FItting Room Thermostat

[stephenjehart]

Hey guys I hpe someone out there can help. I have bought a Horstmann HRT4-ZW wireless Room Thermostat to fit a temperature control to my Valliant EcoTec Plus 824 combi-boiler.

I have wired the Thermostat receiver into the mains and then run the folowing connections:
Receiver - Boiler
2 - 3
3 - 4
4 - 5

The boiler is showing the error code S30 (3 and 4 not bridged). THe receiver and controller are correctly paired and the controller is asking for power and the receiver is switching to demand from the boiler - but the boiler is not responding to the demand.Any support would be gratefully received.

Regards

Steve

 

[simond]

2 and 4 are the only connections you should have used on the Horstmann switch side.

They should go to 3 and 4 of the boiler.

5 on the boiler is a neutral so you would have put a dead short through the boiler and radio receiver, if you had attempted to turn it on.

Don't be surprised if you have burnt out one or both of them.

 

[stephenjehart]

Simon,
Thank you so much for your time. I have used up the couple of spare 3A fuses I had and have also removed the Xmas tree lights fues, and the magimax fuse before your answer identified the problem.
Problem resolved and everything would appear to be working... apart from the lights and magimix!

Steve

 

[stephenjehart]

Small hitch. I have wired 2 to 3 and 4 to 4. The reciever and the thermostat unit are correctly communicating and I can see that the reciever is moving from on to off as the temperature of the thermostat rises. However there is still a challenge in the communication between the reciever and the boiler as the boiler does not turn off when teh reciever tells it to.
I assume the connections are wrong in some way. Does 4 go to 2 and 3 to 4 or something?

Any ideas anyone?

 

[simond]

In all probability you have fried the Horstmann receiver, when you had boiler terminal 5 connected, it puts a short straight across it.

A short circuit across the contacts tends to weld the relay on, could be 100s of amps for that moment before the fuse blows.

To check, remove one of the wires from either 3 or 4 in the boiler (elecs off first of course) the boiler should stop.

 

[simond]

Should add that you will need to buy another one.

 

[stephenjehart]

I have just bought a new one. Only 11 months later! Slightly different Horstmass receiver. THe back looks like this:

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• stephenjehart
• 30 Oct 2011
• 2

THe wiring diagrams in the booklet like this:

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• stephenjehart
• 30 Oct 2011
• 2

ANd the connectors inside the boiler like this:

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• stephenjehart
• 30 Oct 2011
• 1

Any advice on what wires to where would be much appreciated. In particular where to plug in the 230v live from the fused supply, and where the wires that go to the boiler connectors 3&4 come from.

As always advice very much appreciated.

 

[jackthom]

If you remove the boiler link wire betwen 3 & 4 and then check which of the two is the permanent live. That goes to the "L in" connector on the receiver.

The remaining one (3 or 4) goes to SL(on), on the receiver.

Not forgetting to connect the marked Live & neutral feeds for the receiver.

 

[stephenjehart]

Jackthom - thank you so much for taking the time to reply. Really is much appreciated. As you can see from teh thread above I am keen not to fry anything by charging forward without being certain.
The boiler instalation instructions are:

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• stephenjehart
• 30 Oct 2011
• 2

THis make it clear (to my brain at least...) that 4 is the live terminal on the boiler.
Therefore the action I am going to take are:
Isolate the power to the boiler.
Remove the red bridging wire on the back of the receiver to enable "volt free application".
Remove the bridge wire in the boiler between 3 & 4 temrinals.
Wire the receiver to the fused supply with the live to the bottom right "L", and the neutral to the bottom centre "N" terminal.
Wire terminal 4 in the boiler to the tope centre "L.IN", and terminal 3 to the top right "SL(on)" terminal.
Cross fingers and turn the power back on.

robably a bite late to think about this, but I assume this is only going to impact on the heating and not the hot water?

 

[jackthom]

That sounds good.

Because you are removing the wire link in the receiver, in this type of basic thermostat use it no longer matters whether 3 or 4 in the boiler is the Live feed, it will work either way round.

As it's a combi boiler the hot water should be unaffected by this.

 

[stephenjehart]

All sorted. Thanks to Jackthom and Dan_Robinson for your help. Only took 11 months, 2 x Room Stats and 1/2 dozen fuses. There might be a lesson there about getting a professional in first time round...

Thanks for your help.

 

[Dan Robinson]

Glad you're sorted.