null Skip to main content
Caleffi 644356A 3BY : Motorized Ball Valve 3-Way Bypass 3/4" Press

Caleffi 644356A 3BY : Motorized Ball Valve 3-Way Bypass 3/4" Press

Caleffi

MSRP: $453.00
Your Price:  $303.28
(You save $149.72 )
(No reviews yet) Write a Review
SKU:
644356A 3BY
UPC:
8016615471243
Condition:
New
Availability:
Ships in 1 Week
Adding to cart… The item has been added
Flow Coefficient12 Cv open / 2.1 Cv by-pass
Connection3/4" Press
Configuration3-Way Bypass
Electric Supply24 V AC
Warranty2-Year Limited

The Caleffi 644356A 3BY is a 3-Way Bypass motorized ball zone valve with 3/4" Press connections.

Best for zones needing low pressure drop and positive shutoff, including larger branches and snowmelt loops.

Specifications transcribed from Caleffi technical brochure 01131/23 NA. Last verified August 2026.

Warranty

Caleffi 2-Year Limited Warranty. Caleffi North America warrants this product free from defects in material and workmanship for two years from the date of transfer of ownership - the point Caleffi hands the goods to the first carrier - subject to correct installation and use. Coverage runs to the purchaser identified as "Ship To" on Caleffi's order confirmation and is subject to the eligibility conditions, exclusions and remedies set out in Caleffi North America's published Limited Warranty and Terms and Conditions of Sale. This summary is provided for convenience and does not replace those documents.

Key Features

Full-Port Ball Design

A ball closure gives a full-port, low-pressure-drop design when open and tight shutoff when closed, unlike a characterized globe seat.

Motorized Actuation

A synchronous motor drives the ball open and closed on a thermostat signal, with an auxiliary end switch available for pump or boiler interlock.

Auxiliary End Switch

An auxiliary microswitch rated 5 A at 24 V confirms valve position for pump or boiler interlock.

Technical Specifications

Product TypeMotorized Ball Zone Valve
Connection Size3/4"
Connection TypePress
Configuration3-Way Bypass
Flow coefficient (Cv)12 Cv open / 2.1 Cv by-pass
Medium temperature range20-230 °F
Electric supply24 V AC
Power consumption at full capacity4 VA
Auxiliary microswitch contact rating (24 V)5 A
closing delta p max.150 psi
Series3-Way Bypass
Published weight (Caleffi "Wt.")2.6 lb

Documentation

PDF
PDF

Related Products

Frequently Asked Questions

What does Caleffi 644356A 3BY do?

It is a motorized ball zone valve. A motor drives a full-port ball open and closed on a thermostat call, giving very low pressure drop when open and tight shutoff when closed.

How is Caleffi 644356A 3BY different from a thermo-electric zone valve?

A ball valve gives a full-port, low-pressure-drop path and positive shutoff, and suits larger zones. A thermo-electric valve is smaller and silent but has a characterized seat with higher pressure drop.

What connection does Caleffi 644356A 3BY use?

It is supplied with 3/4" Press connections. Other sizes and connection styles in the range are listed under Related Products.

What supply voltage does Caleffi 644356A 3BY require?

Electric supply is 24 V AC, drawing 4 VA at full capacity.

Caleffi 2-Year Limited Warranty. Caleffi North America warrants this product to be free from defects in material and workmanship for two years from the date of transfer of ownership (when the goods are handed to the first carrier), when installed and operated in accordance with published instructions. Coverage runs to the purchaser identified as "Ship To" on Caleffi's order confirmation and is subject to the eligibility conditions, exclusions and remedies set out in Caleffi North America's published Limited Warranty and Terms and Conditions of Sale. This summary is provided for convenience and does not replace those documents. ZOT Supply is an authorized Caleffi distributor.
Product Type:
Motorized Ball Zone Valve
Product Family:
Motorized Ball Zone Valves
Series:
3-Way Bypass
Connection Type:
Press
Connection Size:
3/4 inch
Configuration:
3-Way Bypass
Electric Supply:
24 V AC
Medium Temperature Range:
20-230 deg F
Flow Coefficient:
12 Cv open / 2.1 Cv by-pass
!