Isotherm ASU 3201 fridge - lights flash, no work

[GlennG]

Have an Isotherm ASU 3201 unit (I'm pretty certain that's the model - it fits the pictures on the Isotherm site). When it is switched on, the green and amber lights flash and it attempts to start but doesn't. Not sure of the age, but definitely more than 6 years.

Having a devil of a job to find someone who can fix it. Berthed in Chatham, Kent.

Any ideas:
- what's wrong
- who could fix it

TIA.

 

[pvb]

Have an Isotherm ASU 3201 unit (I'm pretty certain that's the model - it fits the pictures on the Isotherm site). When it is switched on, the green and amber lights flash and it attempts to start but doesn't.

Are you sure the green light flashes? This doesn't seem to be one of the fault conditions described in the 3201 manual.

 

[chrisbailey]

I had a similar problem in 2003. I telephoned Marathon Leisure ltd 0n 023 9263 7711 and they were very helpful in diagnosing the problem and sold me a replacement electronic unit which resolved the problem.
If it is not an electronic fault you may have had a loss of the coolant gas for which you will need a refrigeration engineer.

 

[GlennG]

Are you sure the green light flashes? This doesn't seem to be one of the fault conditions described in the 3201 manual.

Now I've finally got around to posting this, I feel a bit of a fool as I can't remember exactly...! (This has been one of those jobs that I've been needing to get a round tuit, so it's been a couple of months since I last turned it on.).

I'm pretty certain that it was the yellow and green lights that flash. The manual says "Error signal from electronic unit. Automatic re-start after 1 minute.". Has anyone had experience of this?

 

[pvb]

I'm pretty certain that it was the yellow and green lights that flash. The manual says "Error signal from electronic unit. Automatic re-start after 1 minute.".

The manual says this for the green light on and the yellow & red lights flashing. I'm not being deliberately pedantic, but these fault codes are fairly specific, and you won't get to the bottom of the problem unless you know for sure what the lights are doing.

 

[GlennG]

The manual says this for the green light on and the yellow & red lights flashing. I'm not being deliberately pedantic, but these fault codes are fairly specific, and you won't get to the bottom of the problem unless you know for sure what the lights are doing.

Oops, I'm beginning to feel a bit of a pillock here! RTFM and all of that.

You're right; it says:
"Green and flashing yellow" meaning:
"Low battery voltage sensor has switched off the system Automatic re-start occurs when engine is started to charge batteries again."

I'm 99% certain that it's both the green and yellow that are flashing. Definitely all lights are flashing - I need to confirm that it's not the red.

When I next go to the boat -- it's 90 mins from here -- I'll confirm everything. I'll also give the connectors a prod as it could well be some corrosion during the (cold) winter.

...

What's the symptoms of a loss of gas?

 

[GlennG]

Right; now have facts...

The green is on solid, the red and amber flash in unison. It makes no difference if the engine's running (e.g. the volts are higher).

The quoted fault is "Error signal from electronic unit. Automatic re-start after 1 minute."

Any ideas (apart from the obvious - replace the electronics unit)?


Is there any chance this could be due to loss of gas?

 

[charles_reed]

Have an Isotherm ASU 3201 unit (I'm pretty certain that's the model - it fits the pictures on the Isotherm site). When it is switched on, the green and amber lights flash and it attempts to start but doesn't. Not sure of the age, but definitely more than 6 years.

Having a devil of a job to find someone who can fix it. Berthed in Chatham, Kent.

Any ideas:
- what's wrong
- who could fix it

TIA.

Probably too low a voltage at the transformer (the compressor is a 230v ac unit).

I'd suggest you get in touch with Anders on 0046 480 15080 -they're the manufacturer - but make sure you have the flash-sequence exactly right, as there are about 8 different flash-sequences each of which means something different.

It certainly isn't low coolant.

 

[Captain]

Advice is Cheap

Your lights indicate low power usually caused by old or compromised wiring. Try putting a good battery next to the unit and run new wires to the battery. If everthing runs good, replace or fix your old wiring.
Use a voltmeter connected to the positive and negative inputs on the electronics module next to the compressor to read your voltage. If the voltage drops when the compressor tries to start, it is bad wires or battery.

These are 12 and 24 volt systems. Direct AC power of 230 volts would fry the whole system.

 

[pvb]

Your lights indicate low power usually caused by old or compromised wiring.

Errr... no, they don't. RTFM!

 

[GlennG]

Finally emptied the locker, climbed in and tried to get to the bottom of the problem.

All cables prodded and poked, so no edge problems.

The unit attempts to start the compressor which you can feel 'pulse' as it vibrates for, say, half a second. This happens a few times (3 ish) with about 10 seconds between each pulse. The fan starts up during the last pulse and soon stops. Then it pauses for what seems a minute.

Not sure its electronics. But then again, TBH, I haven't a clue! I was wondering about removing the unit and seeing if I could send it back to the importer for refurbishing. Not sure if they do that or if they have the facilities to repair it.

I'm not particularly keen on spending £250+ for the electronic controller if its not broken. Even less keen to shell out £900+ on a replacement unit.

Damn thing. I need a refrigeration engineer who can take this grief off my hands. Whilst here's there, the boat next to mine also needs his fridge sorting out. In fact I've heard of 3 or 4 in Chatham marina needing someone to look at it!

 

[GlennG]

Some debugging info that may be of interest to someone in a similar predicament.

It's an Isotherm 3201 ASU, which has a RED box containing the ASU logic. You can pull this box off of the system (disconnect the wires first by simply pulling on it. Then you can connect the wires onto the BLACK box after crimping up a short jumper cable. This allows you to run the compressor flat out with no thermostat.

Alas mine just pulses and stops; exactly the same as when the wires were connected to the RED box.

This apparently is highly indicative of problems with the BLACK box -- I think this contains a DC to AC inverter to power the compressor.

I was sent a troubleshooting document by Marathon Leisure (thanks. The process above is contained in the drawing. I'll post it later (can't now; system's being backed up!).


BTW, the RED box at over £250 is a .... hmm, well, how can I say this... rip-off. It's about the size of a fag packet and contains a simple PCB with a handful of cheapo components. The sort of thing that gives the marine industry a bad name.

 

[GlennG]

The troubleshooting document (word, .doc format - 120Kb).

Damn, the forum won't allow a word document more than 19.5Kb. That's Hello World sized!

I'll need to sort out another place to host it...

 

[GlennG]

The fix

After going through various faultfinding steps, the problem turned out to be the *black* control box. The 3201 ASU has two control boxes, the red one that does the voltage switching (and is an outrageous £270), the black box is an inverter as the Danfoss BD35 is a mains voltage driven compressor.

Black box cost about £120. Will Hayward -- the refrigeration engineer -- keeps them in stock as they fail so often. In fact he'd replaced one the day before.

Now all works.