Webasto diesel heater control question.

[scotia]

Yes, that would work that way.
I prefer to do it by removing pins 8 and 9 on the ecu plug though and making the connection there. ( that way you can just replace the pins if you wish to revert to the original and not have to rejoin wires) Although this would mean that you have to access the heater to unplug the loom though rather than accessing it near the controller.

ah yes ok, i see. Easier for me to do it at the controller end as i dont have a lift at the house - did the heater install at a mates..!

 

[Trudy Danby]

Hi
I have s question re Webasto heaters. I have a webasto heater fitted in my T6. I set the thermostat and the heater works however, I am not sure if it’s working correctly, when it reaches temperature the fan keeps running. I can understand that it does this whilst the heater cools but the fan runs all night, is that correct?

 

[oldiebut goodie]

What model heater?
Are you sure that you are talking about a thermostat as thermostats have not been used on Webasto heaters for donkey's years. Current models use a rheostat, the heater ecu compares the air temperature entering the heater with the set temperature of the rheostat. The air will always be cooler entering the heater, if mounted at floor level, than that which you feel at mid-height in the vehicle, if you want it to behave more like a thermostat and sense the mid-height temperature you have to fit an external temperature sensor at that height. ( Or set the rheostat at a lower temperature setting than you are currently using ). The heater varies the heat output ( between 0.9Kw and 2Kw on a 2Kw model, 1.5Kw and 3.5Kw on a 3500 and 1.5Kw and 5Kw on a 5Kw one - and so on) as the intake air temperature reaches the setpoint of the rheostat - how do you know when it has reached temperature as you see it?

 

[richi]

Yes - it is the same plug on the ST and STC and the same pins 8 and 9 that it connects to. It is only very recent ST models that will be able to use the Multicontroller. The manual says heaters after 04/2015 shouldn't need the Unibox.
The Multicontroller is a strange beast in that it does have a temperature sensor built in but that information doesn't appear to be transmitted to the heater to regulate the heat! As people have found.
This is what the manual says about it:
Integrated temperature sensor
To monitor the control devices system a temperature sensor is integrated into the MultiControl.
Mainly this sensor secures the device from damage but it can also be used to show the actual
temperature on the display. It is adjusted via the service menu. In case an external temperature
sensor is connected, the integrated temperature sensor is overruled.

I dislike the multicontrol intensely.the rubber knob kept falling off of mine and now I have lost the little reset pin.

I have bought the rotary dial but have the socket for the multicontroller with many wires whereas the rotary only has two wires,how do I overcome this please ?

Edit: scrub the question,I have just found an adapter in the box

 

[oldiebut goodie]

There should be a plug on your loom for the rheostat - 4 wires, red, black,blue,white with a label on usually saying 'user interface potentiometer' if you are going to use the rheostat alone.

 

[richi]

There should be a plug on your loom for the rheostat - 4 wires, red, black,blue,white with a label on usually saying 'user interface potentiometer' if you are going to use the rheostat alone.

I have this



And the controller has this socket



And came with this adapter

 

[oldiebut goodie]

Aaaaah.... you have a Unicontrol not a Multicontrol! That was designed as an upgrade to the old 1531 timer hence the grey socket for the old 1531 timer plug.
If you haven't got the red/black/blue/white wires and plug and lead on your loom you will have to make your own up to fit the grey socket. It should be present on the loom as standard though.

What model heater are you running there?

 

[Dieseldonkey]

This is what the manual says about it:
Integrated temperature sensor
To monitor the control devices system a temperature sensor is integrated into the MultiControl.
Mainly this sensor secures the device from damage but it can also be used to show the actual
temperature on the display. It is adjusted via the service menu. In case an external temperature
sensor is connected, the integrated temperature sensor is overruled.

Is there a way we can get access to the service menu @oldiebut goodie? I have an Airtop 2000STC with Thermocall and also an external temperature sensor. I'd quite like to have the multi controller display the actual temperature its detecting from the external temp sensor.

 

[oldiebut goodie]

Not user accessible - you need the diagnostic interface. They aren't cheap - around £450 so that's out. A Webasto dealer should be able to do it in 5 minutes. It isn't something that I have tried to do myself though. I'll take a look at one later to see what's what.

 

[oldiebut goodie]

It appears that the default setting in the Multicontroller is for the temp display to be on anyway - does yours display a temp at present? If so it will just default to the external sensor when connected.

 

[Trudy Danby]

H

What model heater?
Are you sure that you are talking about a thermostat as thermostats have not been used on Webasto heaters for donkey's years. Current models use a rheostat, the heater ecu compares the air temperature entering the heater with the set temperature of the rheostat. The air will always be cooler entering the heater, if mounted at floor level, than that which you feel at mid-height in the vehicle, if you want it to behave more like a thermostat and sense the mid-height temperature you have to fit an external temperature sensor at that height. ( Or set the rheostat at a lower temperature setting than you are currently using ). The heater varies the heat output ( between 0.9Kw and 2Kw on a 2Kw model, 1.5Kw and 3.5Kw on a 3500 and 1.5Kw and 5Kw on a 5Kw one - and so on) as the intake air temperature reaches the setpoint of the rheostat - how do you know when it has reached temperature as you see it?

Hi the heater is a 2000 airtop It is located under the passenger seat. The switch to turn it on and the rheostat is located half way up the van in height and 2/3 of the way back the van. It runs to get up to temp and then the heating element clicks off but the fan keeps running all night. I understood that it would run to cool the heating element down but would then cut out until the van temp drops sufficiently for it to cut back in again. I didn’t think the fan would stay blowing cold air all night?

 

[oldiebut goodie]

There are several different 2000 models - D/S/ST/STC. I am assuming a ST or STC if it is a recent heater. You don't normally have a separate switch for turning it on and off as that is incorporated in a rheostat. It doesn't matter where a rheostat is mounted as there is no temperature sensing in it. Put up a pic of your controller/rheostat/thermostat so that I know what you are actually using. We may well be at cross purposes here.
The heater isn't supposed to switch off the heat when it reaches temperature it is supposed to reduce the heat output as above and increase the heat again as the temperature drops. It doesn't behave like a thermostat and switch the heating off. It will switch the heating off completely if the air temperature at the heater inlet is higher than than the setpoint selected by the rheostat but it should go into total shutdown rather than ventilation mode. ( That said I have had one ST heater that did that whilst being tested but it only did that once which I put down to an error in the software ) It will not restart automatically if it has shutdown it needs to be switched off and restarted. It is better for your batteries to keep it running rather than having the relatively high battery drain of a restart - between 12 and 8Amps whilst the glow pin is operating.
I think that you are expecting it to behave in a different manner to the way it does.

 

[richi]

Aaaaah.... you have a Unicontrol not a Multicontrol! That was designed as an upgrade to the old 1531 timer hence the grey socket for the old 1531 timer plug.
If you haven't got the red/black/blue/white wires and plug and lead on your loom you will have to make your own up to fit the grey socket. It should be present on the loom as standard though.

What model heater are you running there?

I think it is the 2000stc

 

[oldiebut goodie]

The STC loom should have the plug - look further back down the loom in case someone has taped it back.

 

[Dieseldonkey]

It appears that the default setting in the Multicontroller is for the temp display to be on anyway - does yours display a temp at present? If so it will just default to the external sensor when connected.

View attachment 44386

Thanks @oldiebut goodie .
It just displays the temperature that you set it too, as shown in the pictures below. Additionally, am I right in thinking there is no manual control of the fan speed in heating mode with the 2000STC. Seems to be fixed on normal. No option to change it to boost or eco. Although there is 4 fan speed settings in ventilation mode. But this is just circulating ambient air through the van.

 

[oldiebut goodie]

There is no adjustment of the fan in heating mode as it is governed by the heat output - it will drop down to around 2000 rpm from 4500 rpm when at 0.9Kw heating output. There is no boost or eco settings on the 2Kw heaters that is only on the Evo range. If you could drop the fan speed in heating mode without reducing the heat output you are then in the realms of overheating the heater.
Look at this diagnosis report on a ST - there has been no boost running as it isn't possible ( boost is greater than the rated output of the heater for a limited duration only):



This was a 2000STC Petrol model ( again no boost):

Diagnosis report Webasto Thermosystems
------------------------------------------------------------------------------------------


Configuration:
--------------
W-Bus version...............................................................3.1
Device name..............................................................SG1574
W-Bus code.........................................................5A5CF85A3900
Fuel type..............................................................Gasoline
Heating duration limitation...................................................0 [min]
Factor for shortening of ventilation duration...............................1/1
Device identification number..........................................09030897B
Dataset identification number.......................................09030944C03
HW version................................................................23/14
SW version...........................................................25/15 5.76
Date of manufacture control unit.......................................00.00.00
Date of manufacture heater.............................................21.11.17
Customer identification number.................................................
Serial number........................................................1732200050
Test signature.............................................................5347
Minimum voltage threshold..................................................10,5 [V]
Maximum voltage threshold....................................................16 [V]
Delay for supply voltage min. detection......................................20
Delay for supply voltage max. detection.......................................6
Serial number USB adapter.................................................34361

Operating data:
---------------
Working hours..............................................................0:34 [h:m]
Operating hours............................................................1:03 [h:m]
Start count...................................................................4
Burning duration PH 1..33%.................................................0:00 [h:m]
Burning duration PH 34..66%................................................0:16 [h:m]
Burning duration PH 67..100%...............................................0:18 [h:m]
Burning duration PH >100%..................................................0:00 [h:m]
TRS counter...................................................................0
Output temperature.........................................................33,6 [°C]
Set temperature potentiometer.................................................5 [°C]

Error:
------

------------------------------------------------------------------------------------------
12.01.19 22:27:55 Webasto Thermo Test 2.16.1

 

[oldiebut goodie]

Boost and eco on a Evo heater ( Low and Boost):

Diagnosis report Webasto Thermosystems
------------------------------------------------------------------------------------------


Configuration:
--------------
Webasto ident no.....................................................3312440000
Date of manufacture.......................................................13/61 [week/y]
Device name.................................................................ZHE
Fuel type................................................................Diesel
12/24V......................................................................12V
Serial number USB adapter.................................................34361

Operating data:
---------------
Operating time at low power range............................................70 [h]
Operating time at middle power range.........................................31 [h]
Operating time at high power range...........................................60 [h]
Operating time at boost power range...........................................2 [h]
Glow plug cycles............................................................310

Error:
------
Fault 1..............................................Metering pump interruption
Code....................................................................07/02
State of fault.............................................not stored, actual
Operating hour counter......................................................0 [h]
Fault 2................................................................No start
Code....................................................................01/00
State of fault.........................................not stored, not actual
Operating hour counter......................................................0 [h]
Fault 3..................................Flame was detected prior to combustion
Code....................................................................04/00
State of fault.........................................not stored, not actual
Operating hour counter......................................................0 [h]
Fault 4............................................Setpoint transmitter invalid
Code....................................................................0C/02
State of fault.........................................not stored, not actual
Operating hour counter......................................................0 [h]
Fault 5.................................................Heating unit overheated
Code....................................................................0A/00
State of fault.........................................not stored, not actual
Operating hour counter.....................................................80 [h]

------------------------------------------------------------------------------------------
27.11.18 16:39:40 Webasto Thermo Test 2.16.1

 

[Dieseldonkey]

Thanks @oldiebut goodie . What your saying about the fan speed in heating mode does make sense, now I think about. Better to let it self govern the RPM of the fan to match its heat output from the burner. It would just be nice to have the fan running slower at night to reduce the noise a little, without having to drop the temperature setting, in order to get it to run slower.

 

[KenD]

I have a quick question, not sure if it should be a new thread, but here goes.
I have a Webasto Airtop 2000ST fitted to a 2012 van I bought, but the cable loom is chopped off so don't know if it works.
I have removed it from the van and am disassembling it (like you do) and discovered the overheat sensor is open circuit.
Any ideas what resistance it should be. It looks like the one in the picture attached.
I need to know how many new bits I need to get it going before I buy a temp controller.
Cheers

 

[oldiebut goodie]

Page 22 of the workshop manual.