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Old 07-31-2011, 08:37 PM   #1
Jan 2011
Winnemucca, Nevada
Posts: 1

Hey all,

I was just getting ready to brew some ale and went to get my fermentation mini-fridge to the right temperature. I am using a Johnson Controls digital temp controller (A419, prewired) with the set points below. I have the controller jumpered to cooling mode cut-out at set point as per the manual. The LED light on the controller is on indicating that the probe is calling for cooling, but the fridge compressor is not running. I checked the fridge and when plugged straight into the wall it works. For kicks I plugged one of those cheap ground check indicators into the controller where the fridge usually plugs in and it gives me the "open hot" error.

SP - 65 F
DIF - 4
ASd - 12
OFS - 0
SF- 0

Anyone got any suggestions???

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Old 07-31-2011, 10:45 PM   #2
Aug 2010
Galveston Texas
Posts: 177
Liked 11 Times on 10 Posts

I hooked mine up the other day right out of the box. The stock settings are what I used. Why did you have to jump the stock connection? If I remember the stock setting is what you want. I adjusted it to start cooling at 67f then it cools down to about 62f with two cornys and warms back up to 67f. There is about 10-12 minutes bewtween cyles.

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Old 08-01-2011, 01:01 AM   #3
Feb 2011
North Central, Ohio
Posts: 509
Liked 31 Times on 22 Posts

It sounds like an open hot lead. Since the controller is powered up ok, that means you have 120VAC on TB1 ok. Check to see that you have a jumper from TB1 "120" to TB2 "C" and check with a meter or test light to make sure you have 120 volts on TB2 "C". If you do, then you should also have it on TB2 "NO" when it's calling for cooling. If it's good there, then you must have a bad connection / open between there and the receptacle that you're plugging the load into. If you have 120VAC on TB2 "C" and not on "NO" when calling for cooling and you have it jumpered correctly for cooling cut-out at setpoint, then you may have a defective unit.

Sometimes the wire can look like it's into the terminal block and the screw is down and it's making good contact but it isn't, so double check that. I've installed a dozen or more of these (NOT the pre-wired versions) & never had one yet that didn't work out of the box...

Reason: additional info

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Old 10-25-2011, 12:57 AM   #4
Jul 2011
Charlottesville, Virginia
Posts: 237
Liked 19 Times on 15 Posts

My jumpers are set for cooling cut-in.

SP - 65 F
DIF - 4
ASd - 12
OFS - 5
SF- 0

If I did this correctly, it should begin cooling when it's at 69 and should not cool any lower than 60.

Anybody else have a different set up?

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Old 10-25-2011, 01:45 AM   #5
May 2011
Stow, MA
Posts: 18,920
Liked 3386 Times on 2521 Posts

Originally Posted by chaseruff10 View Post
[...]For kicks I plugged one of those cheap ground check indicators into the controller where the fridge usually plugs in and it gives me the "open hot" error.[...]
Of course it's going to give you an "open hot" error when the controller isn't putting power to the hot wire. Hopefully that was a really cheap spend...

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Old 10-25-2011, 01:58 AM   #6
dutchoven's Avatar
Mar 2011
SF Bay Area, California
Posts: 636
Liked 8 Times on 8 Posts

Unplug and check your wiring ... Here's what I used for wiring guidance:

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