If you are replacing a phased-out Belimo EP050R+MP-N, the EP050R2+BAC-N is the current DN50 EPIV option to evaluate. It keeps the same nominal voltage, nominal flow and pressure class, and it can operate in an MP-Bus compatibility mode for legacy replacement work. It is not, however, an identical drop-in assembly. The pipe connections, conductor count, theoretical Kvs value and available protocols differ, so the retrofit must be checked against the installed valve, wiring and BMS configuration before it is ordered.
Confirm the Exact Legacy Model First
The phased-out Belimo datasheet is for EP050R+MP-N. Site labels and maintenance records often shorten this to EP050R+MP, but the suffix matters when a supplier cross-references the assembly. Photograph the full nameplate and record the valve connection, cable, configured maximum flow and existing MP address before disconnecting anything.
EP050R+MP-N vs EP050R2+BAC-N
| Verification point | EP050R+MP-N (phased out) | EP050R2+BAC-N (current) |
|---|---|---|
| Valve type | DN50, 2-way EPIV, internal thread | DN50, 2-way EPIV, internal and external thread |
| Nominal flow V’nom | 22.68 m³/h (6.3 l/s) | 22.68 m³/h (6.3 l/s) |
| Theoretical Kvs | 32.0 m³/h | 30.4 m³/h |
| Pressure class | PN25 | PN25 |
| Nominal voltage | AC/DC 24 V | AC/DC 24 V |
| Communication | MP-Bus or conventional control | BACnet MS/TP, Modbus RTU, MP-Bus or conventional control |
| Supply/control cable | 1 m, 4 x 0.75 mm² | 1 m, 6 x 0.75 mm² |
| Glycol range | Up to 50% by volume | Up to 60% by volume |
| Maximum flow adjustment | 30-100% of V’nom | 25-100% of V’nom |
| Additional measurements | Flow | Flow, fluid temperature and glycol content |
The values above come from Belimo’s official product datasheets. The corrected Kvs row is important: both assemblies have the same nominal flow, but their theoretical Kvs values are not identical. That difference does not automatically prevent a replacement because an EPIV regulates measured flow, but it does mean the engineer should verify available differential pressure and the intended V’max instead of relying on pipe size alone. See the BuildMEP Cv/Kv guide for the hydraulic context.
Why This Is Not an Automatic Drop-In Swap
- Mechanical connection: the legacy unit is documented with an Rp 2 internal thread. The current unit has Rp 2 internal and G 2 1/2 external connections. Belimo lists the ZREV50F pipe connector as an accessory for the current DN50 assembly. Confirm the installed unions and available straight length before assuming an adapter is required or unnecessary.
- Wiring: the legacy assembly uses a four-conductor supply/control cable; the current assembly uses six conductors. Do not transfer wires by colour or terminal position from memory. Use the current wiring diagram and the existing control narrative.
- Control mode: the current product supports BACnet MS/TP, Modbus RTU, MP-Bus and conventional analogue control. Adding protocols does not mean the existing controller can use them without configuration and RS-485 wiring.
- Hydraulics: verify V’nom, required V’max, available differential pressure, glycol concentration and fluid temperature. The current datasheet lists Δpmax 350 kPa and recommends 200 kPa for low-noise operation.
- Installation geometry: Belimo permits upright-to-horizontal mounting relative to the spindle, not a hanging spindle-down position. Flow direction must follow the housing arrow.
Retrofit Workflow
1. Capture the Existing Configuration
Record the complete model number, voltage, control signal, MP address, V’max setting, design flow, pipe connection, installation orientation and BMS point mapping. Save trend data for flow and command before shutdown where possible. This creates a commissioning baseline instead of relying on a visual replacement alone.
2. Verify Hydraulic Duty
Confirm that the required maximum flow is within the new valve’s adjustable range and that the available differential pressure is adequate. Keep the documented V’nom of 22.68 m³/h separate from the project V’max setting: V’nom is the valve’s nominal capacity, while V’max is the configured project flow at full command.
3. Check Pipework and Access
Compare the existing union and thread arrangement with the current drawing. Allow for the ZREV50F connector only where the installed arrangement requires it. Belimo recommends installation in the return, a suitable strainer, correct flow direction and an inlet calming section of at least 5 x DN ahead of the flow sensor for stated measurement accuracy.
4. Select the Control Strategy
For an existing MP-Bus system, use the documented MP compatibility mode only after confirming the legacy client and addressing. Belimo states that this mode is for replacement in an existing MP-Bus system and should not be used for new projects. For a new BACnet or Modbus integration, confirm baud rate, addressing, polarity, grounding and the BMS object/register schedule before commissioning. The BuildMEP control-signal guide explains the protocol choices.
5. Rewire From the Current Datasheet
The new six-conductor cable is not a colour-for-colour continuation of the legacy four-conductor cable. Verify 24 V supply capacity and isolate the transformer before work. For BACnet MS/TP or Modbus RTU, follow RS-485 rules; Belimo notes that supply and communication are not galvanically isolated, so device COM and ground must be coordinated correctly.
6. Configure and Commission
Use Belimo Assistant 2 to set V’max, control mode and feedback. Confirm the valve synchronises, the command drives the expected flow, feedback is scaled correctly and the BMS receives no sensor or communication alarms. The current EPIV can fall back from flow control to position control during a flow-sensor fault, so include a sensor-fault check in the sequence review.
7. Record the Handover Values
| Commissioning record | Value to capture |
|---|---|
| Installed model and serial number | Full label photograph |
| Configured V’max | m³/h and percentage of V’nom |
| Control mode | Analogue, MP-Bus, BACnet MS/TP or Modbus RTU |
| Address and communication settings | Address, baud rate and parity where applicable |
| Command / measured flow test | 0%, intermediate and 100% command points |
| Feedback mapping | Flow, position or temperature signal |
| Fluid and glycol | Operating temperature and glycol percentage |
| Final alarms | No active sensor, actuator or communication fault |
Common Replacement Mistakes
- Ordering from the shortened EP050R+MP name without confirming the full EP050R+MP-N label.
- Calling the new assembly a direct drop-in because DN, PN and V’nom match.
- Repeating the old Kvs value for the new valve or assuming both Kvs values are 30.4 m³/h.
- Reusing wire colours without checking the new six-core wiring diagram.
- Enabling MP compatibility mode on a new project rather than using the current native protocol options.
- Ignoring the required inlet section, flow arrow, strainer or mounting orientation.
- Leaving the old V’max undocumented and accepting factory settings at handover.
Frequently Asked Questions
Is EP050R2+BAC-N the replacement for EP050R+MP-N?
It is the current DN50 EPIV option with a documented MP compatibility mode for replacement of former EP..R-(K)MP devices. Final suitability still depends on the installed connections, hydraulic duty, wiring and control configuration.
Are the two valves hydraulically identical?
No. They share DN50, PN25 and V’nom 22.68 m³/h, but the official datasheets list theoretical Kvs values of 32.0 m³/h for EP050R+MP-N and 30.4 m³/h for EP050R2+BAC-N. Verify available differential pressure and project V’max.
Is ZREV50F always required?
No. Belimo lists ZREV50F as a DN50 pipe-connector accessory for the current valve. Whether it is required depends on the installed union and thread arrangement. Confirm dimensions and connections on site before ordering.
Can the existing MP-Bus controller remain?
Potentially. The current unit can be configured in MP compatibility mode so an existing MP client recognises it as a former EPIV device. Belimo explicitly reserves that mode for replacement work, not new projects.
