The Caleffi Z55S is a Z-one motorized zone valve, 2-way with 3/4" Sweat connections, 24V.
Best for zones larger than a thermo-electric head can drive.
Specifications sourced from Caleffi North America technical literature. Last reviewed July 2026.
Key Features
Motorized Zone Control
A motor-driven actuator positions the valve on a thermostat call, suited to larger zones than a thermo-electric head can drive.
Auxiliary End Switch
An auxiliary microswitch rated 0.4 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 Zone Valve |
| Connection Size | 3/4" |
| Connection Type | Sweat |
| Configuration | 2-Way |
| Fail Position | Normally Closed |
| Flow Coefficient (Cv) | 7.5 |
| Maximum operating pressure | 300 psi |
| Medium temperature range | 32-240 °F |
| Electric supply | 24 V AC |
| Power consumption at full capacity | 7 VA |
| Auxiliary microswitch contact rating (24 V) | 0.4 A |
| Maximum glycol % | 50 % |
| Medium | water, glycol solutions, vapor (max. 15 psi) |
| Series | Z-one |
| Shipping Weight | 3.6 lb (approx.) |
Documentation
Frequently Asked Questions
What connection does Caleffi Z55S use?
It is supplied with 3/4" Sweat connections. Other sizes and connection styles in the range are listed under Related Products.
What supply voltage does Caleffi Z55S require?
Electric supply is 24 V AC, drawing 7 VA at full capacity.
What is the warranty on Caleffi Z55S?
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 Zone Valve
- Product Family:
- Motorized Zone Valves
- Series:
- Z-one
- Connection Type:
- Sweat
- Connection Size:
- 3/4 inch
- Configuration:
- 2-Way
- Fail Position:
- Normally Closed
- Flow Coefficient:
- 7.5 Cv
- Electric Supply:
- 24 V AC
- Max Operating Pressure:
- 300 psi
- Medium Temperature Range:
- 32-240 deg F