# AFS temperature probe 'twofer'

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#### rv7charlie

##### Well-Known Member
Just in case there are any AFS EFIS users on the forum, here are a couple of tips for the earlier (3000/4000 series) models.

I needed an additional OAT probe for the installation of an AF4500 in my RV6. The temperature probe costs around $70 from AFS; I wanted something a little less expensive. While some other brands/models use simple NTC or PTC resistive devices which can be as cheap as a dollar or so, the AFS models in question use a 'current source' device. After a little 'speculative' research, I took a flyer at buying a couple of Analog Devices AD590 devices. It's a lot more expensive; I paid just over$20 for two of them, delivered.
I plugged one into the same point as my AFS temp probe, and the resulting reading was within 2 degrees C of the AFS probe. Note that this is a new install of an AFS AF4500, and neither device had been calibrated in the 4500's setup menu, so I fully expect the AD590 to be as accurate as the AFS probe.

Here's a pic of the AD590 next to the AFS probe.
2nd tip: several RV drivers, including a friend of mine, have discovered that if you mount the temp probe inside the empanage fairing, above the horizontal stab 'deck', the temp readings are quite accurate and there's no need to have another thing poking out in the slipstream, costing at least 0.07 knots. (And simplifying wire runs.)

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• afs temp probe.jpg
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#### BJC

##### Well-Known Member
I’ve found the tech support people at AFS / Dynon to be very helpful.

BJC

#### rv7charlie

##### Well-Known Member
I've found the support from AFS to be superb. Dynon, not so much, even though Dynon now owns AFS.

The previous post was in no way a criticism of AFS; just a way to save a buck or three if someone's on a tight budget, and a potential way to simplify an installation. If I'd discovered the fairing mount trick earlier, I wouldn't have drilled the hole in the wing of my RV7 project for the OAT probe.

#### BJC

##### Well-Known Member
I didn’t take your OP as critical; just sharing with other readers that I have found the AFS people ready, willing, and able to answer questions.

The last question about my AFS 5500 was about the loss of the AGL indication. The AFS tech support guy readily identified it as an incorrect setting in the GNS 430 W RS 232 output configuration which, apparently, was reset to a default setting during a data base update.

There are enough vendor complaints here that I like to post positive experiences when I have them.

BJC