Webasto heater operation???

[dog]

Hello all, I am hoping to draw on the collective knowledge of any heater experts. I have just finished installing a Webasto Airtop 3500, and am not quite sure what to expect from its operation. On initial start up, the heater runs to full speed and then settles down to any heat setting over 1/2. If I turn the control down below 1/2 heat, the pump ceases to operate and the heater gradually cools down to blow just cool air. I then have to put the control back up to nearly full before the unit will re-fire again. I was of the impression that it was supposed to be infinately variable from the ON position right up to full heat. (The heater is fully bled and shows no fault codes)

Do any of you experience this, or am I just trying to run the heater in hotter ambient temperatures than it will cope with (given that it is unseasonally warm)

Im sorry for the long post, but would be very grateful of some comment/reasurrance.

Thanks in advance

Brian.

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[malcp]

I have a Webasto Airtop 2400s (I think) of 1997 vintage. This has 2 speeds, full power and half power. When the thermostat setting is above ambient temperature full power is used, and when below half power. There is no other setting apart from off. It is possible to have just the fan blowing cold air without heat, but this requires a different on/off switch position and is not part of the automatic operation.

I do not believe the output (of my vintage heater at least) is intended to have a continuously variable heat output power, so it is quiet possible that once the boat is upto temperature even half power is too much. I'm afraid its either turn it off or open a hatch!

Hope this helps

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[Trevethan]

i have an older webasto with a thermostat, which is indeed infinitely varialbe, though it sort of notches into about 4 positions.

Thing ios its the thermostat that is variable, not the temperature of the output so it has to cycle to maintain a particular temperature,



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[Talbot]

This is the area where the webasto is not as good as the eberspacher. Both are infinitely variable as far as temperature, but the Eber has more fan speeds. IIRC it has 4 against the webs 2. It is because of this feature that average power consumption of the eber is lower than the web. However, both of them are more than capable of melting the ice inside the boat. This winter I will actually be able to get warm while working on the money-pit /forums/images/icons/smile.gif

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[pandroid]

I've got a 1999 Airtop 3500 and it does exactly the same

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[dog]

So does that mean that you cant just set the control to low heat and leave it alone?

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[willothewisp]

I've got one going back to 1978, with a Honeywell thermostat which I don't use, and a full power/ 1/2 power switch. After running the unit for about 10 min. full blast, I set the switch to 1/2. Sometimes it shuts itself off after a time, to start working again after a time, so I guess the thermostat is still somehow doing its job. Meanwhile it doesn't blow any cold air, however. That's a different pos. of the starter switch. Before shutting the unit down I run it at full blast again for some 10 min. Makes it easier to start next time.

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[malcp]

Yes you can set the thermostat to low and leave it alone. However as the heater cannot output less than the half power setting you could well find the boat getting hotter no matter how much further you turn the thermostat down. The only option after this is to switch it off or open a hatch. If you switch it off make sure you allow it to run it's cooldown cycle (full fan with no heat) which lasts for 2 - 3 minutes before it shuts off completely (automatically). The thermostat maybe continously variable but the heater output is not. Full power, half power and off.

This, of course, assumes your (newer?) model works the same as my Airtop 2400s.

Actually, dog, re-reading your post it may be your Airtop does include 0 output heat as part of the automated operation. Check the manual for this. Assuming you had not raised the boat temperature to "oven heat" perhaps it is the thermostat which needs checking.

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by malcp on 21/11/2003 10:51 (server time).</FONT></P>