I'm new to Hubitat and this is my first post. I've been quite happy with the system and have several switches, plugs, relays and sensors working well.
This home is located in a very cold climate area and the home heat is provided by a Prestige AVC Prestige Solo gas boiler. If we are away for an extended period of time in the winter and there is power recycle I would like to have a way to remotely hit the power button on the boiler to get it going again. There is a real risk of the indoor pipes freezing if we cannot fire it back up.
I have not been able to find anything from ACV to enable remote operation or auto start.
I've looked at the popular remote button pushers (e.g. SwitchBot, MicroBot) but I do not believe they will be strong enough to reliably push the on/off button on the boiler. It's a pretty big button that offers a lot of resistance. But I haven't tested this.
I also don't want to do anything to void the boiler warranty so getting inside and adding a relay is probably a no-go...well that's probably beyond my expertise anyway if I'm being honest.
Here is an image of the boiler's control panel. The on/off button is the large one on the right of course:
The first thing that came to my mind is a Bell Crank.
The small motion and power of a SwitchBot can be 'magnified' by the correct application of a Bell Crank. The 'classic' bell crank is L shaped. A pivot is at the joint and as you move one end of the L the other end moves, but in the opposite direction. The length of the legs determines the magnification of force or distance. It's all ratios, so you can't get both large motion AND large power from a single bell crank. Think of bicycle hand brakes, a large squeeze of the handle causes a powerful pinch of the pads.
Personally I'd just use a solenoid since I could get more power and thus convert into larger travel. The hard part is not the switch movement if I used a solenoid, but the remote controlling. SwitchBot solves the remote control, but not the power/throw.
My idea would be to mount the shutoff's body positioned so that the lever arm would
swipe the button as it closed. Maybe add a piece of rubber hose to the end of the lever arm to add some flex as it passed over the button.
I absolutely love this challenge, and this is right up my alley (+1 for the bell crank for the purpose of adding leverage) but, were it me, I'd replace that [@#$%^&] button, or look to add another in parallel somehow. Saw your warranty mention.
what about a threaded shaft on a switched motor? that provides lots of linear pushing force.
If you're handy with gearboxes, yes. But I also worry about holding the button depressed too long or hitting it too hard with a linear actuator.
I like the Dome unit because the lever arm is ready-to-go but getting the right mount to give you the right 'sweep' in a 1/4-turn is going to take some fabricating & tinkering.
Here is a 12v valve that I have experimented with on HE, but it just has a half-round shaft after the valve body is removed, so some sort of lever arm or gearbox would be required. It has pretty good torque.
Are you sure the boiler behaves this way in a controlled shutdown, like if the breaker was turned off for thirty seconds and then back on again? Maybe if your experience has been with power outages or momentaries, there could be something them that cause this behavior. Maybe you could plug in your boiler to a zwave or zigbee outlet and cycle it for thirty seconds, and it would come back to life without pushing the button. Ideally.
Hey @Velvetfoot, thanks for the reply. I did do a breaker test just now and it did come back on... fully. This is great of course, but unexpected. We have had occasion to have a neighbor come over while we were away and hit the power button for us. It had something to do with a power interruption, but perhaps something else is going on. I'll call Triangle on Monday to see if they have any thoughts. Thanks for suggesting I should validate this.
I actually was searching the web and found an hvac guy who mentioned the 30 seconds off and on thing. You could make a rule where the boiler power gets cycled if the temperature in the house gets below a certain temperature. Sends you messages, etc. That's getting close to depending on Hubitat for mission critical stuff, which I've been reluctant to do, but getting closer.
