Webasto heater modifications to use as primary heat while parked

[dbsoundman]

Hi all, I haven't yet found a thread where people discuss their ideas (theoretical and actual implementations) for repurposing their Webasto coolant heaters and either the bus heaters or some other heater/blowers to keep warm overnight while parked.


My current plan is as follows:

• For my phase 1 buildout, I'll run a wire to power the blower switches for the bus heaters by the driver's seat to my house batteries rather than the start batteries to save on battery draw overnight. The house batteries will charge off the alternator while driving so I'm not too worried about drawing down the house batteries if the heaters are on going down the road.
• Might also run a switch into the driver's area to manually turn on/off the Webasto instead of using the funky time clock it currently uses in the fuse box

Later down the road of my build, I actually want to set up thermostat(s) to start the Webasto as needed to keep the coolant temp up, and cycle the blowers high/low/off as needed. I wasn't sure if stopping and starting the Webasto was a good idea; not sure if the tradeoff of diesel usage vs wear and tear on the Webasto was worth it. I'd also have to come up with some sort of custom control to do a 2 stage blower control.


So, what did YOU build, or what are you planning to do?

[joeblack5]

My thread elf bus post 93 and on ..larger heater core , dash heater and engine preheat.


In our larger bus floor heating in Dory

[Simplicity]

My limited understanding is the wabasto is meant to simply warm the coolant before starting, and not meant to be run continuously. I know they have similar heaters used specifically for interior heating, but I'm not sure the wabasto will have a very long life as a interior heater.

Per using your front driver heater, I'm not sure it will have the umph to heat the bus effectively. It might make a good backup or supplemental, but I don't think it could push the amount of heat for the bus size.

Sorry, not trying to be negative, and I have no facts to back up my thinking, yet some things for consideration.

Best of luck.

[dbsoundman]

Originally Posted by Simplicity

My limited understanding is the wabasto is meant to simply warm the coolant before starting, and not meant to be run continuously. I know they have similar heaters used specifically for interior heating, but I'm not sure the wabasto will have a very long life as a interior heater.

Per using your front driver heater, I'm not sure it will have the umph to heat the bus effectively. It might make a good backup or supplemental, but I don't think it could push the amount of heat for the bus size.

Sorry, not trying to be negative, and I have no facts to back up my thinking, yet some things for consideration.

Best of luck.

I may need to try to find out what exact model I have to make sure it can withstand longer usage cycles, good point.

I kept all three of my bus floor heaters so I don’t think I’ll have an issue with heating capacity.

[T-Bolt]

I plan on doing something similar but have not devoted much brain space to it yet.

[cadillackid]

Mopst webastos i know of are designed to be run continuously.. around here in winter when its 5 degrees out the diesel engine wont begin to keep the inside of a bus warm at near idle doing a school route.. the webasto heaters are often left on for the route.. they cycle off when the coolant reaches a set temp.. 170f I think is the default on most of them.. so once the bus gets moving it shuts off.. if the bus temp drops down again then it will come back on..



the ones here in the city schools have a timer that the bus driver hits a button and it runs for X minutes.. that way if they forget to shut it off then it goes into a full shutdown after the timer expires.. most use 2 hour cycles..


I use mine for space heating with Bus heaters all the time.. in both busses I do it.. im about to hook that ill-fated VVKB heater up as a garage heater using an extra Jegs heater and expansion tank I have laying around.. using a gas fireplace vent kit to vent it out the side of the garage.. im sure when i get into build-out of my Holiday lights display in the garage that the heater will be on for hours at a time..

[dbsoundman]

Originally Posted by cadillackid

Mopst webastos i know of are designed to be run continuously.. around here in winter when its 5 degrees out the diesel engine wont begin to keep the inside of a bus warm at near idle doing a school route.. the webasto heaters are often left on for the route.. they cycle off when the coolant reaches a set temp.. 170f I think is the default on most of them.. so once the bus gets moving it shuts off.. if the bus temp drops down again then it will come back on..



the ones here in the city schools have a timer that the bus driver hits a button and it runs for X minutes.. that way if they forget to shut it off then it goes into a full shutdown after the timer expires.. most use 2 hour cycles..


I use mine for space heating with Bus heaters all the time.. in both busses I do it.. im about to hook that ill-fated VVKB heater up as a garage heater using an extra Jegs heater and expansion tank I have laying around.. using a gas fireplace vent kit to vent it out the side of the garage.. im sure when i get into build-out of my Holiday lights display in the garage that the heater will be on for hours at a time..

Excellent! I’m running mine now just to check it out and I heard the heater shut off while the pump is still running (I can tell by the sound).

Did you make any changes to run your blowers from house batteries or other power sources? I was thinking of moving the webasto power over to the house side too, don’t want to lose my start batteries if I’m parked for multiple days running the heaters.

[cadillackid]

on my red bus its all on the main as i dont have house batteries (yet)..


on my DEV bus my heater, its pumps (I run 2) and 2 bus heaters are on House batteries.. I ran a large wire (I think #4) from my house batteries up to my bus switch panel and put a bus bar in with circuit breakers just like the factory.. so I can wire anything from my switch panel into that and move it back later if I decide I dont want it on house.. so I have my door / step heater on it and I replaced the crappy underseat rear heater with a nice ductable Jegs unit.



my bus heater valves are electric.. since a carpenter bus is a parallel flow heating system (2 main trunks of water one supply and one return with each heater pulling one of each). I can close one of my main valves and stop coolant flow to the engine but still allow coolant to circulate within the bus heating system.. the single left-open valve is ballast for expansion and contraction of coolant.. if I open that valve then coolant circulates threough the engine and the bus heaters .. using 2 davies-craig pumps ensures i have enough flow.. although the webasto pump and then using the Bus Booster pump can accomplish the same thing.. I just found the bus booster pump uses a ton more amps than my little davies craig pumps..



ive worked in my mobile office all day this way staying nice N warm , connected to the InterWebs and Covid-free



I had a 12kw VVKB heater that seems to be somewhat rubbish.. now im running a 16kw D&E heater that looks similar but works a heck of a lot better.. and my D&E has a digital dial to set my desired coolant temp. 75c is as high as it goes on the dial (though I havent tried sending it a higher number via the computer yet) I cant draw enough heat at 75c coolant to hold the heater on continuous with both fans on high so maybe hotter coolant would be nice.. I do have the option of turning on the key and using the starter batteries if I wish to run an additional fan.. since those batteries are AGM 100AH each i can run a heater fan for a while before id worry the bus wont start.. if I were doing it enough id wire another bus heater to the House side..



my alternator charges my house batteries so when im driving any fans on them are not a draw to the batteries.. there's 4/0 welding wire running the 18 or so foot run from the main batteries back to the house so voltage drop isnt an issue..

[dbsoundman]

Originally Posted by cadillackid

on my red bus its all on the main as i dont have house batteries (yet)..


on my DEV bus my heater, its pumps (I run 2) and 2 bus heaters are on House batteries.. I ran a large wire (I think #4) from my house batteries up to my bus switch panel and put a bus bar in with circuit breakers just like the factory.. so I can wire anything from my switch panel into that and move it back later if I decide I dont want it on house.. so I have my door / step heater on it and I replaced the crappy underseat rear heater with a nice ductable Jegs unit.



my bus heater valves are electric.. since a carpenter bus is a parallel flow heating system (2 main trunks of water one supply and one return with each heater pulling one of each). I can close one of my main valves and stop coolant flow to the engine but still allow coolant to circulate within the bus heating system.. the single left-open valve is ballast for expansion and contraction of coolant.. if I open that valve then coolant circulates threough the engine and the bus heaters .. using 2 davies-craig pumps ensures i have enough flow.. although the webasto pump and then using the Bus Booster pump can accomplish the same thing.. I just found the bus booster pump uses a ton more amps than my little davies craig pumps..



ive worked in my mobile office all day this way staying nice N warm , connected to the InterWebs and Covid-free



I had a 12kw VVKB heater that seems to be somewhat rubbish.. now im running a 16kw D&E heater that looks similar but works a heck of a lot better.. and my D&E has a digital dial to set my desired coolant temp. 75c is as high as it goes on the dial (though I havent tried sending it a higher number via the computer yet) I cant draw enough heat at 75c coolant to hold the heater on continuous with both fans on high so maybe hotter coolant would be nice.. I do have the option of turning on the key and using the starter batteries if I wish to run an additional fan.. since those batteries are AGM 100AH each i can run a heater fan for a while before id worry the bus wont start.. if I were doing it enough id wire another bus heater to the House side..



my alternator charges my house batteries so when im driving any fans on them are not a draw to the batteries.. there's 4/0 welding wire running the 18 or so foot run from the main batteries back to the house so voltage drop isnt an issue..

All great info! I need to pull some panels in my electrical compartment to see my switches better, I had planned to just cut the wires feeding the switches to feed them from my house batteries instead but using a terminal block would be much nicer if I can fit it all in there.


I haven't yet cracked open the panel on the Webasto heater itself yet, but I am curious why it uses 4 wires coming from the front of the bus: in my case they're red, black, white, and green. I remember red connects to the timer in the electrical compartment and I think green is ground, but I'm not sure what the others do yet. Eventually I'll want to know so I can replace that timer with something more useful for me...heck even a regular old on-off switch would be fine since the Webasto will turn on/off on its own as needed.

[cadillackid]

On many of them that’s all the timer does is provide 12 volts to the switch wire.. I just have a switch on my red bus. On when I want it off when I don’t. It will be connected to the remote internet once I get it going in that bus so I can remote control it.

[Simplicity]

Originally Posted by dbsoundman

I haven't yet cracked open the panel on the Webasto heater itself yet, but I am curious why it uses 4 wires coming from the front of the bus: in my case they're red, black, white, and green. I remember red connects to the timer in the electrical compartment and I think green is ground, but I'm not sure what the others do yet.

Here are my thoughts and guesses.
Since the red is coming from the switch, it could be power.
On my bus, we've always found white to be ground.
If red is not power, then black probably is.
If it was AC electrical, I'd agree that green was ground, but in DC I would say it's maybe temperature sensor related?

Is it out of the bus to where you can bench test it?

[dbsoundman]

Originally Posted by Simplicity

Here are my thoughts and guesses.
Since the red is coming from the switch, it could be power.
On my bus, we've always found white to be ground.
If red is not power, then black probably is.
If it was AC electrical, I'd agree that green was ground, but in DC I would say it's maybe temperature sensor related?

Is it out of the bus to where you can bench test it?

I'm pretty sure once I actually open the cover on the Webasto I'll be able to see where the wires land, I just haven't had a chance to do that yet. I also need to "fold out" the outer fuse panel on my electrical compartment so I can see the rest of what's in there, that may also explain some of the wiring. I'm not too worried either way since it seems to be just like cadillac said - red is switched power.

[TJones]

Originally Posted by dbsoundman

I'm pretty sure once I actually open the cover on the Webasto I'll be able to see where the wires land, I just haven't had a chance to do that yet. I also need to "fold out" the outer fuse panel on my electrical compartment so I can see the rest of what's in there, that may also explain some of the wiring. I'm not too worried either way since it seems to be just like cadillac said - red is switched power.

I still need to get my Espar working and figure out how to control it. As far as the wiring from the timer there will be a wire for the on / off signal as well as a diagnostic wire from the computer in the webasto to the timer controller. A 12v thermostat could be used to control a relay(s) that would send 12v to the webasto as well as to turn on an additional water pump and the heater blowers. The webasto will go through a shut down sequence after the 12v signal is turned off. The use of a delayed shut of relay could run the pump and blowers for a time after the thermostat shuts off to get the remaining heat out of the coolant. For the coolant plumbing you would need valves and additional coolant line to bypass the engine from the coolant loop so you aren't heating the engine. You would also need to add an expansion tank in your coolant loop to leave room for when the engine is bypassed.

Ted

[IC08]

Originally Posted by TJones

I still need to get my Espar working and figure out how to control it.

I've got one of those Espar's too, but I pretty much junked the radiators taking them out. Do you plan on repurposing the stock ones or using another?

[DrDanger]

Take a look here:

https://www.skoolie.net/forums/f51/h...t-19412-2.html


I went into a little more detail here:
https://www.skoolie.net/forums/f11/p...tml#post423372


I guess I never finished the story there...after purging air for about an hour with help from my dad, we got all the air out and I started to get heat on my floor. If I had to do it again I would have kept the original rear heater and plumbed it into my floor loop to give a bit of a heating boost to the rear.

[cadillackid]

Originally Posted by DrDanger

Take a look here:

https://www.skoolie.net/forums/f51/h...t-19412-2.html


I went into a little more detail here:
https://www.skoolie.net/forums/f11/p...tml#post423372


I guess I never finished the story there...after purging air for about an hour with help from my dad, we got all the air out and I started to get heat on my floor. If I had to do it again I would have kept the original rear heater and plumbed it into my floor loop to give a bit of a heating boost to the rear.

getting the air out of hydronics and keeping it out is often one of the most difficult things to do.. you can still put in a Jegs /. summit etc aftermarket heater.. assuming your pipe loops are warm enough to support a fan-forced heater.. you need to have realistically minimum 120-140 degree water to feel good warm air from a fan forced heater.. which seems high for a floor loop at least sustained.



the original rear underseat bus heaters are not the best ones to keep generally.. they most times use fans and not blowers.. which make a lot of noise and dont move a lot of air.. the dashboard and step well heaters run much quieter and move more heat.

[TJones]

Originally Posted by IC08

I've got one of those Espar's too, but I pretty much junked the radiators taking them out. Do you plan on repurposing the stock ones or using another?

My rear heaters worked and were in good condition so they will go back in.

Ted

[dbsoundman]

Originally Posted by cadillackid

getting the air out of hydronics and keeping it out is often one of the most difficult things to do.. you can still put in a Jegs /. summit etc aftermarket heater.. assuming your pipe loops are warm enough to support a fan-forced heater.. you need to have realistically minimum 120-140 degree water to feel good warm air from a fan forced heater.. which seems high for a floor loop at least sustained.



the original rear underseat bus heaters are not the best ones to keep generally.. they most times use fans and not blowers.. which make a lot of noise and dont move a lot of air.. the dashboard and step well heaters run much quieter and move more heat.

That is a good point, I kept my drivers heater for now but it’s definitely just a fan behind a radiator basically. Are there good aftermarket “blower” heaters that will work in a bus?

[cadillackid]

Originally Posted by dbsoundman

That is a good point, I kept my drivers heater for now but it’s definitely just a fan behind a radiator basically. Are there good aftermarket “blower” heaters that will work in a bus?

surprised your driver heater is a blade fan.. all but my door heater are squirrel cage blowers..



I like the Jegs heaters.. I use this one in my bus and it flat out rocks.



its ductable, quiet and moves a lot of heat..



https://www.jegs.com/i/JEGS+Performa...YaArwiEALw_wcB


I didnt use the fan control it came with.. I connected it to my own switching..

[dbsoundman]

Originally Posted by cadillackid

surprised your driver heater is a blade fan.. all but my door heater are squirrel cage blowers..



I like the Jegs heaters.. I use this one in my bus and it flat out rocks.



its ductable, quiet and moves a lot of heat..



https://www.jegs.com/i/JEGS+Performa...YaArwiEALw_wcB


I didnt use the fan control it came with.. I connected it to my own switching..

That looks great! Might reconsider trying to build in my bus heaters and swap out for these instead…hmm.