Installing an OpenTherm boiler control / thermostat - Gas Safe?

[Stevos]

My heating engineer is going to install a new combi boiler for me (Ideal Logic 2 Max), which I think he will fit with a standard thermostat / control.

This boiler seems to support OpenTherm, and I'm wondering about fitting a smart thermostat and radiator valves at a later date to improve efficiency and save money when cash flow permits. It seems OpenTherm connection requires a very simple wiring connection, and I'm fairly comfortable with wiring and electrical safety.

What I'm not clear about is whether the fitting process would involve needing to open the boiler in such a way that it would require a Gas Safe engineer to complete.

Am I right in thinking that I officially have to pay an expensive engineer to connect two wires, or has boiler design progressed to the stage where electrical interfaces are cleanly segregated from dangerous gas work?

 

[muggles]

Why not just ask the person installing your boiler to fit the control you want?

 

[Stevos]

A reasonable question, but I don't have it yet - and cash flow is not great at the moment - I'm planning for the future

Edit:

The replacement boiler and installation costs are significant and weren't a planned for expense. Additionally I'd like to get a baseline for how the system performs before adding smarter controls.

 

[muggles]

Fair enough. The Logic isn't a great boiler but I suppose you might be committed to that now. As for the stat installation, yes it is necessary to access the room sealed chamber in order to alter the wiring. Your installer could fit an OpenTherm stat for you now though, then you could change it if desired at a later date. The EPH Combi Pack 4 is an excellent wireless OT programmable stat available for about £60, and it can even be turned into an Internet-connected stat at a later date using their Ember smart hub. If you need a wired one then that version is about £35

 

[oldbutnotdead]

Opentherm connection is via a bit of 2 core cable. Just get your installer to connect a length of 2 core from the Opentherm connection to somewhere suitable, remove the internal link across that pair and link the ends of the 2 core.

 

[martygturner]

Fair enough. The Logic isn't a great boiler but I suppose you might be committed to that now. As for the stat installation, yes it is necessary to access the room sealed chamber in order to alter the wiring. Your installer could fit an OpenTherm stat for you now though, then you could change it if desired at a later date. The EPH Combi Pack 4 is an excellent wireless OT programmable stat available for about £60, and it can even be turned into an Internet-connected stat at a later date using their Ember smart hub. If you need a wired one then that version is about £35

Errr no you do not need to access the room sealed chamber on the logic, the wiring centre just swings down, remove the plastic front panel two screws and two clips then the control wiring swings down.
see https://mail.idealboilers.com/uploa...-combi-2-installation-and-servicing-guide.pdf pg27

 

[Deleted member 267285]

Errr no you do not need to access the room sealed chamber on the logic,

Perhaps @muggles might have worded it different. Access to the wiring is via removing the front cover as per your link, that front cover forms part of the combustion circuit, which is what makes it room sealed.

 

[muggles]

Errr no you do not need to access the room sealed chamber on the logic, the wiring centre just swings down, remove the plastic front panel two screws and two clips then the control wiring swings down.
see https://mail.idealboilers.com/uploa...-combi-2-installation-and-servicing-guide.pdf pg27

You've contradicted yourself. The plastic front panel is what forms the room seal on this boiler. Removing it = accessing the room sealed chamber. That's why it says in two different places in the manual you've linked to "Do not operate the boiler if the front panel is not fitted."

 

[martygturner]

the front panel that covers the wiring center is not part of the sealed chamber...have a quick look at the drawing....its part of the lower assembly that covers the pump and inlets...which is not sealed.....by the way.

 

[muggles]

the front panel that covers the wiring center is not part of the sealed chamber...have a quick look at the drawing....its part of the lower assembly that covers the pump and inlets...which is not sealed.....by the way.

I thought I'd just double check in case the Logic2 design has been modified from the original Logic design, but no it hasn't and you're still wrong.

At 1:13 you clearly see the front cover being removed in order to access the wiring centre. There is no access to the wiring centre without removing the front cover. The front cover forms the room seal.

 

[Deleted member 267285]

the front panel that covers the wiring center is not part of the sealed chamber...have a quick look at the drawing....its part of the lower assembly that covers the pump and inlets...which is not sealed.....by the way.

I think you’re possibly getting confused with the combustion chamber, but no wiring would be located in there.

 

[harrythefurrysquid]

the wiring centre just swings down, remove the plastic front panel two screws and two clips then the control wiring swings down.
see https://mail.idealboilers.com/uploa...-combi-2-installation-and-servicing-guide.pdf pg27

@Stevos this answers your question.
You theoretically shouldn't, but you can and it's easy - you now have both a video and detailed instructions on how to do it.

I'm absolutely not a plumber - just a customer who also needed Opentherm (albeit on a WB Greenstar) so I have no qualms in saying JFDI. Opentherm works fantastically well and you should enable it when you can. I'd also recommend Drayton Wiser if you can afford it - I'm very happy with my installation.

 

[Stevos]

Thanks to everyone for the helpful and clear advice, as well as links and video. I think both the regulatory and practical aspects should now be clear to anyone in this situation.

As an aside, it seems mad (especially in these days of smart thermostats being marketed directly to end-users as part of smart home automation) - that modern boilers still require opening to get to the electrical interface. You'd think there would be a separate flap or panel (or even an industry standard socket, plug and cable)

I appreciate boilers are aimed at the qualified installer market, but it's a shame the stuff that should be user-servicable is handled this way.

I suspect this is the underlying reason behind the chaos with Tado removing OpenTherm support, and then haphazardly adding it back for some units

 

[ianmcd]

the front panel that covers the wiring center is not part of the sealed chamber...have a quick look at the drawing....its part of the lower assembly that covers the pump and inlets...which is not sealed.....by the way.

you are still wrong, the front cover has to be removed to swing the controls housing down, the front cover IS the combustion seal

 

[DP]

the front panel that covers the wiring center is not part of the sealed chamber...have a quick look at the drawing....its part of the lower assembly that covers the pump and inlets...which is not sealed.....by the way.

Once the front cover is off, the combustion chamber is revealed.
Also there is a need to ensure the seal is maintained Once the front panel is back in place. Those that work with 5his boiler will know what I am talking about as wiring once in place needs to ensure sealed chamber remains sealed.