stumpped over a scotsman ac125

[Colin G]

been looking at a scotsman ac125 earlier tonight, its not producing much ice, its ran fine for the last 10 years but has recently started to produce next to nothing, with it being so old i dumped the gas vaced it out and gave it a fresh charge of gas

now the evap is getting cold enough to start forming ice but after its cycle it drops ice shells hollow, now looking on the documentation on the website it would appear its not getting long enough on the second stage of freezing.

stage 2 freezing timer can be altered by the dip switches on the pcb, what i dont understand is why after 10 years it suddenly isint performing.

- getting a good 2 psi suction pressure near end of cycle
- discharge around 9 - 10 bar

going to check maybe extend the stage 2 tomorrow but wondering if anyone can suggest anything as i havnt really worked on these although they look rather simple in design im still confused

[Brian_UK]

Is the evaporator clean and scale free ?

[Colin G]

to be honest it has slight scaling on the coil

[Latte]

As Brian suggested the first thing i would do is a desclale. Its easy on these, just put the cleaning fluid in a put it onto a clean cycle for 30 mins. Then if you have one, use a round paintbrush, dipped in cleaner to manually clean out cube tray.
When you run it up keep an eye on the red light on the board (Labeled -12 or -15) once this light comes on the timer for the freeze cycle comes into effect. If you have a faulty evap probe or getting a poor reading this affects the freeze timer (either starts too early or doesnt come on and you use all the water)

Hope this helps

Regards

Latte

[Colin G]

will do a descale tomorrow, might also go armed with a replacement probe just in case, what probes are fitted to these?

[Latte]

Im afraid they are scotsman probes, not interchangeable with another make. Keep an eye on the numbers on the probes (They are marked on the probes) if memory serves me right the condenser probe is 620404-10 and the evap is 620404-11 unfortunatly you cant change them to check as the resistances are different

Regards

latte

[Colin G]

hopefully have one sitting in the work :D thanks very much for the help will let you know how i get on tomorrow.

What actually happens in the first part of the freezing stage up until the evap probe kicks it on to stage 2?

[Latte]

Its a bit long but this is the link for a download of the manual. you may be able to just pull the pages you think you may need

http://www.scotsman-ice.co.uk/pdf/Service%20Eng%20Data%20Manual.pdfd


regards

latte

[Andy W]

Are the cups still attached to the evaporator?

If you study the lights if the dip switches have always been ok before they would not fail now, the lights will tell you what phase of the cycle you are on and if it does not reach the required temperature in the pre set time then it will trip, if it is not tripping (you have to restart the machine or turn the black knob to srestart and cut the 4 min fill cycle off) then you have a problem else where.

Are the water spray jets ok and not squirting water out sideways from the spray jet plate (gaskets wear) also clean the mesh guard which sits under the pump.

[lowcool]

yep sounds like water problem to me had something similar found the plug on the end of the spray arm had fallen out.

[Yuri B.]

Scotsman's water side is easily disassemlable. Everithing what is in contact with water is taken apart, left in descaling solution for a day and then rinsed. This done every year or two at least, depending on load.

[thebigcheese]

is it running out off water before end of ice cycle? check water dump valve for passing

[Colin G]

ok update


went over tonight and changed the evap probe, and now its producing plentyful ice! looks to me as if it wasnt getting long enough on the first stage of the freezing cycle which is controled by the evap probe. Also poured in some descaler and let it clean its self for half an hour.

[Colin G]

this unit has failed again, different fault now, all the warning lights come on in series, and in order the following happens

- water starts pumping then cuts off
- compressor kicks on then off

then repeats over and over again.

[Andy W]

Your problem now is someone has turned the black reset switch and it is in test phase to check each component, sounds like someone has had a mess. Reset the switch.

[Colin G]

they have bought a new ice machine as they dont want to spend any money on this, im thinking about buying this of him and refurbishing it, then selling it on ebay for a little turn around.

[Colin G]

phoned up hubbard today for some advice on this, and he said it sounded like a pcb fault, so found a controller and replaced it earlier, had to cut a resistor out so it would work with the compressor contactor and away it went. Needs new water jets now though as they are leaking out the sides! one thing after the other :D