What's an Aquastat?

An aquastat is a water-temperature control that functions much like a thermostat for your outdoor wood boiler. Depending on the system’s configuration, it may control the combustion fan, circulator pump and backup heating system to maintain safe water temperatures and help keep your home adequately heated. Read on to learn about the different types of aquastats and what to consider when choosing one, or contact Alternative Heating & Supplies for assistance.

Types of Aquastats

There are two main types of aquastats for boilers: strap-on and digital.

• Strap-on aquastats are placed on the outside of the water pipe and read temperature through the metal using a heat-sensitive element.
• Digital aquastats measure the water temperature using a digital temperature sensor, which may be immersed in the water with an immersion well or strapped onto the pipe. They feature display screens that allow for precise temperature identification and differentials.

How to Select the Right Aquastat for Your Outdoor Wood Boiler

So, what type of aquastat is best for your outdoor wood boiler? A digital or strap-on? Both types have their share of pros and cons — here's a closer look at the various factors to weigh to help you make the right choice.

• Temperature range and accuracy: If you're looking for a precise aquastat, digital models are your best bet, as they are placed right in the boiler water and can quickly and accurately read temperature. Strap-ons are also accurate, but take longer to respond because the heat has to first pass through the pipe wall. In terms of temperature range, digital thermostats have wider operational ranges to further fine-tune shut-offs and differentials.
• Compatibility: Strap-on aquastats are non-invasive and very easy to install, simply clamping against the existing pipe. Digital thermostats often have to be placed physically into the boiler water.
• Control type: Strap-ons have a switch that breaks contact on temperature rise and makes contact, relying on a mechanical wheel to adjust the differential. Digital thermostats offer more advanced customization, allowing for the programming of on/off trigger points and differentials down to the degree. Many digital aquastats also offer Wi-Fi monitoring and other advanced features.
• Voltage: Your aquastat's voltage should be adjusted based on the equipment it controls. If it's just tying into your indoor thermostat system, low-voltage is suitable. If it's powering the blower fan or circulator pump, line-voltage should be considered.

Contact Alternative Heating & Supplies

For more information on aquastats and finding the right digital and strap-on models for your outdoor wood boiler, contact us today. Alternative Heating & Supplies is also a leading supplier of outdoor wood boiler parts, and maintenance kits.