Author Topic: Some ACC testing  (Read 1879 times)

1980sdga

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Some ACC testing
« on: 12 April 2012, 05:47 PM »
It's getting warm up here so I'm shaking down the climate control.

It was 85 F today so I did some testing.

5 minutes of running:



Turned the wheel and 5 minutes later:



Turned it some more:



Then back to 65:



The whole test was over about 15 minutes.  The thermometer is an industrial thermocouple  hooked to a PID controller. The probe was positioned near the "sniffer" on the dash. It looks like it runs about 5 deg. warm.

Not bad for a 30 year old automatic system!

I love my car!
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

1980sdga

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Re: Some ACC testing
« Reply #1 on: 19 April 2012, 07:51 AM »
I've been doing some over the road testing using an IR thermometer and I've noticed that I'm getting response that is about 5 deg warmer than it should be.

Not a big deal but lately it's been in the low 80's here and when the thumb wheel is placed on "65" the system will begin tempering the air with heat when the cabin reaches the low 70's.

When it gets really hot here it won't be an issue because the AC will probably struggle to even keep up but I'd like to get it working correctly while temps are moderate.

I remember that Joe had an issue with this that was solved by changing amps so I may try out my spare. I was also considering adjusting the temp wheel pot but it was dead-on specs the last time I checked it.
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

koan

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Re: Some ACC testing
« Reply #2 on: 19 April 2012, 08:47 PM »
Wasn't an adjustment mentioned somewhere in docs posted here to match the wheel temp to actual temp?

Boogity, Boogity, Boogity, Amen!

Hemersam

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Re: Some ACC testing
« Reply #3 on: 20 April 2012, 03:22 PM »
May cabin temp NEVER gets down to 70 when it is hot here (Texas). I wish it did.
Hemersam

ckamila

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Re: Some ACC testing
« Reply #4 on: 20 April 2012, 04:57 PM »
What temp is at the side vents after 5 and/or 10 minutes? Isn't that the best place to measure?

chris
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

jbrasile

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Re: Some ACC testing
« Reply #5 on: 21 April 2012, 04:33 PM »
Hi Guys,

Been out of touch for a while, little vacation after 12 years, hehehe....


Jon, try a different amp to see if you can eliminate the 5 deg difference. If I remember correctly, the interior temp should be measured  at the driver's ear, not at the dash sensor. Also check actual air temps in the center and side vents against specs in the manual.

A perfectly working acc will keep up with very high temps even in extreme heat conditions found in cities such as Dallas, Houston or Phoenix. I remember driving both my 79 300SD and later my 1980 450SEL to Las Vegas in July and being perfectly comfortable.

Right now the 78 450SEL here in SP is blowing air at 25F from the center vents and around 35F at the sides, both measurements using an infrared thermometer. I haven't measured ear level temps yet but will try this week just for fun.

Tks,

Joe

1980sdga

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Re: Some ACC testing
« Reply #6 on: 22 April 2012, 07:27 AM »
Thanks for all the input!  Interesting that the temp should be measured at the drivers ear!  I had just assumed that the dash sniffer would be the best place to monitor it.

Never assume with an old MB  ;D  You'd think I'd have learned that by now!

I'm pretty happy with the AC so I'll probably leave it alone although over the winter I did notice that the system ran a little warm just by "feel".

I've been carrying a little IR thermometer in the car and spot checks reveal center vent temps in the high 30'sF and the compressor has been cycling in the evening. I believe the ETR shuts off at 36F.  Next week I'll check the side vent temps and post the difference.

I have little LED's mounted on the right side of the horizontal switch panel that indicate when either the compressor or auxiliary pump is on.  As if the ACC II isn't complicated enough  :P

Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

koan

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Re: Some ACC testing
« Reply #7 on: 22 April 2012, 01:45 PM »
I have little LED's mounted on the right side of the horizontal switch panel that indicate when either the compressor or auxiliary pump is on.  As if the ACC II isn't complicated enough  :P

Good idea. Something I was going to do but mount LEDs behind/in the empty "PRNDL" hole in the cluster for compressor clutch, aux fan, low charging volts and alarm. Maybe fit 126 coolant level sensor to expansion tank and a LED for that as well.
Boogity, Boogity, Boogity, Amen!

1980sdga

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Re: Some ACC testing
« Reply #8 on: 22 April 2012, 03:48 PM »
I too would like to put something in the PRNDL spot. That chunk of styrofoam bugs me to no end  ::)

I had considered an LED bar graph tach in that spot and switch my tach to the big clock. 

Figure it out Koan and I'll do it! I already have the crank trigger...
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's