A Mystery Manitowoc -

[Poodle Head Mikey]

This is a Q unit, maybe 600 lb. Water-cooled head, ten years old.

The operators say: we find it not running in the morning. Bine is not full. We switch it off. We fill it with water from a pitcher. We turn it back on and it runs fine - making ice.

It's on well water. Recently I have replaced the clogged water inlet valve, installed new water filters and rack, and installed a 10 micron pre-filter for well sediment.

The condenser water is unfiltered but the head pressure is always normal. And I have never found it off on the manual-reset HP control.

In the summer they had water pressure problems when lots of people were flushing toilets. But now it is winter, the bar is very slow, hardly anyone uses the toilets, the pressure is steady, and I increased their well pump pressure from 45 to 60 lbs. besides.

Last Thursday I was there and the unit was off on "excess harvest time". It's is spotlessly clean inside but did take it's time dropping ice - more than two minutes. I sprayed the cube molds with silicone and it then dropped the ice Very soon into defrost.

Is there anything else I can do to speed up the ice dropping?

Turning the switch off and then back on resets any board faults. But I just got off the phone with the manager and she claims that simply turning it off and then on agan does not refil or restart the machine.

They say they can only make it re-start to make ice by adding water to the sump by hand.

That makes no sense to me. As I understand it; the control board's water fill function works solely based on power to the machine and the water level sensor - when the level falls: the water valve opens. When the water level touches the sensor: the water valve closes.

What the hell can filling the sump from a pitcher have to do with that?

Any ideas?

[yotaman16]

in my experience take what people have to say with a grain of salt...They will tell u what they want.. Personally i would pull the charge and weight it back in with new gas just to eliminate that aspect of it.. then see if the issue resumes

[hvacpope]

it needs a new board and I have one for sale

http://hvac-talk.com/vbb/showthread.php?t=155437

[fuzzyj]

check the dump valve, may be partly open, also check the water regulator on the condenser, low head pressure will cause long harvest times, as well as hpr valve.

[pecmsg]

Recheck the level of the machine. I had a customer redo some tiles in the kitchen and knocked the unit out of level. Water would hit the sump level probe every now and then and it would never refill. When enough frost built on the plate the curtain wouldn’t open. 3 or 4 times I had to go back.

[yotaman16]

Any one have that manitowoc bulliten about the new thumb screw.. maby the machine thinks the water tray is full and its not but when they pour water in and turn back on she goes to town i will search for it i dont remember the models affected.. sorry thats the s model machines just found it

[cjcargo]

Recheck the level of the machine. I had a customer redo some tiles in the kitchen and knocked the unit out of level. Water would hit the sump level probe every now and then and it would never refill. When enough frost built on the plate the curtain wouldn’t open. 3 or 4 times I had to go back.

I've had this happen to me also, now it's something I check often. I often tilt the level slightly forward to help with the ice harvest. A trick I learned from a older tech on a old worn out Scottsman.

[fuzzyj]

check the dump valve, may be partly open, also check the water regulator on the condenser, low head pressure will cause long harvest times, as well as hpr valve.

pecmsg is right, after thinking further about this, your problem is strictly water related. As pecmsg states, no water or little water in the sump= a small amount of ice on the evaporator, not enough to move the curtain during harvest, harvest times out, instead of resetting by way of the curtain x 10 = extended harvest trouble code.

[itsiceman]

Still banging your head with this one A bad toggle (or loose ground) switch can give you all kinds of erratic symptoms I found one by wiggling the wiring in the control panel. The toggle had a bad connection and would act up instantly (but I missed it for something else previously). Also for the times with no error code stored have you noticed if the front cover has an indentation around the toggle switch area. Some older ones would turn themselves off if the front cover was bumped ( The cover plastic was smooth )

[itsiceman]

Last Thursday I was there and the unit was off on "excess harvest time". It's is spotlessly clean inside but did take it's time dropping ice - more than two minutes. I sprayed the cube molds with silicone and it then dropped the ice Very soon into defrost.

Is there anything else I can do to speed up the ice dropping?

Any ideas?

If all you did was slick up the evap plate and the ice dropped fine the plate is dirty or plating is trashed. Remove the water curtain while in freeze just before harvest. Let cycle into harvest with out water curtian on and let the ice drop. Then let the unit run the full 3.5 min with curtain off. The machine will cycle off(full bin).The plate will begin to dry up and you will see the crud. If it is white lime you can clean with I/M cleaner and nylon brush. If the deposits are red iron Good Luck getting it off without destroying the plating.

[desroches]

also i think that its should produce a sheet of ice every 18 to 20 mins and drop that sheet in at least 3.5 mins

[refertecbd]

This is why they changed the Q-Model and the S-model's Harvest failare safety to 3 times to 500 times

[Poodle Head Mikey]

Either that or I have been fired I guess. <g>

I think the water sump being empty thing is incidental to the unit locking off on "long harvest time safety". The unit just goes off when the sump is empty. The empty sump is just another bit of meaningless data.

Last time there the discharge line was barely into the 160's. I raised the head pressure to get it over 170. So far as I can remember - that's all I changed. So far - no further word. I gave all the bar girls my cell number and instructions to call me at any time so I'm thinking I would have heard if there was no ice. <g>