Viessmann Vitocrossal 300 CU3A-160 Floor-Standing Condensing Boiler, 160 MBH

The Viessmann Vitocrossal 300 CU3A-160 is a heat-only gas condensing boiler that stands on the floor, sized for replacing boilers on cast-iron radiators and for fin-tube systems with several zones. It modulates from 43 to 160 MBH at 95% AFUE and carries 18.8 gal of boiler water.

Its high-mass stainless-steel Inox-Crossal heat exchanger works with a MatriX modulating dome burner for a Net AHRI rating of 129 MBH, and efficiency climbs to 98% at low return temperatures. Sound ranges from 33 dB at minimum to 53 dB at maximum, condensate reaches about 1.6 USG/h, and operation up to 10,000 ft is possible with de-rate. A Vitotronic 200 outdoor-reset control supports multi-circuit systems.

The direct-vent design uses a 4 in. flue with 3 in. combustion air in coaxial or two-pipe layouts, with allowable vent lengths up to about 198 ft depending on layout. Connections are 1¼ in. NPTM heating supply and return, ¾ in. NPTF gas and PRV, and a 1 in. NPTM boiler drain. It is pre-wired, internally piped and factory set for natural gas, with LP conversion labels supplied.

Highlights

• 43-160 MBH input; Net AHRI 129 MBH

• 95% AFUE, up to 98% efficiency at low return temperatures

• 18.8 gal water content helps limit short cycling

• Outdoor-reset Vitotronic 200 control, outdoor sensor supplied

• Direct vent: 4 in. flue, 3 in. air, runs up to about 198 ft

• ENERGY STAR; built to ASME Section IV and CSA B51

Specifications

In the box

• Vitotronic 200 outdoor-reset control with outdoor sensor

• Installation fittings with 30 psig PRV

• Temperature and pressure gauge

• LP conversion labels

Good to know

• Gas-fired appliance: it must be installed, vented and commissioned by a qualified installer in line with local codes and the manufacturer's installation manual.