MVVS2.5 | Vacuum Switch 2.5, 580 PSI, 220V 16A

MVVS2.5 | Vacuum Switch 2.5, 580 PSI, 220V 16A

The MVVS2.5 Vacuum Switch is a safety-critical accessory designed
for tank-fed pressure washer systems that need reliable low-water protection.
Set to close at approximately 2.5″ Hg of vacuum, this
normally-open switch monitors suction at the pump inlet and only allows the
burner or control circuit to energize when adequate water supply is present.
When vacuum is lost—such as when the pump stops or the bulk tank runs dry—
the switch opens, interrupting power and helping to prevent catastrophic
dry-running, overheating, and component damage.

• Normally-open vacuum switch that closes when pump vacuum is detected.
• Setpoint at 2.5″ Hg for reliable sensing on tank-fed systems.
• Recommended for pressure washers in the 3.0–4.5 GPM range.
• Rated up to 16 A contact load for burner and control circuits.
• 1/4″ FPT connection for simple plumbing into the suction line.

How the MVVS2.5 Works

Installed in the inlet plumbing between the tank and pump, the MVVS2.5
senses the vacuum generated as the pump draws water. During normal operation,
inlet suction deflects the internal diaphragm and closes the
electrical contacts, allowing power to flow to the burner, solenoid, or
control relay. If flow stops or the tank runs dry, vacuum collapses, the
diaphragm returns to its rest position, and the contacts open,
immediately removing power from the heating or process circuit.

Operating sequence

• Pump running, water available: inlet vacuum reaches 2.5″ Hg or higher; switch closes and enables the burner/control circuit.
• Pump stopped or tank empty: vacuum drops; spring returns diaphragm; switch opens and shuts the circuit down.
• Automatic reset: when water supply is restored and vacuum is present again, the switch recloses without manual intervention.

Construction and Ratings

The MVVS2.5 is built as a compact, rugged assembly suitable for cabinet-style
units, hot-water skids, and trailer rigs. A vacuum-sensing diaphragm,
mechanical return spring, and robust contact set are housed in a durable
body designed for the vibration and moisture typical of professional pressure
washing environments. Electrical ratings and fluid limits are sized for
common burner controls and safety circuits used in commercial machines.

• Vacuum setpoint: 2.5″ Hg (closes on vacuum, opens on loss of vacuum).
• Contacts: rated up to 16 A at typical line voltage.
• Fluid connection: 1/4″ FPT port for easy installation.
• Max water temperature: approximately 131°F (55°C) in standard configurations.
• Approximate weight: about 1.25 lb, compact for skid and cabinet layouts.

Design advantages

• Simple mechanical design—no electronics or programming required.
• Field-proven Mecline / AR pattern widely used in professional equipment.
• Compact footprint for tight engine decks, enclosures, and control panels.
• Two-wire switch configuration for straightforward series wiring with other safeties.

System Integration

The MVVS2.5 is typically installed on tank-fed pressure washers
operating between 3.0 and 4.5 GPM, where verifying water supply
before heat is essential. It is usually wired in series with flow switches,
pressure switches, thermostats, and emergency stops, forming part of a
layered safety chain that controls the burner or electric heating elements.

• Best suited for 3–4.5 GPM machines drawing from a gravity or float tank.
• Mounts in the suction line where pump inlet vacuum can be measured accurately.
• Works in combination with flow, pressure, and temperature switches to protect the system.
• Can switch burner primaries, gas or fuel solenoids, contactors, and safety relays within rated load.

Typical wiring concept

• Line power routed through emergency stop, pressure switch, flow switch, and vacuum switch in series.
• Only when all safety devices are “made” does power reach the burner or heating control.
• Loss of water (no vacuum) immediately opens the MVVS2.5 and disables the burner circuit.

MVVS2.5 | Vacuum Switch 2.5, 580 PSI, 220V 16A

Typical Applications

Because it combines simple design with robust safety performance, the MVVS2.5
is widely used across commercial and industrial cleaning equipment where
bulk water tanks are common and pump protection is essential.

• Electric and gas-fired hot-water pressure washers fed from totes or overhead tanks.
• Cabinet-style parts washers that must verify water availability before heat is enabled.
• Trailer and skid-mounted rigs used by contractors and mobile wash crews.
• Industrial wash bays where equipment is frequently started and stopped throughout the day.
• Rental fleet machines where automatic low-water protection reduces pump failures and service calls.

Key Specifications – MVVS2.5 Vacuum Switch

• SKU: MVVS2.5
• Type: vacuum-actuated, normally-open safety switch.
• Vacuum setpoint: 2.5″ Hg (closes on vacuum).
• Recommended flow range: pressure washers approx. 3.0–4.5 GPM.
• Contacts: up to 16 A rating.
• Connection: 1/4″ FPT vacuum inlet / port.
• Max water temperature: about 131°F (55°C).
• Typical system limits: commonly paired with pumps to around 2,600 PSI and up to 6.7 GPM (check machine specs).
• Approximate weight: 1.25 lb.