RE: [A/S] A/C Thermostat

["Steve @ S&M Cycles and Accessories" <steve@xxxxxxxxxxxxx>]

<Some home type thermostats are effected by the movement of the RV, causing
the appliance to cycle repeatedly.>


This type would be older (or cheaper) thermostats that rely on a bimetal
coil, which most times have a mercury activated switch attached.  The
bimetal coil expands and contracts at an different rate from one side of the
coil ribbon to the other.  This causes the coil to both grow longer or
shorter, but also to increase or decrease the angle of coil.  This action
causes the mercury "ball" to roll back and forth inside of the glass vial.
When the mercury has moved far enough, to one end or the other, to reach the
two contacts the appliance cycles on.

The mercury switch vial is rather heavy for the coil and will bounce all
over the place just by walking the trailer if the floor is weak or the
trailer isn't set on jack stands.  Even more so if the RV or TT is in
motion.  Most likely to the point of being a severe hazard to the continued
life of the motor, start-up capacitor, and circuit cabling from the
continued heavy start-up phase current draw.

Digital is the only way to go.  Besides, the digital thermostats are more
efficient, programmable, and of course use less juice.  And, if there is the
ability to hardwire the thermostat to 110VAC (the A/C needs it to run) then
one would never be without a cool trailer as long as there is power to run
the A/C.

Steve Jones
'58 Airstream Overlander - Modern Remodel
Original Parts Available