How to turn on the Westabo heater to preheat engine.

[solardude]

Hello everyone! Hopefully this is a really simple question with a simple switch I have over looked.

As Winter approaches, I am getting ready to rebuild the Westabo heater, I hope it is salvageable.

However, as the unit has wires dangling from the control box in the engine bay, I'm unable to just play with the heater switches inside the coach, so I can't figure out how exactly to turn on the preheat.

On other coaches I noticed rocker switch marked "engine heat" there is no such switch in my bus.

The question is: How do I turn on the engine pre-heat on a 1993 MCI 102C3?

As always, thanks in advance for any useful info on this subject.

SolarDude

[eagle19952]

most have an atypical timer/prover sequence controller some where... it is not as simple as flipping a toggle switch.

you may already know this ?

there are ops and maintenance manuals for most models on line, hope that helps.

[luvrbus]

I found my timer in the compartment under the driver window on a DL3,I have seen them on other buses in the engine compartment.

I plan on trying to remove my Webasto and it is going to be a real pain where MCI mounted it.

My heating system is diesel fired with pre heat so I don't see the need for 2 diesel fired heaters

[Oonrahnjay]

    I have no experience with Webasto heaters other than studying installation manuals for a possible system for my bus but most of the designs I've seen have valving or manifold assemblies that distribute the heat output of the Webasto to the engine preheat, interior bus space heating, a heat exchanger for domestic hot water, etc.  Besides getting the Webasto unit to run, you may need to set valving to link the output from the Webasto the engine. 

[luvrbus]

The valving on a Webasto is done mostly with pumps I don't have any valves no where just aquastats and pumps

[David Anderson]

Not sure what the 4 wires are, but if you don't have a heat exchanger adjacent your engine to circulate engine coolant with Webasto heated coolant you can't heat your engine.

I have a 40k btu heat exchanger that I looped to my engine that scavenges heat from the webasto coolant to preheat the engine.  When driving down the road the webasto coolant scavenges heat from the engine to heat the coach. 

This feature is an add on to the webasto system.  When I purchased it I ordered that way.  It gave me the toggle switch pad you referred to.  You could add this feature to yours, but it will require plumbing and switching upgrades.

David

[solardude]

I FOUND THE TIMER!

A little silly now that I figured it out, I have always wondered WHAT that strange looking clock was just below the dash! Its the heater timer!

So again thanks to everyone, especially those who mentioned "timer" in the post.

Good news is I temporally repaired the wires, and the heater came to life once again! It only fires for about 30 seconds then shuts down, so there is still a problem, but with a little more tinkering and probably cleaning and maybe a few new parts the heater should be fully functional again.

David, the heater is tied into the main coolant line with a circulation pump. Presumably the heater can be used to heat the cabin if I plumb in some heat exchangers off of the old heater core lines.


Thanks again EVERYONE!

[luvrbus]

I am sure his is standard MCI Webasto or Espar setup they didn't use a heat exchanger the units used the engine coolant.

The one I am removing feeds to pump from the bottom of the engine then goes to the top of the engine from the unit then has a aqua stat and toggle switch on the dash to power a pump to heat the interior with existing bus heat a real simple installation.

My house heating system is tied to engine with a exchanger ,I don't need 2 systems with a 1/2 dozen pumps and relays to worry with so I am removing the factory install.

I am going to have some exchangers for sale John wasn't going to get cold this bus it has a lot of exchangers like 5 in the living room,4 in the bedroom and others though out the bus   

[Boomer]

If it fires and shuts down in a few seconds the pump must not be coming on, making it overtemp, although it should never fire with the pump off.  Contact Sure Marine in Seattle for technical assistance.  HTH