Throughly Frustrated with a Webasto Evo 8

[Alpina FG]

I am building a custom camper. It is mounted on a Fuso FG chassis and has a separate heated mechanical room encompassing an AC unit, all electrical and solar controls (1200Watts), lithium batteries, 100 gallons of water, 2 bikes and a kayak. I decided on a Webasto Evo 8 furnace and water heater.

When it works, it is superb. It holds temperature accurately based on a simple thermometer as a check. It's quiet and runs constantly-I do not turn it on and off here in Chicago...so the truck is at a constant 60 degrees.

I installed it in early December. It ran for awhile and coded #13 (overheat condition) based on an internal sensor. After replacing the sensor which requires a complete dismount and disassembly of the unit, it worked perfectly for about 5 weeks. Then it coded a few times for an ignition interruption problem (#2). Yes, it has fuel.

Once restarted it coded the #13 again for the heat sensor.

I'm throughly frustrated at the instability of the unit. Before we can finished the living space, we want to make sure all mechanical systems are working and well tested. I've contacted the vendor (Heatso) and await their response.

At this point I'd put in a different system. Stability is everything.

Suggestions are more than welcome. Any US based vendors or system suggestions ?

 

[dreadlocks]

Might check out Eberspaecher's offerings..

Looking at your heater, I see it comes with intake and exhaust mufflers/silencers.. you try taking those off? Perhaps the install is not getting enough air across on the combustion side of the heat exchanger and thats why it keeps faulting out and wrecking your temp sensors.. I had somewhat similar issue w/another furnace, was faulting out at altitude w/exhaust muffler.. took it off and it went away.. apparently it was just enough to reduce the airflow and I was getting similar shutdowns.

 

[DiploStrat]

If it is on constantly, you probably need to do a 30 minute full power burn. That may well solve you problems, as soot can cause either of those faults.

Check the manual, you need a 30 minute burn every month. Running kerosene can help as well.

I would contact Webasto USA directly: http://www.techwebasto.com/

(N.B. I run mine all winter as well.)

 

[Martyn]

I have experienced similar issues with heater units the common problem to most of them was that the enclosure they were installed in did not have enough ventilation.Once more ventilation was added the issues went away. The last one was resolved by adding a ventilation grill allowing better circulation of cabin air to the enclosure where the furnace was housed.

 

[Alpina FG]

Thanks for the replies. I turned it on this morning (4 degrees F) and it is working perfectly heating then slowing down to a maintenance level. I then opened the door and rapidly cooled the interior and it came right back and successfully reheated the space. Great...but why ?
The furnace is installed in a dedicated mechanical space that is 80 cubic feet, so it has to be large enough. It has return air from the living space equal to what the unit requires and supply (heated) air exceeds the requirement.

I have not tried disconnecting the intake silencer or muffler. I'm willing to, but since it is working again...

The manual does suggest a 15 minute BURN but does not describe how. I suppose you would cool the interior and set a high temperature to cause the "burn".

Thanks again

 

[DiploStrat]

...
The manual does suggest a 15 minute BURN but does not describe how. I suppose you would cool the interior and set a high temperature to cause the "burn".
...

Dead easy - set to air heat only (hot water setting will not work) and set the thermostat to the maximum. Leave for 15 - 30 minutes.

Then reset the thermostat to your desired setting.

A good cleaning burn seems to cure all manner of ills.

 

[Toyaddict]

From my experience in HVAC I would be looking very closely at your install. Not saying your install is at fault. But making sure the return/supply and intake/exhaust are by the book as well as maintaining correct clearances around unit. Making sure hot air isn't cycling back into the return is another place to check. Generally an overheat condition is quite repeatable so your situation is perplexing.

There is a specification on pressure drop across the unit as well, that would be a good way to rule out any restrictions etc.

 

[john61ct]

Many say Espar is more reliable than Webasto.

And the Planar are Russian (knockoffs?) which get a lot of hard usage.

Best to become an expert yourself rather than rely on decent shops around in the US.

Then can get into the $200 Chinese ones

 

[Alpina FG]

From my experience in HVAC I would be looking very closely at your install. Not saying your install is at fault. But making sure the return/supply and intake/exhaust are by the book as well as maintaining correct clearances around unit. Making sure hot air isn't cycling back into the return is another place to check. Generally an overheat condition is quite repeatable so your situation is perplexing.

There is a specification on pressure drop across the unit as well, that would be a good way to rule out any restrictions etc.

The unit has a 3" return so I repeated that and does not recycle and I have 20% more supply numbering 6 than the cross-section of the two supplies out of the unit. I was concerned about pressure as well. The install could be at fault but the exhaust and intake are "by the book" as I read it. There are no clearance issues. It ran for about 4 hours today and then coded to 13 again which is the temp sensor. I pulled the three breakers to reset everything and it has now restarted and is in its second cycle where it heats normally and then I do a cooling (exterior door open) to see if it comes back up...which it did and is running normally now.

Maybe I'll install a second Espar unit as a back up . Or not.

 

[Alpina FG]

I did try a stress test. Cooled the interior to 50 and set the Temp at 90. It reached 70 and failed with the #13 Temp. Sensor code. Now trying to restart.