controlling air conditioning systems

[mozzo12]

Anyone tried to apply eveohome to control air conditioning. My thought is to use the normally closed contact of the BDR91 relay to control the activation and de-activation of the air con system. For example lets say I want the air con to maintain 25 degrees. I set the evohome to 25 degrees in the normal way. With the room temp above 25 degrees the BDR91 is off but NC contact is closed hence 230v present and the air con system is activated. When the room temp falls below 25degrees evohome activates the BDR91 but because the air con is connected to the NC contact the contact would be opened and the air con would be turned off. Naturally Evohome was not designed for air con and if evohone was turned off the air con would be on permamently but that is nit a problem for the system I am looking to integrate evohome into as the system has its own internal min and max settings that would stop it being on 24/7 non stop. Any thoughts anyone.

[Richard]

evohome wasn't designed for air con and won't really work properly, as you want reverse logic TPI to happen than normal... Wiring a zone relay on the normally closed contact would mean when the evohome system is turned 'off' the air con would be on. It would work ok to a degree just not very well imho.

[mozzo12]

Thanks for your reply and I understand and know it was not designed for that purpose and there will be limitations and maybe not as precise operation and non support from Honeywell or 3rd party providers. However as you have confirmed the presence of the NC contact does mean it can work and therefore provide remote sophisticated control to an otherwise un-sophisticated system. I was also enquiring to ascertain if anyone had actually implemented such a method. I was planning to brief the client on the reality/design specification and limitation and they accept to move forward or not to try this solution with accepted risk.
I was never planning to sell the solution as tried and tested and approved by Honeywell but in absent of no sophisticated control for remote management within a holiday rental in Spain Evohome may be a best option albeit with limitations.