Trinary Wiring

Shaun

Supporter
One more for the pot, so pressured up the AC tonight, clutch works fine (did not on low pressure but did when fully charged). The Blue / White which triggers the fans to run is there a delay on that or will it only trigger when the engine and compressor are running as I am not getting 12V out when the AC is on
I have wired as follows

Black/White - This is a 12v feed from the Ac on / off switch
Red / Blue - Earth
Red / White - Compressor clutch
Blue / White - Fan relay feed

any thoughts? Looking on the web I think my wiring is good just maybe not understanding fully how the trinary work

Cheers
 

Shaun

Supporter
Just for info for any other poor soul who gets his loom from a guy who clearly did not have its heart in the job at the end :)

So the trinary provides a earth contact when the condenser fan is needed to activate the fan relay by providing an earth, except my fan relay is not wired for a earth switch its a live supply switch with a permanent earth.

I sort of found this today as started the engine and presto cold air (great start) but then the fuse blew, I think that's when the trinary called for the fan a short delay after the compressor kicked in, by doing that it shorted the circuit as supplied a nice earth to the +ve supply.

Will test tomorrow, cannot start at night it scares the wildlife as I have to have the shutter door open, my workshop is large but its amazing how soon the CO alarm goes off when I start the beast.

So hopefully tomorrow night I can start body fit!!
 

Howard Jones

Supporter
Is this helpful ?
 

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  • vintage air trinary switch schematic 2.png
    vintage air trinary switch schematic 2.png
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Hi Shaun,
when I did my wiring, this was the hardest part to figure out. However once you fully understand how the trinary switch operates, it becomes a lot clearer. The following I eventually found in a Lotus service manual and expalins why you have delayed reactions

The Trinary switch serves two functions. One portion of the switch cycles the condenser fans once the refrigerant pressure reaches 235 psi (16 bar) and turns off the fans at 190 psi (13 bar).
The other portion of the switch protects the system from damage due to low refrigerant or excessive pressures by turning off the compressor. Power to the compressor is interrupted once the refrigerant pressure drops below 29 psi (2 bar) or exceeds 397 psi (27 bar) at the Trinary switch. The Trinary switch automatically resets once pressures are restored to a safe level.

Switch 1 Condenser Fans:
On 235 psi (16 bar)
Off: 190 psi (13 bar).
Switch 2 Compressor:
Off: drops below 29 psi (2 bar - Low) or exceeds 397 psi (27 bar - High)

Regards,
Andy
 

Shaun

Supporter
Cheers Andy and Howard (Good diagram by the way)
Andy very clear explanation best on the web, my stumbler was the fact my fan setup was not wired as it should be as per Howards diagram, where the relay is controlled by the earth, the chap who did mine wired so it was controlled by a feed. So that makes even more sense now that you say the trinary switches on the fans at a certain pressure as it confused me as to why the engine ran for a bit, then two fuses blew, one for the fans and one for the heater matrix, reason was the trinary closed and earthed the fans and the trinary supply comes form the heater matrix (powers on when the heater matrix fan is turned on) so pop!!!
Worth it though will keep me cool...I hope
 

Shaun

Supporter
Hi Shaun,
when I did my wiring, this was the hardest part to figure out. However once you fully understand how the trinary switch operates, it becomes a lot clearer. The following I eventually found in a Lotus service manual and expalins why you have delayed reactions

The Trinary switch serves two functions. One portion of the switch cycles the condenser fans once the refrigerant pressure reaches 235 psi (16 bar) and turns off the fans at 190 psi (13 bar).
The other portion of the switch protects the system from damage due to low refrigerant or excessive pressures by turning off the compressor. Power to the compressor is interrupted once the refrigerant pressure drops below 29 psi (2 bar) or exceeds 397 psi (27 bar) at the Trinary switch. The Trinary switch automatically resets once pressures are restored to a safe level.

Switch 1 Condenser Fans:
On 235 psi (16 bar)
Off: 190 psi (13 bar).
Switch 2 Compressor:
Off: drops below 29 psi (2 bar - Low) or exceeds 397 psi (27 bar - High)

Regards,
Andy
Hi Andy
Quick question how soon should Switch 1 kick in? I ran it up and got cold air for about 5 minutes but the fans still did not trigger, my charge is about middle green so good pressure, just wondered if I actually have a duff Trinary, most of the ret of the AC kit was a bit of a balls up
Cheers
 
Hi Shaun,
maybe you need to leave it running a bit longer, as the ambient temperature is still low and the system is not working that hard. Trying to bridge the switch to prove the circuit is OK , would be a good test, so would trying another switch
Andy
 

Shaun

Supporter
Hi Shaun,
maybe you need to leave it running a bit longer, as the ambient temperature is still low and the system is not working that hard. Trying to bridge the switch to prove the circuit is OK , would be a good test, so would trying another switch
Andy
Ah ok will do, circuit is fine when bridged so I know its the Trinary not yet doing its bit but will let it get right up to temp, etc and see, have ordered another just in case from Car Builder Solutions as they are good at returns
Cheers
 
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