Common mistakes — Blue Airco gateway

General problems of this gateway family (LED codes, box invisible on the bus, firmware update) are in Common mistakes. This chapter is what goes wrong with the Blue Airco side specifically.

Nothing at all on device/21/…

A port publishes only while a unit is answering it. No answer, no topic — not even zeros, and no MUXEN identity for that port at all. Work down this list in order:

Likely cause	How to tell	Fix
The unit is switched off	its own panel is dark	power it up; the gateway needs the unit's controller running, not just the line wired
A and B swapped, or no common ground	total silence, other ports fine	check the RS-485 pair and the ground on that port
The unit is not at Modbus address 1	silence on one port only	every port of this gateway talks to address 1 and nothing else. Set the unit to 1
Two units on one line	silence or nonsense on that port	one unit per port. Move the second one to a free port
The unit is not at 9600 8N1	total silence rather than errors	the ports are fixed at 9600 8N1 by the firmware. It cannot be changed by an overlay, a parameter or a command
Wrong firmware in the box	ProductId is not 010010028	check it, and load the right image

It worked, then that unit disappeared

A port drops its unit after 30 seconds without a valid answer. It then stops publishing, takes its device off the air and starts probing again — while keeping the instance number, so the unit comes back on the same number and no other port can take it in the meantime.

A machine that flickers in and out of the boat's screens is a unit whose answers are not arriving reliably — suspect the RS-485 pair, the ground or the connector, not the gateway.

While a unit is considered gone, commands from the boat are discarded silently. Nothing is queued and nothing is retried.

The unit switches itself off and nobody asked

That is the battery supervision doing its job. The gateway watches the park the unit is bound to and forces the unit off whenever that park reports overload, low battery or off, or a charge below MinSocToWork percent.

Likely cause	How to tell	Fix
Bound to a park that is not on the bus	the unit will not stay on at all, whatever you do	a park with no battery reporting reads as off. Bind it to a real park, or set BindToParc to 255 (standalone)
The park is genuinely low	the boat's battery pages agree	nothing to fix here; raise MinSocToWork only if you know what you are doing
MinSocToWork too high	the unit stops at a charge you consider normal	lower it

A unit left standalone (BindToParc = 255, which is what a port takes the first time a unit is detected on it) is never stopped for an electrical reason.

A command does nothing

Likely cause	How to tell	Fix
The gateway is not hearing the unit	no life topic in the last few seconds	see the first table — commands are dropped while the unit is absent
The battery supervision is switching it back off	it starts, then stops again within a second or two	see the section above
The set point is outside the unit's window	runningMode reacts, tempSetPoint does not	see the windows in Reference — Blue Airco gateway; a value outside them is dropped in silence
An EVO unit is refusing every write	nothing at all reacts, and the unit is in fault	while an EVO unit raises its "operation prohibited" flag it rejects every write, and the gateway does not even try. Clear the fault on the unit's panel
Wrong instance	another air conditioner moved instead	check the instance in the topic

Only two commands exist: {"command":0,…} for on/off and {"command":1,"parameter":<°C>} for the set point.

I cannot set the mode or the fan speed

They are not carried. This gateway reports the mode and the fan speed and never writes them. Set them on the unit's own panel. Keep those buttons off any screen page that drives a Blue Airco.

{"command":0,"parameter":2} switches the unit on

parameter 2 means auto on the MUXEN HVAC device. Neither Blue Airco generation has an automatic on/off to drive, so this gateway treats it exactly like on. Use 0 and 1.

Two air conditioners report the same values

Out of the box a port takes the number of the port as its instance — 0 to 3 for serial 1 to 4 — and it only checks the other ports of the same box. A second Blue Airco gateway installed straight out of its box therefore publishes HVAC 0 to 3 alongside the first, and the boat sees one air conditioner whose readings jump between two machines.

Number the second box before connecting it to the MUXEN bus, or straight away after; see step 5 of Commissioning.

muxen-uds -i can0 scan

Function 21 must appear once per real air conditioner.

uid --scan lists my box several times

Expected. Every device this gateway publishes answers the UID request with the box's own UID, so one box shows up once for its I/O device and once per air conditioner it has detected. Tell them apart by the function and instance columns.

uid --instance will not renumber an air conditioner

That command works through the parking address, and the HVAC devices of this gateway never park: they take a real instance the moment a unit answers. Use one of the two methods in step 5 of Commissioning instead. uid remains the right tool for the box's own I/O device (function 17).

No alarm ever appears

Known limitation of this version: only the EVO units report faults. A pre-EVO unit has no fault word for the gateway to read, so no alarm is ever raised for it and its faults stay on its own panel.

On an EVO unit, four of the drive-board faults have no MUXEN equivalent and are not reported either; the full list is in Reference — Blue Airco gateway. The unit's own panel is the authority. An alarm on the boat is a reliable signal that something is wrong, but read the E-code on the machine before ordering a part.

The temperatures are whole degrees

They are. An EVO unit measures in tenths of a degree, the MUXEN HVAC device carries whole degrees, and the gateway rounds to the nearest one. A set point of 22.5 °C entered on the unit's panel is reported to the boat as 23 °C, and the boat can only ask for whole degrees back.

RemoteAddr, MinSetPoint and MaxSetPoint do nothing

They are part of the MUXEN HVAC parameter set but this gateway does not use them. The Modbus address is fixed at 1 and the set-point windows come from the unit's own protocol. Changing them has no effect; do not build a commissioning procedure on them.

The box's own relay and analog input never appear

Symptom	Cause	Fix
nothing on device/17/…	the I/O device ships not addressed (InstanceNum = 255)	give it an instance number, and set EnGenIo to 1
still nothing	EnGenIo is still 0	it is the switch of the whole device, not of one channel

I changed a setting and nothing happened

Parameters are read once, at startup. Always write with --reboot:

muxen-uds -i can0 -F 21 -I <instance> writeconfig --name MinSocToWork --value 30 --reboot

The one exception is the port allocation routine of step 5, which takes effect immediately.

I swapped a unit for one of the other generation

Nothing to do. When a port loses its unit it forgets which register map that unit spoke, and probes both again. The replacement is picked up on its own within a couple of seconds of answering, on the same instance number as before.

After a factory reset

A reset is addressed to one device at a time, so run it once per air conditioner and once for the box's own I/O device, and mind which of the two resets you ask for:

	Effect
Reset the configuration	every parameter of that device goes back to its default — BindToParc, MinSocToWork, RemoteCmdEqn, EnGenIo — and the instance number is kept
Reset the device address	the instance number goes back to its default: 255 for the I/O device, not configured for an air conditioner

A port whose instance number has been reset takes the number of the port again on the next start, so a box that had been renumbered comes back publishing HVAC 0 to 3. Do that before the box goes back on a bus that already has an HVAC 0.