Manitowoc with gremlins

[rango]

This machine has been kicking my butt for 2 wks.

M#1394 remote condenser.

Problem intermittent.

1st call, unit not harvesting. Outdoor temp about 5 degrees. Liquid line from roof cold during harvest. Return following day with headmaster, pull charge and install , vac and recharge per data plate. Makes ice for three hours and I'm called again. Go in, hook up and harvest pressures running at 30psi. next day after talking with Manitowoc, install hpr valve and solenoid. Machine makes ice for 4 to 6 hours and trips up on error 2. Go back following day and stand in front of machine for 4 hours. finally catch board relay for hpr and left hg solenoid not closing. Valves not opening. Order board and install following day. Makes ice for 4 days. Called back, and hook up meter again, makes ice for about 2 hours and duplicates, so put in another board. This is after tracing and checking all wiring and grounds. Back to Manitowoc, talk to tech and he says replace thermistor with 26K resister. Once again. Machine makes ice, until... I leave. Go back this morning. Turn machine on and did other things in the store for the next 6 hours. Machine didn't f**t once. 30 minutes after I left, store calls ad says plate double frozen. Had them wait till it fell off and told them to restart. That was 3 hours ago and still working. Anybody have an idea what in the H E double toothpicks could be causing this thin to intermittently forget to open the valves? I threatened the manager with hanging my picture in font of the thing, since it works like a charm whenever I'm in front of it.


Thanx,
Rango

[itsiceman]

Maybe it has nothing to do with all that other stuff For the ice thickness problems check that all the screws are in the distro. tube at the top and that the top evap. plastic doesn't move up or down off the top of the metal part of the evap.

[coolerfixer]

and it turned out to be the suction accumulator of all things. The j tube wasn't soldered so the refrigerant eventually all ended up in the acc. I just replaced it after doing all you've gone through and presto, all better for over 2 years now.

[tnbasshunter]

I agree with iceman. With the intermitten thickness issues sounds like the thickness probe is having some issues. I would check there.

[rango]

Not a thickness issue. Intermittently, left hgs and hpr will not open. When this happens, harvest times out and machine attempts to freeze again. Since previous harvest failed, thickness probe is pushed out just a bit and never will contact water or plate or anything else. If after a period, I short out the probe, it will induce another harvest and drop. Then go hapily on its way for another 2 hours to 3 days. As I said, left side valves fail to open intermittently (the board relay doesn't close) that's if I take voltage from wire 90 on the 9 pin to L2.

[itsiceman]

Is this a B With original control board? I don't know the numbers by heart. Sorry I don't have specifics any more just what's left in my head and parts are not in the service book.

First change the water curtain switch on the left side. It may be going bad and sensing the ice dropped on the left before it does "intermittently' (and to compound the problem no ice probe on the left). The board drops power to either side that drops ice first and continues with one HG valve
(garbage in garbage out).

The part that is fuzzy for me is the dual evap B board used the thermistor to control the hot gas valves operation too but I don't know how or at what temps (This part is not in the tech book). Fooling the board with the resister might have covered up a system problem and is messing with the way it was originally designed.

My guess would be the water curtain switch since it is intermittent or, maybe it is Gremlins

Don't forget the three rules: #1 Keep them out of the light #2 Don't get them wet #3 Definitely don't feed them after midnight

[Tranetech]

Check for a good ground and good elect. connections.

[jonbailey19808]

did you get it fixed Rango?

These guys are really good.

[idontgetit]

Ok, so now you are married to it.

I hate that but you have covered about everything that comes to the top of the head from the info provided.

One thing I do when a mani has a fit, amp clamp on comp, multipule temp probes on discharge, lline, suction line, and slap the gauges on, record all the readings every minute until 80% of freeze is done and then every 30 seconds. Then I call mani and sometimes you have to motivate them a bit to listen but most of em are real good about it and you will get good feedback.

If the solenoids ain't opening then you gotta find out if getting voltage, if not why aka board output which sounds like you have done, have you done it again on new board?

good luck

[rango]

Ok, so now you are married to it.

I hate that but you have covered about everything that comes to the top of the head from the info provided.

One thing I do when a mani has a fit, amp clamp on comp, multipule temp probes on discharge, lline, suction line, and slap the gauges on, record all the readings every minute until 80% of freeze is done and then every 30 seconds. Then I call mani and sometimes you have to motivate them a bit to listen but most of em are real good about it and you will get good feedback.

If the solenoids ain't opening then you gotta find out if getting voltage, if not why aka board output which sounds like you have done, have you done it again on new board?

good luck

Dropped in on Monday aft and they had the machine off, so I stuck on some coils for the hot gas valves that I had in the truck as an interim measure while I ordered up some solenoids. Lit it up and stopped by each day through the week if I was near the store. Bin full. Was just going to post that I got it, thinking that one of the coils was causing it. But, 2 minutes ago, manager called and said unit failed right harvest.

As to all the suggestions, over the last couple weeks I have checked and/or redone all connections and grounds. Voltages checked and double checked. Amps pressures, etc. Is it possible that one or the other hgs is sticking intermittently? Thoughts? Thanks.

[itsiceman]

Thoughts?

Maybe when all the stars and planets are aligned a dirty screen in the discharge line (at the manifold where the pressure switches are) is causing harvest problems.

[rango]

Since I won't see the demon machine till tomorrow could you tell me how a screen could be dirty one cycle and not for another 8 or 900? I am curious if you have any theories. Just something to kick around til I can get back there. I know a lot of things can happen that defy logic and reason. The store manager wants my picture so she can hang it in front of the machine, cuz it refuses to screw up wen I'm there. I'm thinking that someone has a voodoo doll of a B machine and occasionally pokes a pin into the hgs.

Thanx ice.

[Makinice]

This sounds like the same machine that drove me nuts about a month ago. Except it was a Q.

Same symptoms as yours. I did everything you did (except the board). I ended up replacing both hot gas solenoids and coils.................. and the problem went away.

I feel for ya.

[itsiceman]

Since I won't see the demon machine till tomorrow could you tell me how a screen could be dirty one cycle and not for another 8 or 900? I am curious if you have any theories.

I was tring to think of something else that you haven't changed yet Stuck crud could be getting loose and then clearing the valves When you change the valves and filter drier you might change the screen anyway because it's no big deal at this point. If you can't get one today you may be able to see inside if you open one end.

[jonbailey19808]

Rango: Record as much info as you can and call Manitowoc

Suction and discharge start middle and end of freeze

Suction and discharge start middle and end of harvest

hottest temp the discharge got to in freeze

Liquid line temp

Temperature diff through evap 5 mins into freeze

Freeze time

Harvest time

Then call 1 800 545 5720 with your model and serial number

Try and call as early in day as you can.

[idontgetit]

Well your post IMHO is a classic description of an HPR failure, an intermittent pain in the hind end, but you have stated you have already replaced HPR so I am kinf of lost.

I have never seend the sporlan/dan foss replacement kit fail, not once. The old alco ones were common. Did the hpr kit you put in have the danfoss/sporlan parts, or was there an old alco kit laying around?

Uhm, no intent with this one, but you know them dan foss valves with the stainless tubes take about 1/3 the heat of a copper tube right? I have never burnt one up myself ut have found it best practice to heat the copper going into it instead of the stainless itself.

I guess a coil could be cracked and get moisture in it and cause some intermittent crap but without being in front of it, or in front of it this one is a hard call.