AirFoX (AFX) Heat Recovery Unit

Heat water for free with an AirFoX Desuperheater!

•    Reduce Energy Consumption 

•    Increase SEER rating

•    Lower Greenhouse Gas Emissions

The AirFoX desuperheater redirects 100% of the superheat that is customarily blown out into the atmosphere from air conditioners, heat pumps, and refrigeration systems, into the water heater tank - creating hot water – for FREE!

Desuperheating lowers the refrigerant temperature and pressure, which reduces the energy input to the compressor and increases the cooling efficiency of the system.  It can also increase the SEER rating to 1.4.

Desuperheaters are ideal in places that use cooling units year-round.  For instance, a single-family home can often turn off the water heater because of the high temperatures transferred to the cold water supply.  For businesses across the region, desuperheaters can reduce the number of boilers needed for overall water heating of the facilities.

The refrigerant side of the AirFoX installs refrigerant hot gas line between the compressor and condenser.  If installed with a Heat Pump System, then go between the compressor and reversing valve. The waterside is connected to the water heater tank to form a circulation loop. The power is drawn from the compressor contactor.

Waste heat may be collected when the compressor operates, and the water circulating from the water heater tank is less than 140ºF. A minimum refrigerant temperature of 125ºF is also required to allow Heat Recovery Operation

desuperheater heat recovery unit
desuperheater heat recovery unit

Heat Recovery Unit Installation Diagram

Installation Specifications


Refrigerant: Run the copper hot gas line from the A/C compressor to the AirFoX and back to the condenser coil. See installation instruction for line sizing - never reduce hot gas line size below that in the A/C. On Heat Pumps: run the line from the compressor to the AirFoX and back to the heat pump ahead of the four-way reversing valve.  When possible install above the compressor. Insulate all lines.

Water: Run lines above ground or roof on 4×4″ blocks.  Place check valve in water line (out) on multi-unit applications to prevent re-circulation.
Use copper pipe for long life.

Cabinet: May be installed horizontally or vertically. Never install with pump or access door facing down.

HRU Mounting Location & Controls

Heat Recovery Units may be mounted indoors or outdoors. They must be mounted vertically, at a height above the top of the condenser. While normally located outdoors near the air conditioning equipment, they can be placed in any convenient place, such as the garage or laundry room; but the refrigerant run should be kept to a minimum.

All models contain a water high limit control; factory set to 140ºF. Models also include a refrigerant gas low limit; factory set to 125ºF. Models with optional freeze-protection are equipped with a water low limit; factory set to 50ºF and is designed to operate when water temperatures of 40ºF or less are detected. Providing water circulation independent of compressor operation in the event of freezing ambients.

Heat Recovery Units contain a corrosion resistant all-copper double wall heat exchanger of counterflow twin tube design. Continuously vented along its entire length, the Heat Exchanger meets strict IAPMO safety criteria and exceeds UL requirements. Operating pressure, 650 psig, refrigerant, 150 psig water side (for use with R-12, 22, 410, 500 & 502)

Circulator Pump

Heat Recovery Units contain a low wattage wet rotor in-line single stage circulator. Standard Models use a Taco 006 series circulator. This water-cooled pump is rated at 90 watts, 230 volts, and 0.40 amps. It is designed for 125 psi working pressure and up to 220ºF fluid temperature. The pump housing is bronze with ceramic bearings.

Limited Warranty

Heat Exchanger - 5 Years

Pump - 3 Years; All other components - 1 Year

CAUTION: Installations subject to freezing ambient must make provision for freeze protection. Heat Recovery Units containing freezestats must draw power from the line side of the compressor contactor. Drainable hand valves offer positive freeze protection.