Creating a renewable heating source, an outdoor wood boiler or furnace presents a variation on the classic wood stove. The setup includes wood burned inside a firebox, with a âwater jacket,â or chamber or water, surrounding. An exhaust heat reclaiming system assists in controlling the temperature.
How an Outdoor Wood Boiler Works
To keep a property warm, heated water in the boiler’s chamber gets pumped on a 24-hour loop, where it passes through insulated, underground pipes. Should there be the need to heat multiple buildings, a series of pumps help the water travel a greater distance or through different pathways.
But as is the case with any heater, the potential for the system to become too hot exists. Ideally, an outdoor wood boiler maintains a temperature between 160° and 180° F, controlled by both the fire and exhaust system. Once the furnace reaches 180° F, the fan giving air to the fire turns off and closes the damper, which in turn lessens the flames and temporarily prevents the wood from burning further.
Additionally, so the building isnât receiving too much heat, any water leaving the tank goes through a mixing valve, which ensures it remains at a safe temperature.
What Does a Water Control Sensor Do?
However, while the system knows not to get above 180° F, it still allows for temperature control, through a thermostat and automatic draft control. More sophisticated systems may further incorporate computer controls, which direct the air toward the fire at a variable volume.
Hereâs where the water control sensor comes in. Between keeping your home at the desired temperature and ensuring the boiler doesnât overheat, it monitors how hot the water gets and keeps the fire under control. Otherwise, scalding hot water could end up passing through your pipes.
Whether youâre an HVAC technician repairing one of these outdoor boilers or someone attempting to understand how your facilityâs heating system works, the sensor ends up being a small yet extremely integral component to its overall design.
Solutions from SMD Fluid Controls
If you’re a designer, repairer, or manufacturer or outdoor wood boilers and furnaces, SMD Fluid Controls offers a number of temperature sensor and liquid level sensor solutions for your specific application.
- FT20 temperature sensors
- FM22 combination temperature and level sensors
- FL-LL ultrasonic liquid level and temperature sensor
- Custom float switch and sensor design services

