Vibiemme Domobar & Lollo Boiler Pressure Switch Regulator – Replacement Part

Vibiemme Domobar & Lollo Boiler Pressure Switch Regulator

OEM-specification replacement boiler pressure switch regulator for Vibiemme (VBM) Domobar and Lollo espresso machines. The pressure switch controls boiler temperature by switching the heating element on and off at the set pressure point. When it fails, the boiler can overheat, causing steam pressure to exceed safe operating limits and triggering the safety valve.

Compatible Models

Part Details

• Brand: Vibiemme (VBM)
• Compatible Models: Domobar, Lollo
• Type: Boiler pressure switch regulator
• Tools required: 17mm or 19mm spanner, flat-head screwdriver

VBM Domobar Overheating or Safety Valve Blowing? A Short Maintenance Guide

If your Vibiemme Domobar or Lollo is building excessive steam pressure — especially if steam is escaping from the safety valve — the boiler pressure switch is almost certainly the cause. Here’s how to understand the fault and replace the switch safely.

How the Pressure Switch Works

The boiler pressure switch monitors steam pressure inside the boiler. When pressure reaches the upper set point (typically around 1.2–1.3 bar on the Domobar), the switch opens and cuts power to the heating element. As the boiler cools and pressure drops to the lower set point, the switch closes and the element heats again. This cycle maintains a stable boiler temperature. When the switch fails — usually sticking in the closed position — the element runs continuously, boiler pressure climbs above 1.5 bar, and the safety valve lifts to prevent damage.

Signs the Pressure Switch Has Failed

• Steam pressure exceeding 1.5 bar — the boiler pressure gauge climbs higher than normal operating range and does not stabilise.
• Safety valve discharging steam — steam or water venting from the safety valve on the boiler is a clear sign pressure is beyond the safe limit.
• Machine constantly overheating — the machine feels excessively hot, steam wand pressure is unusually strong, or the machine takes much longer than normal to cool down between uses.
• No steam pressure building — a pressure switch stuck in the open position will prevent the element from heating at all, resulting in no steam.

How to Replace the Pressure Switch

1. Switch off the machine and isolate from mains power. Allow it to cool completely and depressurise fully before opening.
2. Photograph the existing wiring before disconnecting anything — this ensures correct reconnection of the switch terminals.
3. Use a 17mm or 19mm spanner to unscrew the old pressure switch from the boiler fitting. Support the boiler fitting with a second spanner if needed to avoid stressing the boiler.
4. Apply PTFE tape to the thread of the new switch if required and screw it into the boiler fitting.
5. Reconnect the wiring terminals using your photograph as a reference.
6. Restore power, heat the machine, and verify that boiler pressure stabilises within the normal operating range before returning to service.

Frequently Asked Questions

Can I adjust the pressure switch instead of replacing it?

Some pressure switches have an adjustment screw that allows the set point to be raised or lowered. However, if the switch has failed internally and is no longer cycling correctly, adjustment will not restore reliable function. Replacement is the only permanent fix for a failed switch.

Will this pressure switch fit other VBM models?

This switch is confirmed for the Vibiemme Domobar and Lollo. Other VBM models may use different pressure switches. Contact Bear Coffee Machine to confirm compatibility before ordering.

Do you ship Australia-wide?

Yes. Bear Coffee Machine ships to all Australian states and territories with fast dispatch.