Collection: Hydronics Accessories and Parts

Most systems just need a thermostat and basic fittings out of the box. Beyond that, what you need depends on your setup — pressure testing kits and tools for install, antifreeze if there's freeze risk, and pump or heat exchanger upgrades only if you're adding zones or heat sources.

These are built and tested specifically for HUG Hydronics systems. Some components, like standard thermostats and PEX fittings, are compatible with other hydronic setups too — check the individual product page for compatibility notes.

The thermostat sets the temperature you want. The RIB (relay) lets the system trigger outside devices, like a boiler or pump. The zone expander adds capacity for more heating zones — you only need it if you're running more zones than the 4 the control board supports out of the box.

The pump upgrades are only available for heater pumps, and are only needed if the boiler requires that level of flow. All the boilers we sell should have a notice which heat pump belongs with it.

For custom flow setups or unique applications, connect with our engineering team — ask for Ryan.

Use propylene glycol antifreeze — it's non-toxic and safe for closed hydronic loops. We suggest about 33% (one part antifreeze to two parts water); up to 50% works if you need more freeze protection. We carry it in 5-gallon quantities, sized for a typical single-zone system.

Yes — everything on this page is sold individually. If you're not sure which specific part failed, our support team can help you identify it before you order.