The Caleffi 638074A 103 is a 2-Way High-Flow motorized ball zone valve with 1-1/4" NPT connections, 24V.
Best for zones needing low pressure drop and positive shutoff, including larger branches and snowmelt loops.
Specifications sourced from Caleffi North America technical literature. Last reviewed July 2026.
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 6 A at 24 V confirms valve position for pump or boiler interlock.
Glycol Compatible
Rated for glycol solutions to 50 %, covering freeze-protected circuits.
Technical Specifications
| Product Type | Motorized Ball Zone Valve |
| Connection Size | 1-1/4" |
| Connection Type | NPT |
| Configuration | 2-Way |
| Flow Coefficient (Cv) | 56 |
| Maximum operating pressure | 230 psi |
| Medium temperature range | 14 - 230 °F |
| Ambient temperature range | 14 - 230 °F |
| Protection class | IP 65 |
| Auxiliary microswitch contact rating (24 V) | 6 A |
| Maximum glycol % | 50 % |
| Medium | water, glycol solutions |
| Series | 2-Way High-Flow |
| Shipping Weight | 5.6 lb |
Documentation
Related Products
- Caleffi 638074A 106 : Motorized Ball Valve 2-Way 1-1/4" Press 24V
- Caleffi 638074A 109 : Motorized Ball Valve 2-Way 1-1/4" Sweat 24V
- Caleffi 638054A 103 : Motorized Ball Valve 2-Way 3/4" NPT 24V
- Caleffi 638054A 106 : Motorized Ball Valve 2-Way 3/4" Press 24V
Frequently Asked Questions
What does Caleffi 638074A 103 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 638074A 103 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 638074A 103 use?
It is supplied with 1-1/4" NPT connections. Other sizes and connection styles in the range are listed under Related Products.
What is the warranty on Caleffi 638074A 103?
Caleffi covers this product under its standard two-year limited warranty against defects in material and workmanship from the date of shipment. ZOT Supply is an authorized Caleffi distributor.
- Product Type:
- Motorized Ball Zone Valve
- Product Family:
- Motorized Ball Zone Valves
- Series:
- 2-Way High-Flow
- Connection Type:
- NPT
- Connection Size:
- 1-1/4 inch
- Configuration:
- 2-Way
- Flow Coefficient:
- 56 Cv
- Max Operating Pressure:
- 230 psi
- Medium Temperature Range:
- 14 - 230 deg F