Wabasto Furnace

[cmillsap]

(07-03-2018 20:05)davidbrady Wrote:  Chuck,

Does this system use the DD S60 coolant as the webasto boiler coolant? I always appreciated the separate boiler fluid and reservoir that the Aquahot provides. This allows heating the coach without also heating the engine, it also makes S60 coolant changes a lot easier and it eliminates a lot of potentially leaky connections in the S60 loop. Does the Wabasto have these features?

David,

Altho the AquaHot units may have some positive features, in my opinion and experience, they require more maintenance than they should, hard to access and repair and the repair parts cost is outrageous.

We very seldom find ourselves in a location where we need to turn on the heaters other than an occasional base board electric heater. However, the weather has been unusually cool (cold) here in Montana. Many overnite temps down in the 30s*F range. So, we've given the Wabasto furnace a pretty good workout over the past month. Supposed to warm up in the next few days tho.

Since I know little about the Wabasto’s internal workings and design and how Marathon adapted it for use on their conversions, most of what I am saying here is conjecture on my part. All I know is that it is a very efficient furnace that works very well. I think these little furnaces were originally designed for use in semi-trucks equipped with sleeper cabs.

Interestingly, I had asked myself the same question about heating using the S60 coolant. So, I did check the temp of the S60 while the Wabasto was running and circulating the coolant. The S60 remained at ambient temp.

The Wabasto furnace manual states that it requires a system large enough to hold at least 5 gallons of coolant. The unit itself has no coolant reservoir and basically exists of a coolant pump and a diesel boiler. The unit is controlled by the SMS thermostat. It appears to me that (on demand) the boiler is lit via the thermostat (coolant pump) and a flow control switch in the coolant line which heats and pumps the coolant through the boiler and through the registers via a closed loop system, but that may be an incorrect or incomplete description of the system. I think it works similar to a common natural gas "on demand" water heater.

There is also a second closed loop system which allows the Wabasto to heat the water in the (2) water heaters. That loop is controlled by a 12V water heater switch located on the DC panel. I have yet to find out how to allow the Wabasto to heat the coolant in the S60. It may not have that ability as plumbed and engine preheat is only by electric cal-rod in the crankcase?