Automotive Air Conditioning Information Forum

The Trans Air tech guy recommended running high and low pressure switches. But when I look at pressure switches, I find many binary types that are supposed to protect the system for over or under some pre-set pressure.??? Can you depend on these single switches or should I go back to two separate switches as was originally installed. It's a bus type motorhome system.

I would suggest individual switches for each setting. Ability to place the switch in the needed area is why I suggest 2 switches.

Where are the two needed areas? I have two bungs, both on the high pressure line. One back by the pump and one up front by the condensor/evap line. It's a diesel pusher.

If your system has an accumulator I would use the LPCO for the low side (if the port is available) and a high side binary in the discharge line. Otherwise, I see no need to place 2 binaries in the same line. They do nothing but shut the system down when pressures reach an improper level.

I don't have an accumulator in the system. So where does that leave me? The binary I have by the pump high side shuts off under 30 psi and over 406 psi. The forward bung is disconnected as of yet.

Just use a single binary then. No need to have the same switch a few feet apart.

You stated this was a bus. How many evaps and what is the method for cycleing the compressor?

You can place the LPCO in series with the HPCO when installed in the High side of the loop.

This will inhibit compressor operation below about 25f ambient, and when the system is completely empty - static pressure below 30 psi.

A little protection from the worst events.

bohica2xo wrote:You can place the LPCO in series with the HPCO when installed in the High side of the loop.

Knowing the thread on the ports would help also. Most binary switches in Santech catalog are low/high in a single switch.

It's not a standard bus but a Wanderlodge motorhome on a short Bluebird bus chassis. It is the only one of it's kind and was produced for the CEO at a cost of 1.2 million since it was custom built at the Bluebird factory in 1995. It is only 26 feet as opposed to all the other Bluebirds at 42 ft. plus.

The a/c system has only one evaporator at the front center under the dash. The system is Trans/Air. I have part numbers for Trans/Air high and low pressure switches but I hate to go to the expense when I already bought a binary switch if there is nothing to gain in protection.
What say you?

Tim wrote:

bohica2xo wrote:You can place the LPCO in series with the HPCO when installed in the High side of the loop.

Knowing the thread on the ports would help also. Most binary switches in Santech catalog are low/high in a single switch.

Aren't ALL binary switches low/high switches by definition?