The Efficient Home Forum

Hi There

i have ordered my evohome system and have assumed the compatibility of the Intergas HRE OV. Can you confirm this system will be compatible with this boiler and the standard gravity fed CH and hotwater system?

i also wondered what you are supposed to do with the existing old turn dial thermostat once the system has been installed? do you just turn it up to the max position or remove it?

The Intergas HRE is compatible with evohome, although we are told that there are some issues with the OpenTherm protocol when using evohome with multiple zones and the HRE (but this is an Intergas issue).

Why are you staying with gravity hot water?

My understanding is that due to the size of the house a combi boiler would struggle to cope or end up being overly expensive. That and I just couldn't handle showering without the pump pressure. I have had very poor experiences showering in places with combi boilers. No idea if this is justified criticism or not just my experience.

Do you need to use the r8810 opentherm bridge for the system to work with the HRE or is it only required if you want to use the variable demand features of it?

R8810 OpenTherm Bridge is required if you want OpenTherm control. I think the TPI/weather compensation combination also works well.

Hi there I am trying to fit the bdr91 to my existing S plan ch and hot water heating system with a danfoss fp 50 connected to an ideal classic boiler. I'm a bit lost as the instructions are vague to say the least. I will be getting a new intergas boiler installed but wanted to get things set up beforehand minus the opentherm. Can you tell me where to start? Junction box upstairs with the supply for the pump and valves?

Junction box is danfoss wb12

I would appreciate any assistance as I can't figure it out at the moment.

Basic S Plan wiring diagram is on Page 46 of the evohome Installation Guide. What are you struggling with?

I'm all good now was about to start taking apart and rewiring my ch junction box but once I understood properly how the wiring worked I just connected the bdr 91 to the three existing wall thermostat wires with boiler controller set to permanent on (not ideal but simple and works). N-n l-l link l2-a and yellow ch wire to B. All seems to be working perfectly now. No idea how I got so confused when it was actually so straight forward. I assume the bdr91 relay for the hot water can be looped into the controller circuit the same way just take a live neutral and hw feed from the existing controller and leave that set to permanent on letting the bdr91 open and close the circuit? Much simpler than trying to work out the junction box wiring as all the colour coding is a bit artistic to say the least.

A lot of good posts elsewhere with photos of the install and various ways of doing it if you hunt around.

When the new boiler is installed and the opentherm module wired In will it replace both bdr91's or just the CH one?

Have a look at this post - https://theevohomeshop.co.uk/forum/view ... ?f=5&t=211