The Problem You’ve Already Faced
- The compressor doesn’t switch off or won’t start automatically. The pressure switch diaphragm has worn out or the contacts have burned — the motor runs continuously until the circuit breaker trips, or won’t start at all. Replacing just the switch without the regulator and fittings is a temporary fix.
- Bought a switch but the thread doesn’t match. A G 1/2″ pressure switch won’t fit a reservoir with a G 1/4″ port, and vice versa. This block is G 1/4″ × 4 ports, covering the vast majority of 220V piston compressors up to 3 kW.
- The regulator won’t hold stable pressure. The regulator diaphragm has cracked — output pressure fluctuates instead of holding the set value. Replacing the complete assembly is faster and more reliable than hunting down a separate diaphragm.
- The gauge reads incorrectly or the needle won’t return to zero. After 2–3 years of operation, gauges on budget compressors lose accuracy. Both gauges in this set are new.
- The safety valve vents at normal pressure. The valve spring has weakened, the seal is worn. Valve replacement is included in this set.
Buying one complete assembly at once is cheaper and faster than replacing the switch, regulator, gauges and valve one by one.
What Is a Compressor Pressure Switch and How Does This Assembly Work
A pressure switch is an electromechanical relay that controls the compressor motor based on pressure in the receiver tank. When pressure drops below the lower threshold (P_min) the contacts close — the motor starts. When pressure reaches the upper threshold (P_max) the contacts open — the motor stops. The operator plays no manual role in this cycle.
Contents of the complete assembly:
- Pressure switch — electromechanical relay with pressure range adjustment screw; the integrated unloader valve releases pressure from the discharge port on shutdown, easing motor restart
- Pressure regulator — maintains stable output pressure regardless of tank pressure; adjustable by rotary knob from 2 to 8–10 bar
- Tank gauge — displays current pressure in the receiver (0–12 bar)
- Regulator gauge — displays output pressure after the regulator (0–10 bar)
- Safety valve — mechanically vents pressure when the set limit is exceeded (typically 8.5–10 bar), emergency protection for the receiver
- 2 quick-release couplers — standard G 1/4″ connectors for hose attachment to pneumatic tools
The four G 1/4″ ports (internal thread) distribute between all elements listed above, with no need for additional manifolds or tees.
Technical Specifications
| Parameter | Value |
|---|---|
| Supply voltage | 220–230 V / 50 Hz (single-phase) |
| Maximum contact current | 16 A |
| Maximum motor power | up to 2.2–3.0 kW |
| Inlet port thread (to receiver) | G 1/4″ internal |
| Number of ports | 4 × G 1/4″ F |
| Pressure switch adjustment range | 2–10 bar |
| Regulator adjustment range | 2–8 bar |
| Safety valve trip pressure | 8.5–10 bar |
| Tank gauge scale | 0–12 bar |
| Regulator gauge scale | 0–10 bar |
| Unloader valve | integrated, automatic |
| Coupler type | quick-release G 1/4″ |
| Compatibility | 220V piston compressors with G 1/4″ receiver port |
| Compatible brands | Fiac, Abac, Fubag, Garage, Patriot, Remeza, Aircast, Bejing, Elitech, Sturm, Metabo, Makita and equivalents |
| Unit of sale | 1 complete assembly |
💡 Expert tip: before installing the new assembly, check the condition of the check valve on the compressor discharge port. A worn check valve fails to hold air in the receiver on shutdown — pressure drops, the motor starts too frequently. A new pressure switch won’t solve the problem if the check valve is leaking. These are separate components, and a faulty check valve is often misdiagnosed as a pressure switch fault.
Cross-Reference by Brand
| Brand | Model | Voltage | Thread | Current | Note |
|---|---|---|---|---|---|
| Condor (Germany) | MDR 3/11 | 220 V | G 1/4″ | 16 A | Reference manufacturer; complete supply without regulator |
| Italtecnica (Italy) | PM/5 | 220 V | G 1/4″ | 16 A | Used on Fiac, Abac; regulator sold separately |
| Lefoo (China) | LF10 | 220 V | G 1/4″ | 16 A | OEM on many compressors — good price-to-service ratio |
| Krom Schröder | — | 220 V | G 1/4″ | 16 A | Less common, but reliable German quality |
⚠️ Important: this block is a pressure switch complete assembly with regulator and fittings. Most branded alternatives (Condor, Italtecnica) supply only the switch body without regulator, gauges or couplers — a like-for-like swap requires purchasing the remaining elements separately.
5 mandatory parameters to verify compatibility:
- Receiver thread — confirm the receiver port is G 1/4″, not G 1/2″ or G 3/8″. A 1/4″ block won’t fit a 1/2″ port without an adapter.
- Supply voltage — this block is rated for 220 V. Three-phase 380 V compressors require a different pressure switch.
- Motor current — maximum contact current is 16 A. Verify that the motor’s starting current does not exceed this value (starting current = rated current × 5–7).
- Pressure range — if your compressor is rated for 10 bar, confirm the switch upper threshold can be set to the required value.
- Unloader valve type — the integrated unloader releases pressure from the discharge port on shutdown. Confirm it is compatible with your pipework layout.
Why Acvatron SRL — 5 Solid Reasons
Technical Selection by Compressor Model
Tell us the brand and model of your compressor — we confirm this block will fit. If the receiver thread is G 1/2″ or a 380V block is needed — we’ll offer the right variant from stock.
Full Documentation
Every block ships with an invoice listing the product name and customs tariff code. For legal entities and enterprises — a complete document package for asset registration.
Stock in Chisinau
220V and 380V control assemblies for piston compressors are held in permanent stock. Same-day dispatch for orders placed before 14:00.
Ready-to-Install — No Modifications Required
The block is supplied fully assembled and tested — simply connect to the receiver and electrical supply. No need to select a regulator, gauges and valve separately and align threads.
Complete Piston Compressor Parts Stock
Beyond control assemblies — check valves, filters, belts, oil, piston rings. Everything for a complete compressor service or repair. One request — one supplier.
Applications
Compressor Repair and Reconditioning
- Replacing a failed pressure switch on Fiac, Abac, Fubag, Garage, Patriot compressors
- Upgrading older compressors with obsolete controls
- Assembling custom compressor units from ready-made components
Automotive Service and Tyre Fitting
- Pressure management on spray booth compressors
- Automatic air supply to pneumatic tools
- Tyre inflation pressure monitoring
Woodworking and Small-Scale Manufacturing
- Regulating feed pressure for spray guns and paint applicators
- Automatic compressor control on assembly posts
- Protecting pneumatic lines from overpressure
Construction and Domestic Use
- Managing garage or site compressors
- Automating small pneumatic systems
- Equipping new compressor installations
Expert Opinion
“The most common call I get is: the compressor won’t stop. They replace the pressure switch — no improvement. It turns out the problem was the check valve: air was leaking back from the receiver through the discharge port, pressure wouldn’t hold, and the switch kept restarting the motor. The new pressure switch is doing its job perfectly — pressure just drops again. I always say: when you replace the pressure switch, check the check valve at the same time. It’s a five-minute check that saves an hour of diagnostics. Second point — when fitting, don’t overtorque the G 1/4″ thread. The pressure switch body is die-cast, and excessive torque cracks it. Two to three wraps of PTFE tape and hand-tight with moderate force — that’s enough.”
Vitalie Bolucevski, Chief Engineer, Acvatron SRL — 15 years in the industry
Applicable standards and regulations:
- GOST 12.2.016 — safety of compressor equipment
- EN 60947-2 — circuit breakers (applicable to contact group)
- PED 2014/68/EU — pressure equipment (safety valve)
- ISO 1219 — pneumatic systems and components
How to Select the Right Pressure Switch for Your Compressor: 5-Step Guide
- Identify the receiver port thread. Remove the plug or measure the thread diameter: G 1/4″ (13.16 mm), G 3/8″ (16.66 mm) or G 1/2″ (20.96 mm). This block is G 1/4″.
- Check the supply voltage. Single-phase 220 V network — this block fits. Three-phase 380 V — a different pressure switch is required.
- Check the motor current. Find the rated current (A) in the compressor manual. Starting current is 5–7 times higher. Maximum contact current of this block — 16 A; sufficient for motors up to 3 kW at 220V.
- Determine the required cut-out pressure. Most domestic and semi-professional 220V compressors operate at 8–10 bar. This block’s adjustment range — 2–10 bar; confirm the required pressure falls within range.
- Decide: complete assembly or switch only. If the regulator, gauges and valve are in working order — replacing just the switch is correct. If all the controls are worn or the compressor history is unknown — the complete assembly is more cost-effective and reliable.
FAQ
❓ What is the difference between a pressure switch and a pressure regulator?
A pressure switch (pressostat) controls the compressor motor: it starts the motor when tank pressure drops below the lower threshold and stops it when the upper threshold is reached. A pressure regulator is a purely pneumatic device: it maintains stable output pressure to the tool regardless of tank pressure. In this assembly both devices are installed in the same housing and operate independently of each other.
❓ How do I set the compressor cut-in and cut-out pressure?
The cut-out pressure (upper threshold, P_max) is adjusted with the large bolt under the pressure switch cover: clockwise increases it, counterclockwise decreases it. The differential (gap between P_max and P_min) is adjusted with the small bolt. Standard setting for most 220V compressors: P_max = 8 bar, differential = 2 bar (P_min = 6 bar). Monitor results on the tank gauge.
❓ Where can I buy a 220V pressure switch with regulator for a compressor in Moldova?
The 220V G 1/4″ control assembly with pressure regulator, gauges, safety valve and 2 quick-release couplers is in stock at Acvatron SRL, Chisinau. Compatible with single-phase piston compressors: Fiac, Abac, Fubag, Garage, Remeza and equivalents. Contact us at acvatron.md or WhatsApp.
