Honeywell ST699 to Hive system(Failed to work)

[dbhuwad72]

I am new to this forum and wish to know what I could do to rectify an issue with the wiring of my current system. Although it is been said that the wiring could be correct depending on how it is connected to the boiler and the wiring upstairs near the water tank. There is another wiring box with additional wires going into that white box.
Here are some photos to illustrate what I currently have. An attempt was made a few weeks ago to install a Hive system but was not working correctly. My guess is that the Hive system was confused with the wiring setup and I connected the wiring correctly on the Hive, meaning neutral to N and Live to L. My question is an impossible one as the live is connected into the neutral and neutral connected to the live. Although the system is working absolutely fine for over 20 years. Previous post suggested getting multi meter and checking for polarity, voltage etc. The guys were helpful as I mistakingly hijacked someone else's post, so created my own finally.

 

[stem]

I assume that the system is working at the moment and you have reinstated the Honeywell ST699. So, from that position:

First of all, before doing anything else. There seems to be an issue here that needs resolving.

Usually a blue wire is used for the neutral, and brown is a live. These appear to be transposed. So first, someone who can use a multimeter correctly should check what they actually are. If they are transposed. It would appear to be only the ST699 effected as the brown wire is still linked to the switching terminals. With the Hive the links are made internally so the L will have to go to the correct terminal otherwise the heating system won't work. Once this issue is resolved.

The wires at the Honeywell ST699 move to the Hive terminals that have exactly the same function. [Once the L & N issue has been resolved]

You don't need the loops that the ST has between L (or in your case N!), and its terminals 5 and 8. Hive has these connections internally already for you.

The old room thermostat can't simply be disconnected as this would leave the heating wiring 'open circuit' and the heating will not operate, so, the two live wires that are in terminals 1 and 3 should be connected together to complete the circuit.

This can be done where the thermostat is located, or at its origin by linking together the two terminals that the wires going to 1 and 3 originate, then the old thermostat cable can be disconnected completely.

 

[dbhuwad72]

Hi,

Firstly, the system is working fine after disconnecting the Hive system. Going forward I do not know what to do unless I get a decent non over rated and over priced central engineer to work out why these damn wires are wired in this fashion.

I really was hoping to rectify this problem myself with the help of these forums and hoping that I may stumble on someone who could figure why these two wires are connected that way!

I do appreciate your time and effort above and all makes sense.

Thanks Stem.

 

[dbhuwad72]

Hi Stem,

Just to add - I did not connect those two brown wires when I totally disconnected the thermostat as those wires were terminally disconnected when fitting the Hive system.
When I fitted the hive system with the wires going in the correct wiring diagram the receiver did come on and light up.

I am wondering if this may have caused some sort of issue when trying to get it up and running. I followed the instructions carefully but to no avail.

 

[stem]

If the L and N are transposed, and you kept them like that with the Hive, because Hive has the links made internally (instead of externally) it would be making a neutral available to the heating and hot water controls instead of a live, meaning nothing would work, but it shouldn't have done any harm.

A simple multimeter costs less than £10. By measuring between a known earth and a live would read approx. 230V, and a know earth and a neutral approx. 0V Do you not know anyone competent with a multimeter that could carry out the test for you.

Or would you be able to trace this wire back to know what it's connected to at its origin?

 

[dbhuwad72]

I have a multi meter that can test any voltage. I will run this test on those wires and see what reading I get from the brown and blue wire.