Honeywell T45/ST699 to Hive 2 wiring

That existing stat can't possibly be working (or working correctly) as there is no live supply to the electronics or the common on the switch.
 
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Is it not switching 230v from the boiler via the SLs and neutral?
No.

The existing thermostat has L and N terminals for a permanent 240V supply, this is required to power the receivers internals electronics. The manufacturers provide a link wire from the live terminal to the common of the output relay if it is being used to switch on a mains controlled combi boiler or zone valve. The valve or boilers control is connected to SL on. SL off is almost never used, and is used for valves that need power to close them as well as some other much less common wiring configurations.

As the receiver is wired now there is no live connection to power the receiver, unless the brown wire is live in which case when the stat is off it will get a supply through the relays normally closed contact to the common and through the red link wire to the stats L terminal. However when the stat calls for heat the relay will change over and cut the supply to the electronics causing it to immediately switch off again, this will re power the stat and would cycle on and off continuously.

If by some bizarre configuration your existing stat is working correctly the Hive will not work wired in this way.
I would recommend calling an electrician to fit the Hive, but what type of boiler/heating system do you have?
 
Thanks Echo,

The old wireless stat worked fine which is what confuses me.

The boiler is a Baxi 30HE.

I measured voltage on the old receiver terminals and the found the brown SLoff was 230v and SLon was 50v.

I've attached a pic of the boiler wiring for your info.


Mike
 

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That brown wire should be in one of the terminals with the red link, but anyway.

Replace the 4 core flex with 5 core flex. I take it you have the single channel heating only Hive?

On boiler
Brown to L
Blue to N
Green/yellow to E
Grey (fitted with brown sleeve) to 1
Black (fitted with brown sleeve) to 2

On Hive
Blue to N
Brown to L
Grey (fitted with brown sleeve) to 1 (common)
Black (fitted with brown sleeve) to 3 (heating on)
Green/yellow to Earth tether.

If the boiler has a built in heating timer, set it to always on. The plumbers will probably tell you off for removing the casing off of a gas appliance.
 
Thanks!

Just to confuse matters I have a dual channel Hive as we will be going unvented at some point :whistle:


Mike
 
In that case the wiring is different as the 2 units aren't the same.
For the 2 channel version
Keep your existing 4 core flex.
At Hive:
Grey (with blue sleeve) to N
Brown to L
Black (with brown sleeve) to 4 (heating on)
Set boiler timer/controls if fitted to heating always on or the Hive will have no power.
The wiring will require total reconfiguration when a hot water cylinder is added.
 

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