Not sure if my working title will still seem like a good idea in the morning,
but it's a fun pun. :-)

Some heater project progress to report:

*******

Now Mounted, and Completely Exhausted


Last month I reported that we were testing Webasto's new "self install" kit by
putting a new heater aboard "Indulgence."

The process continues, without undue drama. It was my hope to have
substantially more of the project completed by press deadline, but it has been
a busy month in the magazine business and I have accomplished only two
additional, but important steps. The Air Top 5000 has been mounted, and the
exhaust system installed. The specific plans have been made for installing the
fuel pump and the cold air return lines, the next two steps.

The instruction book and the assorted parts and fittings packed in the Blue
Heat box have allowed the installation to go forward with a minimum of
guesswork and error. The most important thing I unpacked from that box, so far,
has been confidence. Gathering all the bits and pieces required in addition to
the heater itself would have been very time consuming, especially for a novice
furnace installer without a list for reference. We are retrofitting the Webasto
Air Top 5000, rather than starting from scratch. While there will be some minor
issues with an existing section of cold air return, Webasto seems, so far, to
have done a credible job of anticipating the needs of most installations.

The new "Webasto" aboard "Indulgence" will mount athwartship, allowing a
straight run of several feet in the warm air duct before branching to outlets
fore and aft. Webasto includes a sturdy, L-shaped metal mounting bracket that
would allow the Air Top 5000 to be affixed to a bulkhead. The installation book
said that it would be permissible to turn the heater 90-degrees either
direction from "right side up" if mounted horizontally. The only position that
must be avoided would be an installation where the furnace was turned so that
the exhaust gas exited through the resulting "top".

For several reasons, a bulkhead mounting would be less than optimal on
"Indulgence." We elected to hang the bracket from the engine room headliner.
This position would leave a vertical, rather than horizontal, mounting surface
available. The engine room is below the salon, and there is a "dead space"
above the engine room headliner equal to the thickness of the framing under the
teak and holly sole in the main cabin. The headliner stock is 3/8 plywood,
covered by a thin layer of foam sound insulation under plastic facing. The
mounting bracket would need to be attached with fasteners that screwed into the
overhead plywood, rather than bolted through, as there is would be no access
into the dead space without tearing up the cabin sole. The Air Top 5000 isn't
very heavy, but even so I was concerned about the lack of "bite" the fasteners
would get in 3/8 stock.

We selected a piece of ½- inch exterior plywood from the scrap bin of a local
lumberyard. It was too small to sell for most purposes, but at about 15 x
18-inches it was just perfect for sistering to the engine room overhead. It was
also available at the right price, free. We secured the reinforcement piece to
the engine room overhead with a series of screws, and then mounted the L-shaped
bracket with six lag screws turned through our adequately beefy 7/8-inch of
combined plywood. I tested the mounting bracket by lying on my back and doing
an upper body "pull-up". It was completely solid, more than substantial enough
to support that small fraction of my weight represented by the Air Top 5000.

Securing the Air Top 5000 to the bracket was simple and straightforward. A
rubber pad was supplied to slip over the combustion air intake and exhaust
ports, as well as the fuel intake fitting on what was gong to become the aft
side of the heater in our installation.
The furnace, with rubber pad in place, bolted up effortlessly to the precut
holes in the bracket. Once the bracket itself was installed, hanging the heater
was literally a matter of only several minutes' time.

Plans for the exhaust through hull fitting had to be revised from an earlier
conclusion.
Our old furnace had a larger diameter exhaust hose than the new, and a new
through hull would be required. It seemed initially appealing to use the old
exhaust through hull as combustion air intake fitting, but a careful reading of
the instruction manual indicated that would not be feasible in our application.
Webasto requires an 18-inch separation between the exhaust through hull and the
combustion air intake through hull. Installing a new exhaust fitting 18-inches
aft of the old one would put the connection behind the port fuel tank- an
unworkable location. Moving the exhaust fitting 18-inches forward would put it
in a position closer to our normal bow wake than I would prefer. I removed the
old through hull, discovered enough "meat" around the edges to allow a secure
mount for the new through hull, (held in place with three stainless bolts
through a face plate and backing plate) and marked the bolt hole locations on
the exterior of the hull.

With three mounting holes drilled, I set the through hull and external gasket
in place, criss-crossed it about six times with masking tape, and hurried into
the engine room to secure the interior gasket, backing plate, nuts and washers
before any unfortunate or expensive splashing could occur. I felt much better
after the first nut was partially threaded on the first bolt- the fitting would
not fall out, even if the high tech masking tape ripped loose outside. The
stainless Webasto fitting terminates in a 90-degree angle on the outside of the
hull. I angled the terminal fitting down and slightly aft to reduce any
tendency to collect bow spray as well as to create a "low pressure" zone
immediately beyond the exhaust fitting when the vessel is underway.

According to the instructions, there are a few factors to consider when
designing an exhaust line. The exhaust should be as short as possible: not a
problem on "Indulgence" where the heater was only about three feet from the
through hull. The exhaust hose should be routed upward from the through hull to
help guard against seawater splashing past the through hull and finding its way
to the heater. After cresting the upward curve, the hose should be routed below
the heater to create a "trap" between the furnace and the through hull. Webasto
furnishes a union to be installed at the low point of the trap, with a copper
coil to drain away any condensation or seawater that might accumulate in the
line.

Webasto included about 12-feet of flexible exhaust hose, appropriate clamps,
and a rubber-backed fiberglass insulation sleeve to eliminate the risk of a hot
exhaust line setting something afire. The exhaust line cut easily with a
hacksaw. We cut the insulating sleeve long enough to stretch over the clamps
after the assembly was tightened in place, and found the sleeve flexible enough
to stretch over all the hardware and fittings.

With the trap drain and exhaust line installed, we noticed the upward curve
near the through hull was only a few inches removed from a rubber fill hose for
the port diesel tank. We flexed the exhaust system enough to create about a
six-inch gap between the insulated exhaust hose and the fuel fill hose. That
might have been unnecessary, but better safe than sorry. We affixed the top of
the inboard curve to the headliner with a rubber-lined clamp supplied by
Webasto.

Total actual installation time to date, including the removal of the old
heater, about six hours. Another few hours have been spent studying, planning
and revising, problem solving, and running down unforeseeable job specific
items such as our bit of plywood.
My guess is that the job is about 25% accomplished, and I hope to be able to
report substantially more progress before our next issue.