Armstrong ABH gas-fired water heater assemblies are engineered for reliable, high-efficiency hot water generation. They include The Brain® Digital Recirculation Valve (DRV) for precision digital water temperature control and SAGE® Smart Hot Water System Monitoring and Documentation software for a comprehensive pre-piped packaged solution. The ABH components are designed and manufactured to match the exact requirements of the installation site, shipping fully assembled to minimize on-site work.

Generation and Condensing Technology

ABH Gas Fired Water Heaters deploy an innovative, multiple pass condensing technology to deliver operating efficiencies as high as 99.8%. During operation, the energy from the latent and sensible heat from the combustion process is fully optimized by the heat exchanger.

A unique, patented Cold Water Injection System (CWIS) within the storage tank ensures that the lowest achievable temperature cold and/or system return water enters the heat exchanger of the ABH. This design maximizes the condensing condition across a broader operational range than competitive, high-efficiency technologies.

Control and Connectivity

ABH Water Heating Systems are designed to efficiently heat and circulate the water between the heat exchanger and tank at 140ºF or higher to mitigate the incubation of waterborne pathogens, while still optimizing the ABH condensing combustion process.

Integral and site-programmable, The Brain® Digital Recirculating Valve is provided pre-piped and factory set to deliver safe, reliable hot water to the building plumbing system. Each assembly is also provided with the SAGE® Smart Hot Water System Monitoring and Documentation platform, featuring an integral MODBUS RTU for direct connectivity to BAS. SAGE® modules are available with specific ProtoCessor cards for BAS connectivity to systems operating on MODBUS TCP, BACnet™, or LonWorks™ protocols.

Operational Specifications

• +/-2°F (1°C) DRV water temperature control at peak, moderate or zero fixture demand on hot water system designed for continuous recirculation
• 1°F (1°C) minimum recirculating water temperature differential
• LCD display which indicates: set point, delivered temperature, error codes and alarm conditions capable of BAS and mobile connectivity
• Programmable set point range of 81-158°F (27-70°C)
• Programmable thermal disinfection range of 158-185°F (70-85°C)
• Automatic safe closure of hot water inlet in response to: inlet supply failure, 120V power failure, or programmable high temperature error
• Patented Cold Water Injection System (CWIS)

Technical Specifications

• Gas Pressure: Maximum 14” (356mm); Minimum 4” (102mm)
• Minimum recirculation flow: 2 GPM (7 LPM) per DRV25, 5 GPM (19 LPM) per DRV40, 10 GPM (37.9LPM) per DRV80
• Power Supply: 120 volt power supply required for DRV; 208-240V, Single Phase for ABH
• Compliance: Complete assembly lead-free compliant; DRV conforms to ASSE 1017, CSA B125.3-11, UL E357437, and CE; ABH conforms to ANSI Z21.13-2014/CSA 4.9-2014, UL795/CSA3.4, AHRI, ASME H Stamped

Standard Materials of Construction

• Heat Exchanger: 316L Stainless Steel
• Water Pipe: Type L Copper
• Fittings: Lead-Free Brass/Bronze
• Digital Mixing Valve: 316L Stainless Steel
• Frame: Fabricated Carbon Steel Frame With Machine Grade Enamel Paint
• Venting: Stainless Steel
• Storage Tank: Glass Lined ASME Rated

Heat Exchanger Capacities

Model	Input (BTU/hr)	Input (kW)	Output (BTU/hr)	Output (kW)	Recovery @ 100°F ΔT (GPH)	Recovery @ 100°F ΔT (LPH)	Water Flow Rate & Pressure Drop
ABH 299	300,000	88	up to 291,000	up to 85	360	1363	16.5 GPM @ 22.9' (62 LPM @ 7M)
ABH 399	399,999	117	up to 387,999	up to 114	466	1764	26.4 GPM @ 20.3' (100 LPM @ 6M)
ABH 599	630,000	185	up to 611,100	up to 179	734	2778	39.6 GPM @ 23.6' (150 LPM @ 7M)

(Rates shown are for natural or propane gas, and elevations up to 9000 feet. BTU/kW input indicated at 97% thermal efficiency with 86°F incoming supply.)

Maintenance and Cleaning

WARNING

These appliances MUST be installed by a properly licensed individual in the City and State in which the unit is being installed. All start up adjustments and subsequent service work must be done by a similarly licensed contractor or a factory trained service individual. Failure to comply could result in loss of warranty and or severe personal injury, death and or substantial property damage.

All high-efficiency condensing appliances will require more maintenance (cleaning) than their non-condensing counterparts. In some extreme applications (hard water and/or higher than normal operating temperatures), the heat exchanger may require chemical cleaning. DS40 FERNOX is the descaling solution recommended for the stainless steel heat exchanger. Chemical cleaning of the heat exchanger should only be done at the direction of Armstrong Hot Water, Inc.