Webasto Heat - Where to start?

Tim Good

Tim Good

Well-Known Member
Joined
26 Feb 2010
Messages
2,888
Location
Bristol
Visit site
Ok a totally preemptive question here but... I intend to go down to the boat tonight and begin taking the Webasto apart.

It is from a 1996 boat and apparently it once worked. It is located in the cockpit locker and ducted to every cabin via thermostats. All the thermostats work and pump air. The heater however does not. I turn the switch on and it draws current for a few seconds but then just stops.

Before I remove it totally where might I begin in terms of fault finding?
 
A clue as to what type of heater it is will be a good start, your description is confusing with mention of multiple thermostats so I'm unclear even if it is a wet with matrix or a blown air system. If you get the model number or even a description I can let you have a fault finding chart and/or help you further. But start by checking the voltage at the heater whilst it is trying to start. Does it get to the stage where the pump ticks? it seems at least the glow pin is trying to draw current, assuming the draw you mentioned is 10a +
 
Last edited:
sailorman said:
have you tried replacing the gloplug
check the mikuni site for a fault finding schedule it will give you somewhere to start
Click to expand...

Would it were that simple, but this is not a Mikuni, unless it's one of the early Webasto HL series (unlikely in 1996) it's a full strip to replace a plug, the Mikuni flow chart will be of little help. Hopefully its an AT series with self diagnostic codes, but we'll see.
 
Last edited:
there are Chinese copy spare parts out there so make sure you get genuine bits. I have recently had lots of problems due to a Chinese copy glow pin.
 
First step is to check that it is getting enough power. Check EVERY electrical connection from the battery to the unit.

They take a basin full of amps to get going so any faulty connection will scupper that.

Try starting it with the engine running to get the volts/amps up bit and see if that works.
 
northcave said:
Ok a totally preemptive question here but... I intend to go down to the boat tonight and begin taking the Webasto apart.

It is from a 1996 boat and apparently it once worked. It is located in the cockpit locker and ducted to every cabin via thermostats. All the thermostats work and pump air. The heater however does not. I turn the switch on and it draws current for a few seconds but then just stops.

Before I remove it totally where might I begin in terms of fault finding?
Click to expand...
Check voltage at the heater when you attempt to start. If it drops below 11.5v ?? then it wont start
S
 
skipper_stu said:
Check voltage at the heater when you attempt to start. If it drops below 11.5v ?? then it wont start
S
Click to expand...

Depends not only on the model of heater but whether is is a true marine version, starting voltage can be as low as 10.5v, or almost a flat battery on some and as high as 11.8v on non marine versions. Even then that assumes a heater in good condition, any carbon masking can radically alter that and even take it to a level where you need the engine running or even where that will not cope.
 
My pal had a webasto airtop that would run for a while then stop. In the absence of a multimeter i tried running it with the engine going - it ran ok! I concluded it was a poor battery whose voltage dropped rapidly. These things are very tempimental if the batteries not tip top.
 
ghostlymoron said:
My pal had a webasto airtop that would run for a while then stop. In the absence of a multimeter i tried running it with the engine going - it ran ok! I concluded it was a poor battery whose voltage dropped rapidly. These things are very tempimental if the batteries not tip top.
Click to expand...

Not temperamental, just neglected and abused in too many cases, as I said earlier they will start and run down to quite low voltages if they are looked after, but if not serviced and installed properly they will not.

I liken this myth to another common one, that engines get addicted to Eazystart, they don't, it's just that the fault requiring Eazystart is not fixed, if it were the stuff would not be needed. Same with heaters that require high voltages to start & run, the fault needs fixing, then the extra current will not be needed.
 
My Webasto dates from 2000 and faults show up as errors by flashing lights on the control, which might indicate low voltage or fan failure etc.
 
There seem to be fewer faults reported with Webbies than ebers and almost none with Mikkies but perhaps that reflects the numbers in use.
Just an observation.
 
ghostlymoron said:
There seem to be fewer faults reported with Webbies than ebers and almost none with Mikkies but perhaps that reflects the numbers in use.
Just an observation.
Click to expand...

Numbers do certainly come into it and none of them are intrinsically more or less reliable, well not significantly anyway. It also has a lot to do with the past availability of cheap used ex vehicle Ebers which were often poorly installed and hardly ever maintained.
 
Don't know what model your heater is but our 1994 Webasto started becoming very temperamental. It would run on fan only but not heat. Turned out to be corrosion on the switch contacts and nothing more. An easy check.
 
You must log in or register to reply here.

Share this page

Top