Despite manufacturer warnings about voiding the warranty, everyone using the Honeywell R8845U-1003 or similar relay switches to WiFi stat control millivolt heaters and furnaces is reporting complete satisfaction -- it works, no question! What about an electronic ignition wall furnace like the Williams 1773512? It comes with a built-in stat. Can it simply be disabled and the wires reconnected to a relay switch? Seems to me that it should work just the same as a Rinnai NG wall furnace. It has an electronic ignition and can be connected to a Nest, Ecobee, etc. via their accessory relay switch. So what about it?