Webasto 3500 Heater Problem

[Stork_III]

New boat (to me) has a Webasto 3500 Airtop heater with simple rotary control. Always fires up and runs but lowish heat output compared to previous Eberspatcher DC3L, also very quiet unlike Eber.

Initial problem, now cured, after some hours running it would shut down with long flash + 5 short flash fault code. I found the inline filter was seriously blocked. After filter removed now runs continuously but still heat output is low but better.

Is there another filter within the fuel pump, and if so how is it removed. Pump tick rate is about 2/second, is this right at full heat?

Webasto Installation & Maintenance manual (4 Pages) is not good at either. Anybody have a proper manual or exploded diagrams a the various part.

 

[achwilan]

webasto manuals

One of these?
http://www.suremarine.com/manuals/webasto-repair-manuals/

 

[Stork_III]

Thanks for that, certainly much better than the "manual" supplied with the unit.

Still can't see if filter in fuel pump though.

 

[minkysailing]

Try giving Toby Harris a call at Keto...Webasto expert and very helpful. Tel: 01202 690900 or toby@keto.co.uk. Sounds like you may need some thermoducting and the system serviced.

 

[pcatterall]

2 per second sounds about right but there is probably a fuel check described in your 'new' manual?
You say its not as hot as your D3 but how are you measuring this? I am continually testing eberspachers and they dont seem to be running as hot now but then ambient temps are very low, could it just be this. If the system is ducted are you lossing heat effect here. Unit could just benefit from a clean and scrape of the glow plug and screen . Have another screen (£10) available as I rarlely get one out in one piece.
However a dirty unit will usually show some smoke. Thanks Achwilan for the manual link, very useful.
Good luck.

 

[David2452]

There is no filter in the Webaso dosing pump, they use a seperate one.

 

[gjgm]

I have a newish installation of this, and the output is too hot to leave your hand for long by the vent?
Only disapointments are that the control thermostat is pretty basic, and the system re-circulates, rather than switches off- fine as long as you are not now recirculating cold air....And because of that, use really means, full blast til its toasty, and then switch it off.
But its damn hot...

 

[pcatterall]

My crude test when heater has warmed up is hand 20cm in front of outlet should have to removed within about 6 seconds!!

 

[Stork_III]

There is no filter in the Webaso dosing pump, they use a seperate one.

I was told by mechanic in Jones boatyard, that there is a very small tube filter in the inlet side of the dosing pump, and that the end can be unscrewed to gain access, but have not yet ventured that far.

 

[Stork_III]

My crude test when heater has warmed up is hand 20cm in front of outlet should have to removed within about 6 seconds!!

The old Eber was like that, but not on the Webasto, even with the other three outlets shut off. It runs so quietly, with an exhaust silencer, that I am wondering if a fuel restriction ie blocked filter in pump is forcing the fan operation onto a low/medium heating stage? Most of ducting up to saloon area is insulated as well.

 

[snooks]

After filter removed now runs continuously but still heat output is low but better.

What about the air flow? is that good? Could there be a hole in the ducting or could it be crushed? Could something be over or stuck down the air inlet?

If the airflow is alright, and you're going to the boatshow, go to the Webaso stand and speak to Toby @ Keto and someone else mentioned, very knowledgeable, very good, very thorough and busy because of it. He won't be on that number during the boatshow as he's on the Webasto stand