Retrofit a diesel-fired heating system?

[Donald Watson]

The Webasto Thermo 90 is definitely a decent unit. I installed one on the
38' sailboat I lived on for seventeen years. The Thermo 90 was used
continuously for seven or eight years, logging well over 4,500 hrs. It
feeds four radiators, the output of each escapes me at the moment, but each
must be rated well in excess of 5,000 btu.

I have had an issue, however, and that's that the burner appears to burn too
lean. I've had to replace, with new or rebuilt, the burner tubes several
times. I believe that I might have to throttle down the inlet. Webasto
offers some diagnostic software and a 'pigtail' with which to convert to a
serial port feed. I've got to locate this package and remedy the problem,
but I remain an advocate of Webasto products. It's good to know that the
Thermo 90 was sufficient to heat Scott's PT38.

Scott, you could include a thermo switch embedded in a ¾" union to close a
power relay controlling the bus heater motors. Once the coolant temperature
dropped below, say 140 deg. F, the fans would shut down. If you haven't
already done this, another advantage of the temperature contactor would be
to prevent cold air from blowing until the re-circulating coolant was up to
temp.

Donn
76FC33
South Kingstown, RI


From: WanderlodgeForum@yahoogroups.com
[mailto:WanderlodgeForum@yahoogroups.com] On Behalf Of Bill Garamella
Sent: Saturday, December 06, 2008 12:37 PM
To: WanderlodgeForum@yahoogroups.com
Subject: [WanderlodgeForum] Re: Retrofit a diesel-fired heating system?

--- In WanderlodgeForum@yahoogroups.com
, "Scott Forman"
<scottforman75@...>
wrote:
>
> Has anyone ever retrofitted one of the diesel-fired heating systems to
> a mid-80's PT? This one one of only a few features of the newer
> coaches that I really wish I had. It seems to my feeble mind that one
> should be able to install the unit in a bay and tap in to the loop for
> the original hot water heaters coming off the engine, but I am no
> engineer. Any advice on this?
>
> Scott Forman
> 86 PT38
> Memphis
>
Hello Scott,

I recently installed a Webasto Thermo 90 in our 83 FC. We installed it in
the rear driver's
side compartment. I am very happy with the outcome. The plumbing is the easy
part.
Installed it in series with the aux pump loop just before the pump.

Tapped the fuel tank from a spare 3/8 plug that was already equipped with a
standpipe.

The electrical is a bit involved. Installed diodes and power supply for the
aux pump and
winter/summer Sporlan valves with an additional winter summer switch for the
Webasto.
The pump will automatically run when the Webasto is on.

By doing this we did not have to disturb any of the dash wiring /functions.
Therefore,
when the Webasto is off, the hydronic system still functions as it was
designed to with
the engine running.

The Thermo 90 is a varaiable output boiler from 6K to 31K BTU. It is very
efficient.

I have been testing it and it will warm up the coach and block nicely from
20 degrees F
to comfortable room temps within 30 to 40 minuets. Heat starts coming out of
the
coach exchangers within 10 minuets.

The only issue I have not resolved yet has to do with the coach blowers. I
bypassed the
aux bus where they were originally powered and put them on a dedicated 20
amp circuit
at the mid coach sub panel. This is not idiot proof in that once the
thermostat is
satisfied, the blowers will turn off but the blower porwer is still on. If
the Webasto is shut
down, the risk of forgetting to turn off the blower power remains and the
blowers will
run once the temp falls.

I have lots of documentation and photos if you are interested. email
bgaramella@...

NH Bill 83 FC "Casa Billisa"