Duo Therm AC?

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Alan Glen - 18 May 2005 21:16 GMT

My old A/C unit is a '91 model Duo Therm
13,500 BTU's. The problem with it is
the on/off switch when switched to off will
jump to on for a few seconds or less then
back to off again. I leave the unit in the on
position mostly (no problem) though I am worried to turn the unit
off and leave the trailer for it's possible erratic
on/off switch. If I turn it off and leave I will
turn the breaker off at the fuse panel.
I have the old style thermostat about 2 1/2"
x 5 1/2" not the new digital setup. Has anyone else had similar
problems. The old thermostat
is unavailable though I think I might can locate
one. They want $300-$400 for the new digital
setup. The a/c unit still cools fine...I would
hate to replace the unit over a simple on/off
switch.

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Tom J - 18 May 2005 23:03 GMT

> My old A/C unit is a '91 model Duo Therm
> 13,500 BTU's. The problem with it is
[quoted text clipped - 13 lines]
> hate to replace the unit over a simple on/off
> switch.

There has to be room on the face plate somewhere to mount a round 110
volt 20 amp toggle switch. Then just run the hot (black) wire to one
side of the switch and a jumper back to the junction box where you
removed it.

Tom J

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Chris Bryant - 18 May 2005 23:41 GMT

> My old A/C unit is a '91 model Duo Therm 13,500 BTU's. The problem with it
> is
[quoted text clipped - 9 lines]
> for the new digital setup. The a/c unit still cools fine...I would hate to
> replace the unit over a simple on/off switch.

If it *is* just the on/off switch, a bit of electrical contact cleaner
might fix it up, if it is a problem with the board in the upper unit
though, it's a whole different ball game.
While the thermostat isn't available, the upper board is, though it's not
cheap.

While it isn't mentioned (or sanctioned) by Dometic, it is possible to
convert this to the new style analog remote for around $100. It means
removing the board in the upper unit, installing a pigtail to a new box
with the new board, and wiring the thermostat cable (which has plenty of
wires).

It's not really hard, but it does take some fabrication, and a good
understanding of wiring. The good part is that the new
wiring/thermostat/install assembly could be used with a new upper unit.

Signature

Chris Bryant
http://bryantrv.com

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Alan Glen - 18 May 2005 23:54 GMT

Chris, I've heard of the control board in the
upper unit. I've removed my vent cover under
the unit from the inside and all I seen was the
cable(10 wires) that run up inside the A/C. I
couldn't readily see any control panel.
Everything else on the thermostat works just
fine. I'm leary to pay $45 for the remote and
it not work though if I leave the unit powered
on and can turn the unit off with the remote
that would suffice, but if the problem is at the
control panel then I hate to throw money away.

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Chris Bryant - 19 May 2005 00:31 GMT

> Chris, I've heard of the control board in the upper unit. I've removed my
> vent cover under the unit from the inside and all I seen was the cable(10
[quoted text clipped - 3 lines]
> and can turn the unit off with the remote that would suffice, but if the
> problem is at the control panel then I hate to throw money away.

The aftermarket remote that would work with your unit simply installs in
the 120 volt A/C line before the upper unit- as such, it's pretty
foolproof, as far as shutting the unit off.
The conversion I'm talking about would replace the upper circuit board-
which is inside the upper unit, with a box inside the air return.

Let me look- I might be able to figure out which single wire in the ribbon
cable could be cut, adding a simple toggle switch ti turn it on and off,
but I have very little information on this system, as Dometic simply says
"convert to a Comfort Control Center".

Signature

Chris Bryant
http://bryantrv.com

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Alan Glen - 19 May 2005 01:02 GMT

Right convert to the new comfort control center.
Do you know if the upper control panels are the
same with the 13500 and the 15000?

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Alan Glen - 19 May 2005 00:07 GMT

Tom, my first thought was to buy a toggle switch from radio shack , but
after looking
at the thermostat it is an electronic circuit
board and the switch is kind of built right
into the board.
There are two screws for a remote on/off
switch that I might could wire a toggle
switch into. That could work....The remote
is suppose to look like a tv remote control.
Has anyone ever seen one of those before?
It doesn't seem to practical, but if it will turn
my unit off then great! I would hate to
ruin the electronics fiddling with a toggle
hookup just to see if it might work though
that would be the cheapest solution.
I've never seen the remote before...my guess
is that there is a sensor that wires into the two
screws that the remote control activates. Probably the toggle hook up
there wouldn't work.

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Alan Glen - 19 May 2005 00:24 GMT

Eventually I want to change my 13500 BTU
and get a new 15,000 BTU. If I could buy the
digital thermostat and a new control panel
for the upper unit that would interchange
from the old 13500 to the new 15000 without
having to buy another control panel when
I upgrade then I probably will do that,
I got a price today on a control panel today
for the upper unit and they said about $100
for the thermostat and another $100 for the
control panel and another $28 for an adaptor.
These prices were for a new Duo Therm 15000
BTU unit though and they probably will not
interchange. I'll ask a tech at
Duo Therm tommorow to see if they will and if
they don't I might just burn the $100 for a few
more years of service from my old unit until
then. The new digital comfort control thermostats are nice and the new
control
panel cycles the blower fan completely on
and off in the new models while my old
model has the blower fan blowing all the
time.

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