Hive v3 Active Heating install question(s) for heating and hot water - Worcester Greenstar 15i Syste

stuff.hunter

Hi everyone.

I have installed Hive 2-channel receiver in place of old EPH R27-HW 2 channel controller for Worcester Greenstar 15i System boiler (there were only 4 wires connected in wall box)

and Hive thermostat seems to control both heating and hot water ok (turns boiler on and off)

Now, the question is how to remove old EPH manual knob thermostat (or bypass it?) as "Heating on" light on it comes on and my guess is that might somehow affect temperature settings made on Hive?

Connection of old thermostat

would anyone have any experience with similar setup?

Any help deeply appreciated.

Thanks,

Kris

DublinDilbert

There must be some central location where all of the wiring from the room stat and EPH programmer are connected. Have you zone valves? Where are these wired to? Wiring centre?

Have you connected in the HIVE unit yet? From memory the order of the wires should look very similar to where the EPH 2 zone programmer was. But you need to check.

I wouldn't worry about by-passing the room stat yet, till you have the hive system working, for now just turn the room stat up to max/full/30C.

stuff.hunter

https://www.boards.ie/discussion/comment/122022510#Comment_122022510

there are 2 pumps (my guess)

junction box with controller wires (bunch with earth yellow green) and thermostat (earth chopped off) (both on the left)

Hive receiver plugged instead of EPH controller (the same terminals layout) and everything seem to work - it turns heating and hot water from receivers buttons, reacts to thermostat as it should and can be controlled from the app itself

thanks

stuff.hunter

added more info 😁 also, would Hive be cause of low pressure measured at boiler? Thanks

DublinDilbert

No Chance the hive is causing low pressure at the boiler.

That's good the hive is now functioning in place of the EPH controller. So all you need now is to by-pass or disconnect the old room stat that is current turned to max…

You need to check the wiring diagram for the room-stat, but at a guess joining the black and brown wires together will by-pass this. but it would be better to disconnect it at the other end of the cable and put a loop in there. I would imagine the 4 core cable on the LHS (with earth cut) is going to the room stat, but hard to tell. You will need to pull out the cable at the room stat end, you could always bell along the disconnected earth wire to see if they are the same cable.

stuff.hunter

@DublinDilbert

Thanks for your help!

The red arrow on the pic below marks thermostat bunch, green controller and its wiring on the second pic.

About joining wires, do you mean black and brown on thermostat itself?

thanks again

DublinDilbert

Yea it looks like :

1. black output from the controller → brown to the thermostat
2. black output from the thermostat → black wire going to a zone valve etc…

You need to power down everything and check that there is no power on. Cut the black and brown going to the thermostat and join A → B in one of the spare connectors. Or link the two connections shown in blue, which is effectively the same thing. I would also cut the neutral going to the thermostat so it is completely disconnected.