Webasto Digital Controller

[dbsea]

I have an unknown model Webasto heater in my 2016 C-30 CB. Maybe its the 40/55, i am not sure. In any case, it has the manual controller for temperature and fan adjustment:

https://www.jpcdirect.com/wp-content/up ... 00x300.jpg

I would like to have a digital controller, so i can actually set my preferred temperature. Which digital controller would work, and what is involved in connecting it?

 

[SJI Sailor]

Webasto makes a thermostat that I presume would work: https://shop.cummins.com/CSSNAStore...XMYJRsCBA5cP-g4Bz44BJiaLl2pyepbkaApC6EALw_wcB

I would call them and ask and/or find its manual online.

As for installation I think the main issue would be exactly which location you want to keep at a set temperature. I have thermometers in at least 6 places on our C30 and they typically vary by 5-15 degrees across locations. We've simply learned where to set the analog dial for comfort in the galley and stateroom, as needed.

 

[dbsea]

That makes sense, thanks for the link. I will inquire further. Do we know where the thermostat is for the heater / analog controller?

 

[SJI Sailor]

I'm not 100% but pretty sure it is inside the control unit itself, i.e. the box with the temperature knob and fan selector.

 

[dbsea]

That makes sense, and further clarifies why when I took the boat out during sub freezing temps that the cave was always cold, and so was the forward berth, but the galley /salon were always 1000 degrees! Poor placement of the control unit, IMO.

 

[SJI Sailor]

Also the vent with the most output (closest to the unit) is right there in the salon.

Same here: the salon seems to be always at least 10 degrees warmer than stateroom when heat is going (which is OK with me, just needs management or an extra fan for circulation).

 

[dbsea]

Yeah. I'm generally ok with that too except when its 28 degrees outside, and i can see my own breath in the forward stateroom / head. Thankfully we are through that for this season. 🙂

 

[dbsea]

I did get a louvered vent for the main output that allows me to close it and redirect the air as well. That way i can attempt to keep the stateroom a bit warmer on those frigid nights.

 

[OutdoorGrant]

I have an unknown model Webasto heater in my 2016 C-30 CB. Maybe its the 40/55, i am not sure. In any case, it has the manual controller for temperature and fan adjustment:

https://www.jpcdirect.com/wp-content/up ... 00x300.jpg

I would like to have a digital controller, so i can actually set my preferred temperature. Which digital controller would work, and what is involved in connecting it?

Did you ever figure out a controller that would work?

 

[Mastercraft]

I moved my thermostat to berth doorway. Wire was fished thru wall, (relatively easily which surprised me). I have an after market basic digital and works well except it does not have low or medium fan speeds. It is too noisy on high when sleeping. Sure Marine in Seattle sold me thermostat a few years ago. I am going to talk to them soon to see how many big bucks it is going to cost for a real Webasto digital.

 

[dbsea]

Did you ever figure out a controller that would work?

There isn’t one unfortunately! Have to upgrade the furnace which I’m not going to do until it dies. 🙂

 

[Full_O_Fish]

Depending on what additional hardware you have onboard, there is a work around that I've found... Very cost effective if you already have most of the components

Victron cerbo gx has relay outputs which can be controlled remotely through the portal/widgets. These relay outputs can also be programmed fairly easily to trigger via parameters of other connected devices/sensors. In this case a $30 Ruuvi tag sensor in each cabin space gives temperature/humidity monitoring and can be used to automatically trigger the relay turning on the Webasto unit. The cerbo has direct inputs for 4 temperature sensors but they aren't as cheap as Ruuvi tags, only give temperature not pressure or humidity either, and you need to run wiring compared to wireless.

Fan speed control can also be controlled, but it takes a bit more work and logic control to accomplish.

This also lets you set additional parameters such as locking out the system automatically if fuel level is below a threshold.

 

[dbsea]

Depending on what additional hardware you have onboard, there is a work around that I've found... Very cost effective if you already have most of the components

Victron cerbo gx has relay outputs which can be controlled remotely through the portal/widgets. These relay outputs can also be programmed fairly easily to trigger via parameters of other connected devices/sensors. In this case a $30 Ruuvi tag sensor in each cabin space gives temperature/humidity monitoring and can be used to automatically trigger the relay turning on the Webasto unit. The cerbo has direct inputs for 4 temperature sensors but they aren't as cheap as Ruuvi tags, only give temperature not pressure or humidity either, and you need to run wiring compared to wireless.

Fan speed control can also be controlled, but it takes a bit more work and logic control to accomplish.

This also lets you set additional parameters such as locking out the system automatically if fuel level is below a threshold.

This sounds super appealing! My new cerbo from my battery upgrade is very close in proximity to my webasto controller. Can you share a bit more about how you connect the cerbo to the webasto? what kind of wiring harness, any details? Also how to leverage the ruuvi tag sensors? Thank you!

 

[Full_O_Fish]

This sounds super appealing! My new cerbo from my battery upgrade is very close in proximity to my webasto controller. Can you share a bit more about how you connect the cerbo to the webasto? what kind of wiring harness, any details? Also how to leverage the ruuvi tag sensors? Thank you!

In the cerbo unit you need to turn on Bluetooth. Then go into settings, I/O, and enable Bluetooth sensors then select to add each of the sensors when the pop up.

From the relay menu, the easiest way to go is to use relay 2 which has a selectable temperature relay mode. From here you just select your conditions and temp sources and it's basically all set up. (There are some nuances that aren't accomplishable from this route, but it's quick, functional, and easy to implement.

The relay 2 output is capable of switching up to a 6A load, but since there's a fan motor involved the flyback current on the coil could cause issues in short order. The best way to implement this is to wire the common and normally open of relay 2 into the coil of an automotive relay (specifically one that has an internal discharge resistor to combat flyback from motors) that is capable of switching a larger load 15A, 45A, 60A, etc. This relay is then used to switch on/off power to the Webasto unit.

The more complex method would be to use relay 1 which can be configured for auto gen start, which allows you to specify warm up and cool down periods and minimum running, etc. allowing for more specific control to ensure the unit doesn't run for too short a time for it to reach operations temperature and carbon up the burner. This also allows for setting of a lockout/shutdown based on fuel tank level which could be interfaced directly to one of the tank inputs or read from the n2k network which likely already has the tank level reported. If you have the Venus OS large firmware loaded, you could enable node red and from there program even more control such as activation based on humidity from the Ruuvi or code in a PID algorithm so the system can actually "learn" how to control the heater so it will turn off before the desired temp is reached and letting the residual heat flow carry the temp perfectly to the desired level. Also works in reverse to monitor the rate of cooling and turn on the unit early so that it goes through its warm up before the temp drops below the set point.

 

[dbsea]

In the cerbo unit you need to turn on Bluetooth. Then go into settings, I/O, and enable Bluetooth sensors then select to add each of the sensors when the pop up.

From the relay menu, the easiest way to go is to use relay 2 which has a selectable temperature relay mode. From here you just select your conditions and temp sources and it's basically all set up. (There are some nuances that aren't accomplishable from this route, but it's quick, functional, and easy to implement.

The relay 2 output is capable of switching up to a 6A load, but since there's a fan motor involved the flyback current on the coil could cause issues in short order. The best way to implement this is to wire the common and normally open of relay 2 into the coil of an automotive relay (specifically one that has an internal discharge resistor to combat flyback from motors) that is capable of switching a larger load 15A, 45A, 60A, etc. This relay is then used to switch on/off power to the Webasto unit.

The more complex method would be to use relay 1 which can be configured for auto gen start, which allows you to specify warm up and cool down periods and minimum running, etc. allowing for more specific control to ensure the unit doesn't run for too short a time for it to reach operations temperature and carbon up the burner. This also allows for setting of a lockout/shutdown based on fuel tank level which could be interfaced directly to one of the tank inputs or read from the n2k network which likely already has the tank level reported. If you have the Venus OS large firmware loaded, you could enable node red and from there program even more control such as activation based on humidity from the Ruuvi or code in a PID algorithm so the system can actually "learn" how to control the heater so it will turn off before the desired temp is reached and letting the residual heat flow carry the temp perfectly to the desired level. Also works in reverse to monitor the rate of cooling and turn on the unit early so that it goes through its warm up before the temp drops below the set point.

Thanks. So something like this?

https://a.co/d/3PSJwCG

 

[dbsea]

In the cerbo unit you need to turn on Bluetooth. Then go into settings, I/O, and enable Bluetooth sensors then select to add each of the sensors when the pop up.

From the relay menu, the easiest way to go is to use relay 2 which has a selectable temperature relay mode. From here you just select your conditions and temp sources and it's basically all set up. (There are some nuances that aren't accomplishable from this route, but it's quick, functional, and easy to implement.

The relay 2 output is capable of switching up to a 6A load, but since there's a fan motor involved the flyback current on the coil could cause issues in short order. The best way to implement this is to wire the common and normally open of relay 2 into the coil of an automotive relay (specifically one that has an internal discharge resistor to combat flyback from motors) that is capable of switching a larger load 15A, 45A, 60A, etc. This relay is then used to switch on/off power to the Webasto unit.

The more complex method would be to use relay 1 which can be configured for auto gen start, which allows you to specify warm up and cool down periods and minimum running, etc. allowing for more specific control to ensure the unit doesn't run for too short a time for it to reach operations temperature and carbon up the burner. This also allows for setting of a lockout/shutdown based on fuel tank level which could be interfaced directly to one of the tank inputs or read from the n2k network which likely already has the tank level reported. If you have the Venus OS large firmware loaded, you could enable node red and from there program even more control such as activation based on humidity from the Ruuvi or code in a PID algorithm so the system can actually "learn" how to control the heater so it will turn off before the desired temp is reached and letting the residual heat flow carry the temp perfectly to the desired level. Also works in reverse to monitor the rate of cooling and turn on the unit early so that it goes through its warm up before the temp drops below the set point.

How do you wire the automotive relay into the Webasto? I have the airtop evo 3900 (2015 year) and the MC-04 controller which is pretty common.

 

[Full_O_Fish]

Thanks. So something like this?

https://a.co/d/3PSJwCG

That may work, but that relay doesn't specify if it has an internal resistor or not. Generally if it's not in the circuit diagram it's not going to be in it (most on Amazon don't as they are cheap but functional for certain applications).

This is the relay that I use: https://a.co/d/hbJvpJH
They are a compact automotive relay but still handle plenty of current for most applications and standard electrical spade connectors fit directly on them.

 

[Full_O_Fish]

How do you wire the automotive relay into the Webasto? I have the airtop evo 3900 (2015 year) and the MC-04 controller which is pretty common.

I have the smaller airtop2000stc unit which uses a single rotary knob controller, but I reviewed the wiring diagrams between your unit and mine. Looks like it's basically the same except your unit has the additional circuits for adjusting the fan/burner into eco, boost, or just fan vs the standard "comfort" operation. From the diagrams it looks like your unit just needs 12v+ delivered via the relay to the black wire coming from the control panel. (Sounds weird, yes, but that's the way it looks from the diagram. There should be red, black, blue, white in one plug and red, white/red, white, and green in the other. +12v comes from the heater and goes to the controller on the red wire, and into the push button "on" switch, then back out of the controller on the black wire to signal the heater to turn on. The blue and white are the 10K rotary potentiometer circuit that sets the desired cabin temperature.) Before committing and shorting something I would cut the black wire and measure the voltage on the side coming from the control panel, should see 0v with the button in the off state, and 12v in the on state.

Wiring in the relay you still have full control from the existing Webasto controller when the Victron system isn't in command/operation of the unit, however the Victron can only control it with regard to turning it on in comfort mode, then turning it off when the cabin is at the right temperature. Whereas the Webasto controller will actually attempt to slow down the fan and the fuel delivery rate to try and hold temperature once it's reached the set point and turns off only if the minimum output is still greater than the needed heating output to maintain temp.

I find that the difference isn't very noticable operationally unless it's very very cold out and people are going in and out of the cabin somewhat frequently. But it's worth it to be able to pre-heat the boat before heading down to it, or set it to do any number of other IOT operations.