Alpha ETec33 boiler with Hive or Nest?

3 May 2009
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United Kingdom
Replaced my boiler with an Alpha ETec33, with the EasyStat wireless controller. Thinking of replacing with a Hive or Nest controller, whitener the ideal thermostat is wireless, no wired interface with the boiler, is it possible to connect a Hive or Nest smart controller to these?
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Excellent... How?.. there is no thermostat I can take off and replace with either?
Of the two, I'd go for Nest. It's OpenTherm compatible, as is your boiler, so it'll help with efficiency much more than a dumb on/off Hive would. The Honeywell T6 is also worth looking at
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I would go with Nest from the two. More refined and nicer interface. Honeywell T6 will be cheaper, but nowhere near as nice as nest and software used to play up on mine. No problems since I changed it to Nest
But, I am still not sure how the Nest or Hive, or whichever, wouod interface with my boiler??
The receiver unit would be wired into the boiler, and the user interface would go on a table stand if you've not got any existing thermostat wires to power it with
With these I use the wiring on the existing receiver that is built into the boiler, and take a cable to the Nest or Hive receiver, if you dont do this you will have to link out the existing on board receiver
Thanks Ian, is there a standard connector for that, or does this require modding/connecting/soldering wires to the boiler?
no need to solder anything,if you have crimping set then crimp male spades onto the wires if not just cut the existing wires and use common terminal block, the connections are obvious L to L , N to N and the other two wires to Com and NO on which device you choose, if you come back and say which one you have chosen I will give you numbers etc of which terminals on your device, but it will tell you what Com and NO are
Thanks Ian, since I currently don't have any wiring for a thermostat, would I need to trying cable to a suitable location for the nest?, Or the main nest thermostat can be keep anywhere.

If cable is needed, would be 23 AWG cat6a network cable do?
Thanks for all the help Ian, attaching pictures of the Alpha smartstat - to be honest, feels quote cheap and toyish!!!

Q1: Do I really gain anything from replacing this with a Nest - tbh, I've already ordered it so, its kind of a moot.question - physically, the Nest is a damn sight prettier!!.

Q2: Does Nest have remote thermostats that it can be linked with, i saw some posts on the internet which suggest you can add per room thermostats, but the doesnt list any. I ask cos, it would be much easier for me to install rhe nest unit in the kitchen on the outside of the tall cabinet the boiler is installed behind.

Again, thanks for your patience.- I grew Asia, where constant sun means a boiler is.something you boil eggs in!!


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yes the nest comes in two parts, the receiver is hard wired to the boiler and is fitted next to the boiler, the actuall thermostat can go anywhere really, but will have to go near a socket as you have to plug it in to power it, it is possible to power the thermostat via the receiver but as you dont have existing thermostat cableing, then not really feasable, yes it is possible to have more than one thermostat but this involves a lot more complex wiring and plumbing and zone valves,there are some smart TRVs around I will attach a link for you to have a look at what these are, the best flex to use to wire the nest receiver is 0.75mm2 either 4 core or 5 core, you can buy it by the metre and you would only need 1M of it.
  1. So, with all the help around... Thanks Ian, I got a bit adventurousand opened up the boiler's front panel ( a first in my 2 score n 5 yrs!!!)...found it has nicely labelled connectors, including 2 for OpenTherm (see attached).

YouTube showed me the Heatlink has cnnxtors for opentherm as well..Ive been looking at nest for close to 2 yrs, but have only ever see the Apple-esque thermostat, wasnt wven aware there is a heatlink in the equation (which is why I was asking if I could run network cAble from the boiler to the Nest).

My Alpha combi"s manual has the following rather succinct instructions:

Open Therm type installation
Note: Before purchasing / installing Open Therm type controls from an alternative manufacturer, it is the installers
responsibility to ensure they are compatible with the Alpha boiler.
Remove the control panel as described in Section 5.10, if it has not already been removed.
Refer to controls manufacturer's installation instructions for specific mounting / fitting guidance.
Route the BUS communication wires along the groove in the control panel to the terminal block connections 41 and 44 (the
wires can be connected either way round).
Ensure the link wire between terminals 1 and 2 remains in place.
Replace the control panel cover in reverse order.
Note: Refer to parameter P7 (see Section 6.13) to select the correct parameter to allow the boiler to operate with alternative
control type '1'.

I think Im getting the hang of it now. With OpenTherm, Iunderstand it controls both water and CH, do I need to unloop anything, or just.connext the corresponding wires inckuding no 41 and 44?.

Thanks again.



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Hi Ian, finally got connecting the Nest. My plumber is getting a bit stumped. Attaching pics, can you please advise which cables.go where?


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