Window switch wired to HR92

[Garth]

Hi
I was minded to fit a window contact HCA30 to my bathroom window so as to ensure the heat in the room is off when the window is open. I would need cable ACS90 as well. This sounds easy. However, after registering on the Resideo website and attempting to purchase the HCA30 window contact, I discover they do not supply this any more! Well done, Resideo! I wondered whether they have abandoned this feature.

I thought I would buy elsewhere. I discovered that is not easy. The best option - a foreign supplier - involved pricy items plus postage costs making me think twice about the project.

I can purchase a cable cheaply from a number of sources - and further choose whatever length I need. (mini usb at one end, chop an unused fitting off the other end if appropriate.) A substitute for the window contact HCA30 is more problematic. There are lots of similar devices available, cheaply, intended for security purposes, mostly. Some are actually Resideo products!

These products seem to have batteries, and I presume I need something similar. But I have no information as to whether HCA30 has a battery, and what voltage etc. Worse, I don't know whether contacts "normally open" (or closed) means open or closed when the window is closed. Changeover would be ideal!

I may have to experiment, but I am confident I can put together something which will do the job at reasonable expense. First, of course, I would like to hear if forum members can help me. Thanks in advance!

[Richard]

The window contact is not normally needed because the Radiator Controllers have built-in window open detection (which on the HR92 can be switched OFF, AUTO or Cabled Operation on parameter 11).

I do have a ACS90 here but never seen a HCA30 in the 13 years I've been doing evohome. I've just tried plugging the ACS90 in (its just a USB Micro C connector) and adjusting parameter 11 to wired contact and as per the instructions.

Having the wires open circuit brings window open function ON and touching the green wire and the white wire with black stripe together turns window function OFF. I'm assuming the HCA30 is simply a reed switch and magnet, similar to most wired alarm system contacts.

I don't have the USB pinout, but hope that helps you somewhat.