Pressure Transducer testing on Air-Conditioner units.

Firstly .. its a bit out of focus in places due to my camera auto focus system falling over. Sorry but will replace it with V2 when possible. This is a VRF air conditioner transducer modified to accommodate an external DC power supply interface. I have used a manual hand pump to increase pressure to manifold gauges to demonstrate the feedback voltage supplied to the AC micro-computer by the transducer. There are two multi-meters to show voltages. If you ever test these , you need the pressure/voltage charts supplied in the manufacturer service manual. While it is only 5Vdc, access to the AC electrical panels will mean live work , it should be avoided where possible and only performed by electrically licensed and refrigeration qualified personnel. Contact your Air-Conditioner brand manufacturer for best practice and service advice.

[@rodneythomas8686]

Very helpful tutorial...thanks mate...

[@hg2.]

Thank you.
Thank you.
Thank you.
Other refer channels talk about these and assume you know what's presented in your video.

[@lifeinoklahoma6723]

Thanks I'm working on a commercial AAON and couldn't figure out how to test the head pressure transducer 👌

[@aaronlaishley8150]

Brilliant and informative. Thanks

[@whatwoulddennisdo7243]

Thank you

[@75marcoleon]

Thank you Dennis!!!

[@johnf3278]

Should I be connected it battery ground or sensor ground would it make any difference. Thanks

[@alvee2387]

My A/C blows warm air at idle and when I’m driving it blows cooler?

[@EATSLEEPFARM]

With if your signal wire is reading 5 volts all the time no matter the pressure? Compressor will not engage on its own but i can command it on with a scan tool.

[@whatwoulddennisdo7243]

The command voltage is referenced typically under 4vdc and the operation of outputs is governed by logic rules not just voltage inputs

[@EATSLEEPFARM]

@@whatwoulddennisdo7243 so could i have an open or problem with the sensor or board? Just doesnt make sense why i can command the a/c compressor on with the scan tool but it wont come on under normal operation. I have 5 volts all the time on my signal and ref wire. Never changes. But i can pull the signal wire down to zero by jumping it to ground. To me that shows my circuit is good but the sensor isnt doing its job. Im still learning and your video is the only tbing ive found on 3 wire a/c pressure transducers. Im trying to figure out a good way to test it without just throwing parts at it. Thank you for your reply.

[@whatwoulddennisdo7243]

The only way I can test these is with the manufacturers pressure voltage graph, all other issues come down to connections or applied rules if operation

[@jameswasher3938]

Would you mind specifying the transducer you used here? I'd like to view its spec sheet.

[@whatwoulddennisdo7243]

Hi... Look i got this one from scrapped units at work. I think it was an LG or a Mitsubishi VRF system. I don;t have its pressure / voltage linear chart. It works similar to models I do have charts for. The part will be generic from a common manufacturer. That being said the transducer was manufactured in Japan and I think it is Saginomiya industries.

[@jameswasher3938]

Thanks. I'm planning on replacing my R22 unit next year with a R410A unit. Since I'm an IoT nut, I intend to add some monitoring. High and load side pressures, Temp sensors, etc. to be able to do SH and SC calculations live. I will also monitor the compressor, condensor fan, and blower for current draw. I figure over the life of the machine, I may see some interesting trends.

[@whatwoulddennisdo7243]

Your in the right time for all such needs. Manufacturers are now providing point of origin sensors back to wireless controls which also includes transmission to an I-phone or Ipad / tablet. Check out Testo Gear , they have quite a range

[@jameswasher3938]

I'm familiar with the test gear, I'm talking about a permanent installation of sensors. It seems this is done on some commercial and industrial HVAC, but not much on residential systems. Even the so called "communicating systems" don't have what I want.

[@whatwoulddennisdo7243]

No your right, most domestic class splits do not even have pressure switches as they use logic with coil thermistors to act as surrogate HP/LP. Emerson controls have some transducer based HP/LP as do Danfoss, what is available on the commercial market may not be always suited to domestic use. The service gear has the sensors that can be placed into locations to provide your SH/SC or saturation info , If you left them permanently connected.

[@hg2.]

Thanks, but need a lapel mic.

[@davis37mail]

So blurry I can't watch it. Seems like a great video though

[@whatwoulddennisdo7243]

Yeh sorry, i did these in my lunch breaks