The Caleffi ROBOCAL Series 5025 Automatic Air Vent with Integral Automatic Shut-off Cock (MPN 502530) is a 3/8" BSP male-threaded float-type automatic air vent distinguished by its built-in automatic shut-off cock. When the vent body is unscrewed from its base, an EPDM O-ring-sealed piston closes automatically, isolating water flow without any manual valve operation or system drain-down. This makes the 502530 the preferred choice wherever routine vent maintenance is anticipated. The Series 5025 features a horizontal discharge orientation and is rated to 10 bar / 110°C, with a maximum discharge pressure of 4 bar.
Auto Shut-off
Integral Cock
The Key Feature: Automatic Shut-off
When the vent body is unscrewed from the base for inspection or replacement, a spring-loaded EPDM O-ring-sealed piston closes automatically — stopping water flow at that connection without any manual valve. This allows vent servicing without isolating the circuit or draining the system.
Discharge Pressure Rating
Series 5025 (502530) is rated to a max discharge pressure of 4 bar. This is lower than Series 5026 (6 bar). Verify system pressure at the installation point is within this limit before specifying.
Installation Orientation
Must be installed vertically upright. The float mechanism operates on gravity — tilted or inverted installation will prevent correct operation.
Key Features
🔒
Automatic Shut-off on Removal
The integral shut-off cock closes the moment the vent body is unscrewed — no manual valve to remember to close, and no risk of water discharge during vent removal. EPDM O-rings provide long-term seal reliability.
🫧
Float-Type Auto Venting
Air accumulates in the body → float falls → obturator opens → air vents. Water replaces air → float rises → obturator seals. The same proven Robocal float mechanism as the standard Series 5026.
🛡
Dry Obturator
The obturator seal is positioned away from direct contact with system water, preventing contamination from sludge, magnetite, and scale that would otherwise degrade the seal over time.
↔️
Horizontal Discharge
The Series 5025 vents horizontally — well-suited to locations where vertical clearance above the vent connection is restricted, or where the discharge direction must be directed away from sensitive components.
Technical Specifications
| MPN |
502530 |
| Series |
5025 — ROBOCAL with Automatic Shut-off Cock |
| Connection |
3/8" BSP Male (external thread) |
| Discharge Direction |
Horizontal |
| Body / Cover Material |
Brass EN 12165 CW617N |
| Float Material |
Polypropylene (PP) |
| Obturator Material |
Silicone rubber |
| Spring Material |
Stainless steel 1.4310 / AISI 302 |
| Seals — body |
EPDM |
| Seals — shut-off cock |
PTFE |
| Medium |
Water; glycol solutions max 30% |
| Max Working Pressure |
10 bar |
| Max Discharge Pressure |
4 bar |
| Max Working Temperature |
110°C |
| Body Dimensions (approx.) |
Height 72mm; Body diameter Ø40mm; D: 25mm; E: 57mm; F: 10mm |
| Weight |
approx. 0.167 kg |
| Manufacturer |
Caleffi S.p.A., Italy |
Frequently Asked Questions
What is the key difference between 502530 and 502630?
502530 (Series 5025): 3/8" BSP, horizontal discharge, integral automatic shut-off cock, 4 bar max discharge pressure, 110°C max. 502630 (Series 5026): 3/8" or ½" BSP, vertical discharge, no shut-off cock, 6 bar max discharge pressure, 115°C max. Choose 502530 where maintenance access and serviceability are priorities.
Can I service this vent without draining the heating system?
Yes — this is the primary advantage of the 5025 series. Unscrewing the vent body activates the automatic shut-off, stopping water at that point. You can remove, inspect, and replace the vent without draining or isolating the wider circuit.
What size fitting does the 502530 need?
3/8" BSP male (external thread). Common installation positions include buffer vessel tappings, boiler manifold connections, and proprietary system ports with 3/8" female tappings. Confirm the thread size at your installation point before ordering.
Is this vent suitable for solar thermal systems?
Provided the operating temperature and pressure remain within the rated limits (10 bar, 110°C), and glycol concentration does not exceed 30%, the 502530 is compatible with solar thermal primary circuits. However, at high solar temperatures (above 100°C), consult the system designer — some solar primary circuits operate above the 110°C rating of the 5025 series.
Does the 502530 need an additional isolation valve?
No — the integral automatic shut-off cock fulfils the isolation function during vent removal. An upstream isolation valve is not required for routine maintenance, though one may be desirable for full circuit isolation during commissioning or system drain-down.
