To the collective...
So, I am bewildered as to why FT did not use a low side switch on their Dash AC systems. My coach ( a 2002 U320) as well as others I have seen appear to have the switch deliberately not used (switch installed but terminals capped). My coach drawings show the switch but not wired.
I know enough about refrigeration to understand the need for LP compressor cut out and would like to know FT's thinking and what they hoped to achieve. I know the numbers, and realize the expansive line sets and other oddities associated with motor homes can result in lower than typical low side pressures, but there are appropriate LP switches that would allow for appropriate compressor cycling based on the system load ...
Any enlightenment would be appreciated...
Bob....
The low pressure switch on my '99 is behind the condenser grill at the dryer filter.
That's where mine is on my 2003
Keith
Wow! I gotta look for mine now.
Mine is on my dryer.
It's not an issue of where it's at...it's on the low side line at the compressor, where it should be.
The issue is why FT opted not to use it and just cap the connector on it? Funny thing is it is shown on. The FT dash A C wiring drawing.... Shown just out there in "space" not connected.
There is a reason low side switches are installed....to protect the compressor from a low/no refrigerant flow condition. To some extent the compressor depends upon the cold, expanded refrigerant to help cool the compressor. It can cycle the compressor under periods of extreme cooling loads allowing the system to catch up and not freeze the evaporator. It's also an indicator of restrictions or other potentially detrimental conditions.
So the question still remains, why did FT nope to not implement this standard safety feature? This adds to my list of "what were they thinking" as I encountered many of those thoughts during my recent house DC system lithium upgrade..
Thanks!
"Bewildered Bob"...
Mine is installed and hooked up. I'll check my print later if i get time. I have found several receiver dyers corroded internally and although I dont understand how reccomend changing them anytime the system is opened. Being corroded causes large pressure splits with the expansion valve being restricted. Ive been using R/Ds with an external desiccant indicator.
Parker 3520-016 Receiver dryer (https://www.foreforums.com/index.php?topic=42919.0)
Wonder if it came from the factory that way, OR if someone in the last 22 years has "re engineered" it.
Agree, there should be a low pressure switch to protect the compressor.