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The Rinnai 37AHB07514KA5 has been discontinued.
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(800) 865-5931

Mon-Fri 8am-7pm, Sat 9am-2pm CT

The newly designed Rinnai® multi-position hydronic air handlers offer a unique solution for a wide variety of small and medium sized residential and light commercial applications.  They are compact and able to fit in tight spaces which may include attics, basements, closets, crawlspaces and utility rooms.

The 37AHB units are equipped with an intelligent microprocessor control that allows for domestic hot water priority and adapts to available hot water flow for space heating by automatically regulating the pump and fan sequence to maximize comfort.

These unique hydronic air handlers are designed to work in combination with our line of Rinnai tankless water heaters to deliver heating capacities that cover a wide spectrum of residential and light commercial heating applications.  For these air handlers to provide cooling, a seperate outdoor condenser and evaporator coil must be installed.

Standard Features

  • Multi-position: Upflow, downflow, horizontal left or horizontal right without modifications
  • Modifiable for side-entry return air
  • Low-flow, high-head pump custom designed to work with Rinnai's tankless water heaters
  • Integrated control board with learning algorithm
  • No combustion air infiltration losses when used with a Rinnai tankless water heater
  • Four selectable heat blower off delay times
  • Multi-speed ECM motor
  • 20 gauge, prepainted, fully insulated, galvanized steel 
  • Multi-position control box
  • Designed for serviceability
  • Schrader valves to purge air from the system
  • Integral filter rack with filter
  • Five year parts, 1 year labor warranty


Configuration is the direction the conditioned air will pass through the unit.

Upflow units will have the air come in from the bottom and blow out the top.

Horizontal units will have the air go through the unit left to right, or right to left.

Downflow units will have the air come in from the top of the unit, and blow out the bottom.

Unsure of what configuration your home needs? Call us at 800-865-5931. Monday through Friday, 8:30am to 5:00pm CST

Downflow / Horizontal / Upflow
Blower Cooling Capacity

The tonnage of air conditioning that can be moved effectively by the blower. You want to make sure that the blower is appropriately sized for the air conditioner. If it is too small the coil could ice up. If it is too large than the air coming out of the ducts won't be cold enough.

Blower Cooling Capacity
2.5 / 3 / 3.5 / 4 Tons
Maximum Heating Output BTU

The amount of heat, rated in British Thermal Units (BTUs), that the unit can deliver into the space. Not sure how many BTUs you need? Try our easy Equipment Sizing Estimator.

Maximum Heating Output BTU
75000 BTU
Nominal CFM

The amount of air that can be moved by the fan, measured in cubic feet per minute (cfm).

Nominal CFM
Blower Type

There are three main type of blowers: Multi-Speed, High-Efficiency Multi-Speed, and Variable Speed.

Standard Multi-Speed blowers have different speed options and you select the speed that the blower will operate at depending on the function it is performing (ex. different speeds for fan, AC, and heating functions).

High-Efficiency Multi-Speed blowers are designed to maintain a constant torque and in doing so will maintain air-flow and use less electricity.

Variable Speed blowers will adjust their speed during operation. The result is a blower that will run at lower speeds for longer periods of time (this improves the air flow and increases electrical efficiency).

Blower Type
Maximum Fuse/Breaker

The maximum capacity breaker that the unit can be connected to (This is the best option for consistent performance)

Maximum Fuse/Breaker
20 Amps
Fuel Type
Water Connection- Inlet
3/4 inches
Water Connection- Outlet
3/4 inches
Product Weight
138 lbs
21 Inches
22 Inches
34 Inches
115 Volts
Limited Warranty
5 Years