Two Hive Thermostats 1 Boiler

18 Dec 2022
Reaction score
United Kingdom
Hi Everyone, I'm new here and dealing with a very bespoke system so please be gentle.

Basically there are two zones in the house. Upstairs (with hot water) and downstairs.

Originally the zones were controlled by two Horstmann H17 XL with separate thermostats in each zone.

So far I have done the following:

Installed one single channel hive on the downstairs zone (just heating).
Installed one dual channel hive on the upstairs zone with hot water.

At the moment I have just bridged the old thermostats as the connections in the wiring box are just too complicated for me to bridge in the box and I needed a quick solution as the heating has not been working.

The issue am I am facing is that the boiler simply doesn't turn on, it is a pellet system, however I have managed to get it working but it switches off and says "stopped by external contact". The pumps all work and the system appears to be working, just without the boiler.

I've attached images of the wiring in the main panel and have followed the normal installation for the Hives.

If someone could look and give me a steer as to where this is all going wrong I would appreciate it.

If I have missed anything just shout and I'll post more images.

Thanks in advance!!


  • PXL_20221217_161206727.jpg
    238.3 KB · Views: 39
  • PXL_20221217_175447909.jpg
    400.6 KB · Views: 40
  • PXL_20221218_111321701.jpg
    353 KB · Views: 40
  • PXL_20221217_153919089.jpg
    249.4 KB · Views: 65
Sponsored Links
Looking at picture 3 it seems likely you have three motorised valves, so basic system is the three thermostats connect to the three motorised valves, and the valves once open work the boiler.

Diagram shows orange connects to boiler, and brown connects to thermostat, blue neutral, and grey to permanent line. The thing is the motorised valve comes with cable so one can go by colours, note some times instead of brown you get white.

So you should be able to identify the motorised valve cable and test the browns or whites are becoming line when thermostat is switched on.
Thanks ericmark, that's really helpful.

Based on the shocking wiring in the control box, I'm going to buy a new one and rewire the whole thing again into a better panel and label the wires with their output/input and what they control.

Once that's done I should be able to see the configuration better and make amendments to the controls easier.
I really can't work out why homes split the heating into two zones? OK with my home flat and main house yes, as most of the time no heating in flat, but we use the main house 10 heated areas very diffrent. Shower room, bathroom, hall/landing always heated, kitchen for when cooking evening meal, the dinning room and office rarely heated, as we eat in living room, the living room most of the day, bedrooms most of the night, and craft room a few times a week.

I have one room no control, the bathroom, the shower room/toilet a mechanical TRV, other 9 radiators, two in one room, all have programmable TRV heads, flat a further 4 mechanical TRV's so in real terms around 14 zones.

So one Hive wall thermostat in most homes is enough, as Hive TRV heads link to it, since Hive heads are expensive, would only fit in key rooms, the eQ-3 or Terrier i30 are still programmable but much cheaper.

If going to rewire do you really need two independent zone valves? just link grey for up and down and work together.

It may not work for you, but now is time to think about it.
Sponsored Links
I don't use the hive system now but not got round to removing it.
This was a combi with 2 heating zones.


  • imageedit_0_9779473484.jpg
    106.9 KB · Views: 30

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local