The Belimo 01APS-501 is a differential pressure switch for monitoring overpressure, vacuum, and differential air pressure or other non-combustible, non-aggressive gases in HVAC and energy management applications. It has a measuring range of 0.80 to 4.00 inch WC (200 to 1000 Pa), setpoint adjustment with automatic reset, and an SPDT contact.
Repeating accuracy is ±1%, min. ±0.02 inch WC (5 Pa) and the switching differential is 100 Pa. The contact is rated max. 1.0 A resistive or 0.4 A inductive at AC 250 V. The switch is cULus and ETL listed (UL 508, CSA C22.2 No. 14), with a NEMA 13 / IP54 housing.
Filter and fan monitoring in air ducts, and overpressure or vacuum monitoring in HVAC and energy management applications, with a measuring range of 0.80 to 4.00 inch WC (200 to 1000 Pa).
Buying in volume? The Belimo 01APS-501.1 is the Belimo multipack of 45 pcs for this range.
Key Features
Adjustable Setpoint, Automatic Reset
The switching setpoint is adjusted with a screwdriver; measuring range 0.80 to 4.00 inch WC (200 to 1000 Pa). The contact resets automatically, with a 100 Pa switching differential.
SPDT Contact
Screw terminals 1 (NC), 2 (NO) and 3 (COM). Rated max. 1.0 A resistive or 0.4 A inductive, such as a relay or contactor coil, at AC 250 V.
±1% Repeating Accuracy
Repeating accuracy of ±1%, min. ±0.02 inch WC (5 Pa), with a burst pressure of 40 inch WC (10 kPa).
Long Service Life
Rated for min. 1,000,000 switching operations, with long-term stability of ≤±15% deviation over 250,000 operations/cycles acc. EN 1854.
NEMA 13 / IP54, cULus and ETL Listed
PA 6.6 base with PS top cover. cULus and ETL listed to UL 508 and CSA C22.2 No. 14, CE marked, IEC/EN 60730-1.
Installation Parts Included
Ships with 2 m of PVC tube, two plastic duct connectors, screws and a 1/2" NPT conduit adapter.
ZOT Supply is an authorized distributor of Belimo products.
Technical Specifications
| Specification | Detail |
|---|---|
| Product Type | Differential pressure switch with adjustable setpoint and automatic reset |
| Measured Value | Differential pressure |
| Measuring Fluid | Air, non-combustible and non-aggressive gases |
| Measuring Range | 0.80 to 4.00 inch WC (200 to 1000 Pa) |
| Repeating Accuracy | ±1%, min. ±0.02 inch WC (5 Pa) |
| Switching Differential | 100 Pa |
| Burst Pressure | 40 inch WC (10 kPa) |
| Contact | SPDT |
| Terminals | 1 = NC, 2 = NO, 3 = COM |
| Contact Rating | Max. 1.0 A resistive, 0.4 A inductive, at AC 250 V |
| Reset | Automatic |
| Service Life | Min. 1,000,000 switching operations |
| Long-Term Stability | ≤±15% deviation over 250,000 operations/cycles acc. EN 1854 |
| Electrical Connection | Terminals for wire 0.5 to 1.5 mm² |
| Cable Entry | Cable gland with strain relief, Ø 6 to 8 mm (1/2" NPT conduit adapter included) |
| Pressure Connections | P1 (+) and P2 (-), Ø 0.24 in. (6 mm) |
| Mounting Hole Pattern | 2.56 x 2.56 in. |
| Height | 2.25 in. (57.2 mm) |
| Installation Position | Vertical with the pressure connections pointing down is recommended; switching pressure specifications refer to this position. Horizontal with the AMP connecting lugs pointing up raises the switching point by approx. 20 Pa. Upside-down mounting is not permitted. |
| Housing Material | Bottom part: PA 6.6; top cover: PS |
| Degree of Protection | NEMA 13, IP54 |
| Ambient Humidity | Max. 95% RH, non-condensing |
| Ambient Temperature | -4 to 140°F (-20 to 60°C) |
| Fluid Temperature | -4 to 140°F (-20 to 60°C) |
| Storage Temperature | -40 to 185°F (-40 to 85°C) |
| Listings | cULus listed and ETL listed; UL 508, CSA C22.2 No. 14 |
| Certification IEC/EN | IEC/EN 60730-1 |
| EU Conformity | CE marking; CE according to 2014/35/EU (Low Voltage Directive) |
| Quality Standard | ISO 9001 |
| Weight | 0.26 lb (0.12 kg) |
| Package | Single unit |
| Country of Origin | Made in Germany |
| Warranty | 5 years |
| Manufacturer | Belimo |
| Manufacturer Part Number | 01APS-501 |
Specifications per Belimo technical data sheet 01APS-5.. (en-us, 2024-07-25) and installation instructions 71932-00001.B (2021-03). Reviewed October 2026.
Scope of Delivery
- Belimo 01APS-501 differential pressure switch
- PVC tube, 2 m
- 2 x duct connectors (plastic)
- Screws
- 1/2" NPT conduit adapter
Documentation
Belimo 01APS-5.. Technical Data SheetBelimo 01APS Installation Instructions (US)Belimo Sensors BrochureFrequently Asked Questions
What is the Belimo 01APS-501?
The Belimo 01APS-501 is a differential pressure switch with a measuring range of 0.80 to 4.00 inch WC (200 to 1000 Pa). It switches an SPDT contact at an adjustable setpoint and resets automatically.
What are the range, accuracy and switching differential of the 01APS-501?
Measuring range 0.80 to 4.00 inch WC (200 to 1000 Pa), repeating accuracy ±1%, min. ±0.02 inch WC (5 Pa), switching differential 100 Pa, and burst pressure 40 inch WC (10 kPa).
How is the 01APS-501 wired?
The SPDT contact has three screw terminals: 1 = NC, 2 = NO and 3 = COM. Wire COM (3) with NO (2) or with NC (1) as the control circuit requires. Terminals accept 0.5 to 1.5 mm² wire. The contact is rated max. 1.0 A resistive or 0.4 A inductive at AC 250 V; inductive loads such as relay or contactor coils are limited to 0.4 A.
How do I connect the 01APS-501 for filter or fan monitoring?
For filter monitoring, connect P1 on the upstream (inlet) side of the filter and P2 on the downstream side. For fan monitoring, connect P2 on the inlet side of the fan and P1 on the discharge side. Locate each duct tap 0.1 to 0.2 x d from the filter or fan, where d is the duct dimension. Each duct tap is a 7 mm (0.276 in.) hole with 2 x 2.2 mm (0.087 in.) screw holes.
What is the recommended mounting position for the 01APS-501?
Vertical with the pressure connections pointing down is recommended; switching pressure specifications refer to this position. Mounted horizontally with the AMP connecting lugs pointing up, the switching point is approx. 20 Pa higher. Upside-down mounting is not permitted.
Can the 01APS-501 be used with gases other than air?
Yes, for non-combustible and non-aggressive gases. Fluid and ambient temperature limits are -4 to 140°F (-20 to 60°C).
What is included with the 01APS-501?
A 2 m PVC tube, two plastic duct connectors, screws and a 1/2" NPT conduit adapter.
How do I choose between the 01APS pressure ranges?
Select by measuring range. Measuring range, repeating accuracy and switching differential by model: 01APS-50R: 0.08 to 1.20 inch WC (20 to 300 Pa), ±5%, 10 Pa; 01APS-50U: 0.20 to 2.00 inch WC (50 to 500 Pa), ±2.5%, 20 Pa; 01APS-501: 0.80 to 4.00 inch WC (200 to 1000 Pa), ±1%, 100 Pa; 01APS-504: 2.00 to 10.00 inch WC (500 to 2500 Pa), ±1%, 150 Pa.
- Sensor Type:
- Differential Pressure Switch
- Pressure Range:
- 0.80 to 4.00
- Accuracy:
- ±1% repeatability (min. ±0.02 inch WC / 5 Pa)
- Switch:
- (1)SPDT
- Switch Rating:
- 1.0 A @ 250 VAC
- Reset:
- Automatic
- Output Signal:
- SPDT Switch (no analog signal)
- Display:
- No Display
- Setpoint:
- Adjustable Setpoint
- Override:
- No Override
- Supported Protocols:
- None
- Enclosure:
- NEMA 13 Enclosure
1 Review Hide Reviews Show Reviews
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Simple and effective
I have ordered 32 of these for use in a manufacturing site that has a waste extraction system connected to their printing equipment. These are being placed on the pickup tube at each machine and using the signal to indicate to the operator if they have suction and can run or not. These are simple to use and very straight forward. We are connecting them to an LED indicator and using the power from the machine.
