Parliament/webasto support

Contrary to the instructions in my Marathon owners manual, Marathon Service and Engineering advised me that their 2006 coaches required the webasto unit to be operational to use either 12v coach heat or heat the Hot Water tanks when traveling - a capability my previous 2 Marathons had. After my Marathon warranty expired, I contacted Parliament's service dept.(Rick May) who assured me it would not be a problem to address my request. By adding several valves and related water lines, my 2006 coach now functions like my previous coaches and works like the Marathon owners manual reads. Work was accomplished in a day. This change eliminated the need to burn extra fuel to provide heat and hot water while traveling.Parliament has excellant service personnel who are very familiar with Marathon coaches.

I may be missing something here, but if you run the webasto while you're driving, if the coolant is up to temp (generally is more than up via the engine), then the webasto is not going to use any fuel. It will circulate, but not fire up?

Ray

Ray, that is what Marathon changed on the 2006. The burner had to run no matter what the temperature of the engine coolant was. Parliament reconfigured the plumbing and system logic to function as you described.

The burner will not fire or burn any fuel if the coolant is above the temperature set point of around 160 degrees.

The circulating pump may continue to run however, depending on how the system is configured.

If the burner were to run continuously it would result in an over temperature condition because while the radiator is attempting to cool the engine coolant the Webasto is attempting to heat it up.

Kinda like burning the candle at both ends and expecting to keep your fingers cool.

JIM

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Ray, that is what Marathon changed on the 2006. The burner had to run no matter what the temperature of the engine coolant was.

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Wow, that is very strange. I can't even begin to think of a reason that they would want it to work that way.

ray

So Ross you are saying that the water heaters are not plumbed into the engine coolant system, but a stand alone circuit?
GregM

Gregg, you are correct the webasto was not plumbed into the engine coolant system. Marathon stopped plumbing the Webasto into the engine coolant system because they felt the higher engine coolant (approx. 5-7 degrees) sytem associated with the newer emissions would overheat the coaches hot water tanks. Other converters continued to plumb the webasto into the engine coolant system. Hence, I had parliament add the required isolation valves and associated wiring (which was in my prior Marathon coaches) to enable the system to function as John described.