manitowac series 420 ice machine help

[verlie's]

We have an older, (early 90's) ice machine we call it Lazarus because it has risen so many times from the dead.
Usually Lazarus just needs a cleaning, and his coils blown out and he starts working again.
we have unplugged it to reset it, cleaned everything, and it's not working.
The "harvest light, safety limit code light" is blinking continuously, it should be flashing a number that corresponds to a code.
it will go through the clean cycle, then we try to run it normally and it stops, and the light starts blinking.
A friend who has some experience with this says that it is going into harvest cycle too soon. and that the ice is not forming, but the ice censor is telling it that ice is forming, so it is bypassing it?
he knows something about ice machines, but is not computer savy, so I am trying to convey what he told me. i am am not ice machine savy, but am familiar with the internet.
The last time this happened the same employee, "cleaned" lazarus. i think she may have sprayed alot of coil cleaner in there, not sure but as long as I was cleaning it, it always ran fine again.
Any ideas, or help would be much appreciated.

Thank you

[philfridge]

When machine runs how long does it run before going onto harvest cycle ?and what is happening inside machine ? Any ice what shape ?

[verlie's]

it goes into harvest, fast. roughly 5 or 6 minutes. no ice at all.
Something I forgot to mention is the water company was working on the mains down the street, and they cut the water off. when the water came back on,we started it on clean cycle, and you can hear the water going through it, but it hasn't worked since.

[al]

Looks like a faulty ice sensor or someone has pushed the sensor too close to the evaporator, this will prematurely short it out.

al

[verlie's]

I talked to my guy and he said he tried by-passing the sensor, and it timed itself out and went straight into harvest. i can try replacing it, I don't want to keep buying parts if we're not sure.
The trouble started when they turned the water off.
No one thought to turn the ice machine off.
When the water first came back on, it was sputtering out of the faucets, then returned to full flow.
we ran the clean cycle on the machine at that point, and it seemed to be normal on that.
Any other possible solutions, that would be connected to the water being shut off?
Also that light just blinking continuously instead of in code.

[fridgey]

What series is it? You say 420 but there is a letter before the 420 which indicates the series. From experiece it's more than likely the ice thickness probe is the fault. I would replace this as a starting point.

Cheers