heat needed.

He said, I need an additinal relay which will control the pump and get the signal from the 2/3 terminals on heatlink.

He is coming back today or  tomorrow with the relay to install it.

This way the pump is not going to be connected directly to the heatlink, just to the additional relay.

Will come back once it is sorted.

Maybe here plumbers install heatlink and thermostats in general in a different way like in your country....or I don't know why does it works like this...

[Frustratedddd · Accepted solution]

Now I am confused! Which country are you from? Are you 240v ac in the house?

Can you confirm the voltage at terminals N & L

[Alcaza]

I am located in Romania.  It is 220V on N&L. Supposed to be 230V....

[Frustratedddd · Accepted solution]

OK, that's more or less the same as UK. Which proves my point with the voltage at terminal L&N, you should have 220v in your case, NOT 35v from your boiler!

[Alcaza]

I have:

220V on L&N,

35V on 2&3

220V on 5&6

😁

The electrician measured yesterday 

[Frustratedddd]

Well there is your answer, for some odd reason the plumber has installed 35v into terminal '2', for switching the boiler.

Could I ask you just to confirm what the wording is just above terminals 1-2-3 on your Heat Link? No need to remove your cover, just look at the picture above!!!

That makes things very odd in deed, as you now have a 5 core cable with mixed voltages in!

[Alcaza]

I don't know how supposed to be connected heatlink with this boiler ...  or why did it this way....

[Frustratedddd]

Totally understand where you are coming from, and you have paid good money to have the work done. You would in that case expect to have a good standard of work completed, but really?

Here in the UK that would not be allowed, as it fails the electrical regulations. I would suggest the least you ask the electrician to label the 35v as NOT 240v in the Heat Link. Otherwise that's just asking for problems in the future.

Pity, as such a simple installation has been made very difficult, I wish you luck.

I will ask anyone here on the forum that reads this, please give your comments if you have seen this type of installation before.

[Alcaza]

Hello,

It was sorted by the electrician,  he connected 2 wires 220V to terminal 2&3 and connected it to a relay, the pump is also connected to that relay. Now when the thermostat is asking for heat, the pump is starting same time like the boiler. The two relays ( 1 relays for upstairs 1 relay for downstairs ) + labour cost me £18 + £51. I will attach picture of the plan and the relay, maybe can help someone in future with similar issues.   

Thanks for your help anyway!

[Frustratedddd]

Exactly, 220v at terminals 2 & 3!!

You didn't need the relays as they are inside the Heat Link, and I'm sure the pumps together certainly do not take 3 amps,  which those relays will cope with. Like I said, from the very start, terms 2 & 3 are the switching for your heating and all you need is a 240v connection from those terminals!

I have attached an image showing the terminal relay amperage, as found in your handbook.

The main thing if you are pleased, job sorted.

[Frustratedddd]