Fridge trouble

  • Thread starter Thread starter prv
  • Start date Start date
nigelmercier said:
Did you read the rest of Post #14, the bit about when the engine is running.
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More than that, I've read the whole manual.

It runs in freeze-the-holding-plate mode when the supply voltage is above 13.2 volts - whether due to engine running or shore power being plugged in (which it was).

When the voltage is below 12.7 volts, it's regulated by the thermostat - if the plate is above -1ºC (which it was) it runs the compressor at a lower speed until the plate is brought back down to -6º (but doesn't try to freeze it)

So either way, with a room-temperature holding plate, the compressor should have been running.

Pete
 
nigelmercier said:
And no luck from the fault finding section or the diagnostic LED?
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Not from my desk at work, or my house this evening, no :)

Will have to wait till the weekend for me to go and look at it again.

There's no diagnostic LED on this kit though. Presumably there are terminals for it if I were to pull off the red Isotherm controller.

The so-called fault finding section is fairly useless in this case. No sign of life? Check it's turned on and that the fuse hasn't blown. Well, duh, I did that as soon as I realised wasn't working.

Pete
 
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prv said:
There's no diagnostic LED on this kit though. Presumably there are terminals for it if I were to pull off the red Isotherm controller...
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OK, but the manual mentions it. Removing the red interface box was going to be my next suggestion anyway. You will need to look at the relevant Danfoss "Electronic Unit" controller manual and bypass the thermostat. They are very similar, but if you can see a Danfoss number (starting 101N...) it would help. See here: http://www.danfoss.com/United_Kingd...unit&IncludeCurrent=True&IncludeArchived=True
 
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prv said:
Really? Where? A search for "diag" or "led" finds nothing. The only mentions of "light" refer to the three lights on the control panel, which as I stated in my original post, do not light up at any point.

Pete
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Have been reading this thread with interest, as I have just finished a fridge/freezer in build, if you check out Nigel’s link to Danfos, I think you will find this link helpful.
http://www.ra.danfoss.com/Technical...t_101n0290_12-24vdc_08-2011_dehcei100w302.pdf
Will show you what type of LED to buy and how to fit it for the diagnostics. I bought one for my set up but can’t find the invoice at the moment.
I think you will find that most compressor units irrespective of supplier are built around a Danfos compressor/Electronic control unit with just additions?
 
prv said:
Really? Where? A search for "diag" or "led" finds nothing. The only mentions of "light" refer to the three lights on the control panel, which as I stated in my original post, do not light up at any point.
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Sorry, "Indicator lights". So none of them come on? In that case, suspect a bad connection or the red box.

It seems the link in my post #9 has died, see here for manual:

http://www.indelwebastomarineusa.com/Download_area/us/html/10275.html

http://www.indelwebastomarineusa.com/Download_area/graphics/17_Download_Area_Manual_ASU3201.pdf

xeitosaphil said:
... Will show you what type of LED to buy and how to fit it for the diagnostics...
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Any LED will do, with a 2k2 resistor to get 5mA. But if the green LED isn't coming on, it isn't going to work.
 
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nigelmercier said:
Sorry, "Indicator lights". So none of them come on?
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Errm, no. I thought I made that perfectly clear in my initial post - "there was no sign of life", "no apparent activity from the fridge - in which I include movement in the compressor, coolness of the plate, or lights on the controller."

nigelmercier said:
In that case, suspect a bad connection or the red box.
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Mm - as I've said (broken record here :) ) I measured somewhere very close to 12v on the input spades to the red box, while running a shore power charger, and with no visible corrosion on the connectors. So I'm fairly confident the red box is getting power. Obvious next step, as we've all realised, is to unplug the red box and go straight to the Danfoss controller. Just to confirm Biljratt's memory, do you know if the Danfoss thermostat connectors should be shorted or open-circuit to cause the compressor to run?

I will also try the diagnostic LED terminals.

nigelmercier said:
It seems the link in my post #9 has died
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Not really died, just picked up some spurious characters on the end. If you delete back to "pdf", it works fine and I have, as stated above, thoroughly read it and printed a copy to put on the boat.

(It didn't really say anything that wasn't in the separate manuals for fridge and ASU system linked in my first post, but it's handy to have a single book rather than pieces from two, so thanks for finding that.)

Pete
 
prv said:
Errm, no. I thought I made that perfectly clear in my initial post ... Just to confirm Biljratt's memory, do you know if the Danfoss thermostat connectors should be shorted or open-circuit to cause the compressor to run?
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Sorry, missed that bit of your first post; mea culpa.

I'm 99% sure that the thermostat is a NO contact, it is shown that way in the Danfoss manuals. So you need to short C and T (as I originally said before I noticed the red box, and found the other picture).
 
Ok, update.

Before doing anything, I unplugged the Isotherm box to leave just the standard Danfoss controller (101N0200, from memory). I applied power, reading about 13.5v on the spade terminals. Connected C and T together, and put the multimeter on the diagnostic terminals (forgot to bring an LED). Still no sign of life whatsoever. I tried the same after disconnecting the controller and putting it on the bench, powering it from a pair of croc clips on a known good supply. Still nowt.

Looks like a knackered controller, I guess. Unless there's a fuse in there? Does seem a bit odd for it to just die like that.

Pete
 
Ok, finally got my hands on new compressor controller this evening, and got down to the boat for a quick try. Still no joy.

However, I did get the multimeter probes on the actual terminals while it was powered up, which I'm not sure I did before (two bare terminals in a small awkward space, I was worried about shorting them together, so I may have only measured the supply voltage while disconnected). A healthy 13v while disconnected, but only 2 or 3 with the Danfoss controller plugged in.

I assume this indicates a poor connection in the supply wiring? It's not something the controller could cause without pulling an unfeasibly massive current, right?

Silly me for not testing the supply under load. When I tested with my known-good supply I guess the controller declined to function because it knew it wasn't attached to its compressor, but to me it looked like proof that the problem was not with the supply.

Pete
 
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