Rinnai 37AHB, 37AHB04508KA5, 37AHB06012KA5, 37AHB07514KA5, 37AHB09016KA5 Specifications

37AHB Series Hydronic Furnace

The optimum in hydronic technology, the newly
designed Rinnai® multi-position hydronic furnaces
offer a unique solution for a wide variety of small- and
medium-sized residential and light commercial
applications. They are compact and ready to fit in tight
spaces which may include, but not limited to, attics,
basements, closets, crawlspaces, and utility rooms.

Intelligent Microprocessor Controller

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.

Fine Tuned to Work with Rinnai Tankless
Water Heaters

These unique hydronic furnaces 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. When combined, the units form the Rinnai
Tankless Heating System, the first matched, tankless
hydronic heating solution in the industry!

PATENT PENDING

FEATURES

● Four models covering a range of heating capacities

○ 27,100 to 96,300 BTU/hour

● Multi-position (upflow, downflow, horizontal left,

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 motors (ECM)

● Strong 20-gauge steel cabinet

○ Galvanized, painted

○ Fully insulated cabinet

○ Low 34 inch profile

● Multi-position control box

● Designed for serviceability

● Schrader valves to purge air from the system

● Integral filter rack with filter

Part of the Rinnai Tankless Heating System

AHB90

AHB75

AHB60

AHB45

This product is manufactured in a

Equipment

CABINET

20 gauge
prepainted
galvanized steel
fully insulated

HEAT
EXCHANGER

copper tube
aluminum fin

PUMP

high-head
low-flow
integrated check valve

BLOWER
ASSEMBLY

multi-speed motor (ECM)

37AHB Series Hydronic Furnace

Accessories

THERMOSTATS

Programmable, 5-2 days;
both A/C and heat pump
versions

FLOW SENSOR *

For domestic hot water priority
* Supplied with the unit

ANTI-SCALD MIXING
VALVE

To maintain safe domestic
hot water temperature

FILTER RACK
and BOTTOM FILL PLATES

For modification to allow side-entry
return airflow

CONTROL
BOARD

integrated
microprocessor based

FILTER

Voltage Code (V- Ph-HZ)

K = 115 - 1 - 60
L = 240 - 1 - 50 (export models)

Coo ling / H e a ting
Air Flow Range ( CFM)

08 = 800 (650-800)
12 = 1200 (650-1200)
14 = 1400 (1000-1600)
16 = 1600 (1200-1750)

AHB45 (BTU) AHB60 (BTU) AHB75 (BTU) AHB90 (BTU)

120º F

27,700 36,400 43,700 54,900

130º F

33,300 45,100 52,900 63,900

in. mm in. mm in. mm in. mm in. mm

37AHB04508KA5 (AHB45) 14 355.6 18 457.2 12 304.8 10 - 1/2 266.7 19 482.6

37AHB06012KA5 (AHB60) 17 -1/2 444.5 18 457.2 16 406.4 16 - 11/16 423.9 19 - 1/ 4 489

37AHB07514KA5 (AHB75) 21 533.4 18 457.2 20 508 18 - 11/16 474.7 19 - 1/ 2 495. 3

37AHB09016KA5 (AHB90) 24 - 1/2 622.3 18 457.2 24 609.6 21 - 1/8 536.6 19 482.6

UNIT SIZE

ABCDE

37AHB spec sheet inside (7-2010).ai 7/23/2010 11:58:33 AM37AHB spec sheet inside (7-2010).ai 7/23/2010 11:58:33 AM

Optional Equipment

Nomenclature

Humidifier (HUM)

Electronic Air Cleaner (EAC)

UV Lamp

Cooling Coil

Connect an auxiliary 2.5 FLA, 2.5 LRA @ 115 VAC max Humidifier.
Connections are made via the “HUM” quick connects. The humidifier
output is on whenever a heating demand is being satisfied. The
contacts of this output are isolated to allow application of 24 VAC or
115 VAC to one terminal and the humidifier load to the other.

Connect an auxiliary Electronic Air Cleaner; rating shall be max 1.0
Amp @ 115 VAC. This output is energized whenever any of the four
blower speeds are energized. Connections are made via 0.250 x

0.032” male quick connect terminals labeled "EAC" and "N3".
Connect an auxiliary UV lamp (if required); rating shall be max 1.0

Amp @ 115 VAC. This output is energized whenever any of the four
blower speeds are energized. Connections are made via 0.250 x

0.032” male quick connect terminals labeled "UV" and "N2".
Can accomodate most brands of evaporator A-coil for cooling

applications.

FIELD-SUPPLIED ACCESSORIES capable of interfacing with the Rinnai Hydronic Furnace:

37AHB Series Hydronic Furnace

Heating Capacities

37AH B 045 08 K A 5

Multi-position

5 = Yes
2 = No

Engineering Digit

Denotes minor change

Voltage Code (V- Ph-HZ)

K = 115 - 1 - 60
L = 240 - 1 - 50 (export models)

Model

37AH - Multi - speed Hydronic Furnace

Series

A - Unit with PSC Motor
B - Unit with ECM Technology

Nominal Heating Capacit y ( BTU/h)

045 = 45, 000
060 = 60, 000
075 = 75, 000
090 = 90, 000

Coo ling / H e a ting
Air Flow Range ( CFM)

08 = 800 (650-800)
12 = 1200 (650-1200)
14 = 1400 (1000-1600)
16 = 1600 (1200-1750)

Nominal heating capacities as tested with Rinnai tankless water heaters.
For final rated capacities refer to the Air Delivery and Performance
Tables in the Operation and Installation Manual.

AHB45 (BTU) AHB60 (BTU) AHB75 (BTU) AHB90 (BTU)

120º F

27,700 36,400 43,700 54,900

130º F

33,300 45,100 52,900 63,900

in. mm in. mm in. mm in. mm in. mm

37AHB04508KA5 (AHB45) 14 355.6 18 457.2 12 304.8 10 - 1/2 266.7 19 482.6

37AHB06012KA5 (AHB60) 17 -1/2 444.5 18 457.2 16 406.4 16 - 11/16 423.9 19 - 1/ 4 489

37AHB07514KA5 (AHB75) 21 533.4 18 457.2 20 508 18 - 11/16 474.7 19 - 1/ 2 495. 3

37AHB09016KA5 (AHB90) 24 - 1/2 622.3 18 457.2 24 609.6 21 - 1/8 536.6 19 482.6

UNIT SIZE

ABCDE

Dimensions

Minimum Clearance to

Combustible Construction

Warranty

* In order to receive full warranty coverage on the Hyrdronic Furnace when connected to any other type or
brand of product other than a Rinnai tankless water heater, the flow rate through the Hydronic Furnace
must not exceed a maximum of 5 GPM.

Rinnai will repair or replace the covered product or any part or component that is defective in materials or
workmanship as set forth.

Rinnai will pay reasonable labor charges associated with the repair or replacement of any such part or
component.

Parts: 5 years * / Labor: 1 year *

37AHB Series Hydronic Furnace

6"

17 13/ 16"

1"

18 5/16"

1"

C

B

34"

A

22"

E

13/8"

D

17 13/16"

21/8"

TOP/PLENUM

zero

SIDE

zero

BACK

zero

SIDE

zero

FRONT

zero

BOTTOM

zero

SERVICING

24” (610 mm)

in. mm in. mm in. mm in. mm in. mm

37AHB04508KA5 (AHB45) 14 355.6 18 457.2 12 304.8 10 - 1/2 266.7 19 482.6

37AHB06012KA5 (AHB60) 17 -1/ 2 444.5 18 457.2 16 406.4 16 - 11/ 16 423.9 19 - 1/4 489

37AHB07514KA5 (AHB75) 21 533.4 18 457.2 20 508 18 - 11/16 474.7 19 - 1/2 495.3

37AHB09016KA5 (AHB90) 24 - 1/2 622.3 18 457.2 24 609.6 21 - 1/8 536.6 19 482.6

UNIT SIZE

ABCDE

Air Delivery

37AHB Series Hydronic Furnace

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

TAP 3 (H) 2.0 948 921 891 868 841 819 795 772 701 596 567

TAP 4 (M) 2.0 921 891 864 836 812 788 768 742 699 594 559

TAP 5 (L) 1.5 803 768 740 712 682 652 628 596 569 541 510

TAP 1 (H) 3.0 1343 1318 1296 1270 1248 1225 1197 1168 1109 1025 889

TAP 2 (MH) 2.5 1148 1128 1103 1072 1045 1012 984 955 937 908 690

TAP 4 (ML) 2.0 971 942 911 880 847 817 784 751 715 680 642

TAP 5 (L) 1.5 844 810 777 734 698 665 626 581 533 504 466

TAP 1 (H) 4.0 1700 1666 1635 1604 1576 1543 1518 1492 1465 1430 1402

TAP 2 (MH) 3.5 1561 1524 1490 1456 1428 1396 1364 1330 1230 1265 1224

TAP 3 (ML) 3.0 1391 1350 1320 1281 1245 1209 1190 1131 1090 1064 1031

TAP 4 (L) 2.5 1222 1174 1140 1100 1063 1014 979 937 887 829 777

TAP 1 (H) 5.0

1934 1889 1857 1818 1784 1750 1715 1680 1568 1491 1377

TAP 2 (MH) 4.0

1777 1732 1694 1650 1630 1592 1553 1517 1464 1441 1361

TAP 3 (ML) 3.5

1573 1530 1490 1448 1417 1372 1327 1293 1253 1221 1175

TAP 4 (L) 3.0

1400 1351 1317 1275 1225 1183 1134 1095 1053 1011 951

AIRFLOW (CFM)

NOM INA L AIR DELIVERY CHART ( B OTTO M O R S IDE RETURN w/ FILTE R)

External Static Pressure (ESP)

ECM SPEED

TAP

SUPPORTS

COOLING

CAP. RANGE

(TONS)

Specifications

† Tested in accordance with ANSI/ASHRAE Standard 37-Latest edition.

‡ Airflows shown are nominal (blower speeds are factory set). For air
delivery other than stated, refer to the Air Delivery & Performance table.

Side intake filter to be (1) 20”x20”x1” typical for all models.

Air filter pressure drop for non-standard filters must not exceed 0.08 in. wg.

This product is manufactured in a facility registered by UL to ISO 9001.

37AHB Series Hydronic Furnace

37AHB spec sheet cover (7-2010).ai 7/23/2010 10:16:37 AM37AHB spec sheet cover (7-2010).ai 7/23/2010 10:16:37 AM