Mitsubishi Electric Ecodan PUZ-WM85VAA + FTC6

Compatibility

Compatible with EpiSensor Edge over Modbus through a MelcoBEMS MINI A1M+

Mitsubishi pairs PUZ-WM85VAA with FTC6 PAC-IF072B-E. The MelcoBEMS MINI A1M+ v1.03 manual lists that controller in Appendix B and marks applicable FTC6 registers in its Air-To-Water table. A1M+ provides Modbus TCP and RTU through a separate controller-connected gateway.

Use the published v1.03 map as a best-effort starting point for an installed A1M+ and compare values with the FTC6 controller. Record gateway and controller revisions and reconcile any address differences during commissioning. This guide covers read-only monitoring; preserve the existing heating, DHW and grid-signal controls.

Connect it with

• Modbus Interface ZMB-3X From €399 ex VAT Configure
• Gateway ZGW-20 From €899 ex VAT Configure
• Evaluation Gateway on a Raspberry Pi Edge with one device licensed Free Set up

Models

Specifications

Mitsubishi's product sheet identifies PUZ-WM85VAA(-BS) as a single-phase R32 monobloc with 8.5 kW heating capacity at A-7/W35. This is an outdoor-unit specification at a defined test condition, not a whole-system output guarantee.¹

Exact outdoor unit

PUZ-WM85VAA; verify any -BS suffix on the installed nameplate¹

Declared heating point

8.5 kW at A-7/W35; 3.27 kW power input; COP 2.60 at that point¹

FTC6 pairing

PAC-IF072B-E controller compatibility matrix includes PUZ-WM85(V/Y)AA(-BS)²

Meter inputs

IN8/IN9 electricity pulses; IN10 heat-meter pulses, subject to commissioned meter and controller settings^2, 3

Grid-signal inputs

IN11/IN12 contact combinations; external control design and installer approval required³

Monitoring accessory

MelcoBEMS MINI A1M+: Modbus TCP at port 502 or configured Modbus RTU; FTC6 register applicability is shown in the ATW table⁴

Interface

Documented measurements and integration boundaries for Ecodan PUZ-WM85VAA + FTC6.

• The A1M+ Air-To-Water map marks signed flow temperature at zero-based holding address 101 (Modicon 40102) and signed return temperature at 103 (40104) as read-only for FTC6. Read with FC03 and divide each signed 16-bit value by 100 to obtain °C.
• Signed outdoor ambient temperature is holding address 99 (40100), scaled by 10 rather than 100. Keep scaling with each point definition; it differs from the flow and return rows.
• A1M+ supports Modbus TCP at TCP port 502. For RTU, switch 7 selects Modbus and switch 6 ON selects 9600 baud/no parity; data bits are fixed at 8 and stop bits at 1. Record the configured slave address from the gateway settings.
• For an RTU-only installation, untick the A1M+ setting No Network Self Reboot. The manual says it otherwise reboots after roughly 20-30 seconds without an Ethernet link. Save changes and reboot as instructed before polling.
• FTC6 IN8 and IN9 accept electricity-meter pulses and IN10 accepts heat-meter pulses. Record meter coverage, pulse weight and polarity. Meter totals and controller temperature readings serve different purposes.
• IN11 and IN12 encode four Smart Grid Ready states during heating or DHW operation. Keep these contacts under the commissioned control design while establishing monitoring.
• Use independently measured delivered heat and all included electrical loads over matching intervals for site COP or seasonal performance. Controller temperatures help explain operation; the declared product COP describes a laboratory test point.

Setup

1. Identify the installed pair

   Record the PUZ-WM85VAA outdoor nameplate, PAC-IF072B-E controller and any hydrobox or cylinder identity. Note the controller and A1M+ software revisions.

2. Fit and configure A1M+

   Use the supplied CN105/CN92 controller lead and plan any existing accessories sharing that socket. Check that AC ACK flashes for valid controller communication. Set the gateway network or RTU address and keep it in application mode.

3. Read a flow temperature

   Use FC03 at zero-based holding address 101, length one. Decode a signed 16-bit integer and divide by 100 °C. Compare it with the local FTC6 flow-temperature display; add return temperature at 103 and outdoor temperature at 99 after that check.

4. Define the measurement boundary

   Identify heat and electricity meters with matching time intervals. Include pumps and auxiliary heaters in the declared COP boundary, and record any meter pulses wired into FTC6.

5. Check data during normal operation

   Record timestamps and compare changing flow and return temperatures with the controller. Check communications LEDs and missing samples. For RTU-only operation, disable No Network Self Reboot in A1M+ settings.

6. Preserve commissioned controls

   Keep heating mode, DHW, frost protection and SG Ready contacts in their existing commissioned configuration. Design command limits and local override separately before introducing flexibility control.

Common questions

How can Edge monitor this FTC6 heat pump over Modbus?

Fit a compatible MelcoBEMS MINI A1M+ to PAC-IF072B-E. The gateway exposes Modbus TCP and RTU, and its manual supplies an FTC6 Air-To-Water map. Start with flow temperature at FC03 zero-based address 101, signed /100 °C, and compare the read with the controller.^2, 4

What do the FTC6 IN8, IN9 and IN10 terminals do?

They accept pulses from up to two electrical meters and a heat meter. The installer must specify the meter boundary and pulse setting; a terminal listing does not prove an external telemetry feed or system-wide COP.³

Does Smart Grid Ready make this a VPP-dispatchable heat pump?

FTC6 provides four Smart Grid Ready contact states for heating and DHW. A flexibility design should define permitted states, schedule limits, local override and fallback with the installer, then measure the resulting electrical response.³