Pichler PKOM4

Name: Pichler PKOM4
Brand: Pichler
SKU: 5ffeed2f-d02b-41b7-94f3-ad8699b6c008

Heat pump combination unit for ventilation, heating, cooling and hot water in low energy homes.

The Pichler PKOM4 is a heat pump combination unit that ventilates, heats, cools and produces hot water in low energy and passive houses. This Modbus RTU template reads all temperatures, air flows, power, energy and errors and lets you write the operating mode, room and hot water setpoints and ventilation level from ModbusCloud.

Protocol: Modbus RTU
Connection: RS485, 19200 baud
Registers: 93, read and write

Brand: Pichler
Key readings: Room temperature · Supply and extract air temperature · Outdoor air temperature · Hot water tank temperature · Air flow · Electrical power · COP · CO2 and humidity
Available commands: Operating mode · Room setpoints · Hot water setpoint · Ventilation level
Compatible models: PKOM4
Last updated: 23 October 2026

Registers (93)

93 read, 50 write

Name	Unit	Access
Operating Mode		Read and write
Room Temperature Measurement		Read and write
Auto Summer/winter Changeover	°C	Read and write
Active Cooling		Read and write
Setpoint Room Normal	°C	Read and write
Setpoint Room Lowered	°C	Read and write
Setpoint Room Vacation	°C	Read and write
Room Sensor		Read and write
Setpoint Room Active Cooling	°C	Read and write
Min. ODA Temp. To Enable Cooling	°C	Read and write
Automatic Room Temperature		Read and write
SUP Setting Ventilation Level 1	m³/h	Read and write
SUP Setting Ventilation Level 2	m³/h	Read and write
SUP Setting Ventilation Level 3	m³/h	Read and write
SUP Setting Ventilation Level 4	m³/h	Read and write
ETA Balance		Read and write
Selected Ventilation Level		Read and write
Min. SUP Temperature Cooling	°C	Read and write
Max. SUP Temperature Heating	°C	Read and write
CO2 Concentration To High	ppm	Read and write
Relative Humidity To High	%RH	Read and write
Relative Humidity To Low	%RH	Read and write
Max. Control Voltage Duct Heater	V	Read and write
Setpoint DHW	°C	Read and write
Setpoint DHW - Ecotarif	°C	Read and write
E-heater DHW		Read and write
Eco Tarif		Read and write
Legionella Protection Function		Read and write
Legionella Protection Interval		Read and write
Setpoint Room Temp. Heating Circuit	°C	Read and write
Max. ODA Temperature To Enable Heating	°C	Read and write
Reset Errors		Read and write
Operating Hours DHW_compressor	h	Read and write
Operating Hours HC_compressor	h	Read and write
Operating Hours ETA Fan	h	Read and write
Operating Hours ODA Fan	h	Read and write
Operating Hours K5	h	Read and write
Operating Hours E-heater	h	Read and write
Operating Hours 4-way Valve	h	Read and write
Operating Hours Filter AUL & ABL	h	Read and write
DHW Release		Read and write
DHW Timer Start Hour		Read and write
DHW Timer Start Minute		Read and write
DHW Timer Stop Hour		Read and write
DHW Timer Stop Minute		Read and write
Heating Circuit Release		Read and write
Heating Circuit Timer Start Hour		Read and write
Heating Circuit Timer Start Minute		Read and write
Heating Circuit Timer Stop Hour		Read and write
Heating Circuit Timer Stop Minute		Read and write
Act. Fan Speed ETA	rpm	Read
Act. Fan Speed ODA	rpm	Read
Act. Room Temperature	°C	Read
Air Flow SUP	m³/h	Read
Air Flow ETA	m³/h	Read
Electr. Power DHW Comp.	W	Read
Electr. Power HC Comp.	W	Read
Electr. Power PCB+Fans	W	Read
Cooling Energy 12 Months	kWh	Read
T2 Display	°C	Read
Ventilation Energy 12 Months	kWh	Read
Booster E-heater Remaining Time	min	Read
Error Bits 0 To 15		Read
Error Bits 16 To 31		Read
Error Bits 32 To 47		Read
Error Bits 48 To 63		Read
Heating Capacity	W	Read
DHW Energy 12 Months	kWh	Read
SCOP Heat Pump 12 Months		Read
COP Actual		Read
PV Input		Read
Heating Energy 12 Months	kWh	Read
Energy Consumption 12 Months	kWh	Read
T1 Supply Air	°C	Read
T3 Outdoor Air	°C	Read
T4 Exhaust Air	°C	Read
T7 Extract Air	°C	Read
T9 Duct Heater/solar Collector	°C	Read
T20 DHW Tank Temperature	°C	Read
T21 DHW Tank Temperature	°C	Read
Status Relais		Read
Act. Capacity Compressor HC	%	Read
Status System		Read
Status Fan ODA		Read
Act. Ventilation Level SUP		Read
Active Setpoint Room Temperature	°C	Read
Status Fan ETA		Read
Active Setpoint DHW	°C	Read
Status Bypass		Read
T40 Sensor External	°C	Read
CO2 Concentration	ppm	Read
Relative Humidity	%RH	Read
External Pump	%	Read

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If a device is not in the library yet, we build the template for free as soon as we have the register data.

Use cases

Show room, supply air and tank temperatures with the air flows of a PKOM4 on one dashboard.
Send an email alert when one of the error words changes from zero.
Keep 365 days of history of COP and energy for heating and hot water to check the heat pump.
Change the operating mode or room setpoint remotely when residents are away on vacation.
Raise the ventilation level when the CO2 value stays above the threshold you set.

Installation

Connect RS485 A and B of the PKOM4 to the RS485 port of the ModbusCloud Gateway and terminate both ends of the bus.
Check address, baud rate and parity in parameters 208 to 210 on the unit; from the factory it uses address 41, 19200 baud and even parity.
In ModbusCloud, add a Modbus device on the Gateway with the same address and serial settings, then import this template.
Check that the room temperature, outdoor air temperature and air flows arrive with plausible values.

Things to watch for

The PKOM4 does not answer on the RS485 bus. What should I check?

From the factory the unit answers on address 41, not 1, at 19200 baud with even parity. Match these settings, swap A and B if nothing comes back, and terminate only the two ends of the bus.

Why do temperatures look a hundred times too large?

Temperatures and temperature setpoints are sent with two decimals, so 2150 means 21.50 °C. The template applies that scale. If a value still looks wrong, check that the register uses the scale from the template and was not changed by hand.

Which registers can I write from ModbusCloud?

All setpoints in the holding registers: operating mode, room and hot water setpoints, ventilation levels and air volumes, thresholds, timers and the error reset. Stay inside the range given in each register comment and read the value back after writing.

How do I see which error is active?

Four registers hold 64 error bits, 16 per register. A value of zero means no error. The meaning of each bit is shown on the unit display; set an alert on any value above zero so you know when to look.

Can several units share one RS485 line?

Yes. Give every unit its own address with parameter 208 and use the same baud rate and parity on all devices. Run the bus as one line and terminate both ends.

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