I have a dumb boiler which has a simple timed controller on it. The boiler has gravity fed hot water and pump fed radiators. The hot water has a simple tank stat that switches a zone valve to closed when the water is hot enough, the radiators are on a timer.
My idea is to replace the controller with a smart relay so I can sense the temperature in certain rooms and have it switch the boiler and pump on and off. There would be a timed schedule so it wasn’t coming on during the night unless the temperature dropped dramatically. I would also like to somehow sense when the hot water zone valve is closed so I can switch the boiler off.
My thoughts are to use a Sonoff 4CHPro R3 relay to switch the boiler, pump and zone valve and have Aqara zigbee Temperature and Humidity sensors around the house.
So the advice I’m looking for is whether the Sonoff 4CHPro is suitable for this project and also is there a smart device that I can use to detect when the zone valve closes. The Zone valve has a 240V output that I could use if I can find a device that when it has 240V applied shows up in HA as on or activated. I could then use this as a trigger to switch the boiler off.
Any other ideas are welcome. I did read some other posts but I cant see how they would work with my specific setup.
I’m very interested in making my boiler smart too. I have a hot water system with 5 circulators and indirect hot water heater. Been trying to figure a low impact telemetry solution for it for years. Just be aware, you really don’t want to control the actual boiler going on and off because there are high and low temperature limits and other safeties built in as well as on more modern boilers algorithm based controllers that optimize efficiency. Maybe you already know about all that but I just wanted to throw it out there.
I have thought about
Adding inductor based current sensors to the zone control or connection boxes on the 110v circulators
Using optocouplers to detect the zone status lights going on and off
Using machine vision with a camera to check lights and displays on the controls
Using heat sensors on the pipes right above the circulators to detect indirectly when they go on and off
Best I’ve been able to do so far is a yolink vibration sensor sitting on the burner head to tell when it goes on and off- works well but only accurate to the nearest 60 seconds and not sensitive enough to detect the pumps running.
I think there’s a large opportunity out there for someone to create a ul listed smart control that natively interfaces to a smart home infrastructure. There’s none that exist that I know of.
Only other thing is I do have a smart WiFi gauge on my oil tank.
Yes, for sure, after seeing the aftermath of an industrial boiler explosion….use a dedicated boiler controller.
In my system I can sense the burner being on by using a CT sensor around the 110v line feeding the burner. I placed it inside the electrical box and run it out to a modbus ethernet analog input module. I’m able to scan it every 3 seconds.
I also had success putting a CT sensor around the 24vac thermostat loop to the indirect hot water tank. The current is very low, like 0.001 amps but it senses it. I also put a normally closed relay in series on the indirect hot water so I can turn off from HASS when I’m away.
My other heating zones are controlled by smart thermostats. I do zone coordination in HASS, so if one zone comes on, and another zone is almost ready for heat that zone will come on also. This minimizes boiler cycles. Can provide more details if needed.
I totally understand this, the issue I face is that the boiler is run by a fairly dumb controller and the boilier itself has its own thermostat to turn it off when it gets too hot. I wasn’t looking to replace that. The reason for trying to replace the dumb controller is it is set by a time schedule and currently can only turn off with the time. Therefore if the radiators are at temperature the pump doesn’t run and if the water is hot it just closes the zone valve. The boiler itself comes on and off based on its own thermostat, so it keeps heating up even though the rads and the water are hot. I’d like to be able to make the controller stop the boiler firing unless it needs heat to the rads or hot water is needed.
It’s an old boiler that is serviced every year and does the job well.
Boilers need to maintain a minimum temperature. So they will fire periodically to do that. This is by design. If the boiler cools down too much and then heats up this causes thermal stress to the metal that overtime will cause the boiler to crack.