So who here is good with ice machines?

[mmemalaysia]

Been working on this machine for a couple of days...it is a fairly new machine usage wise...took it out of storage where it had been pumped down and piping to remote was disconnected and couplers were all taped up to prevent contamination..seems like everything was done properly. So i set it all up and remove the charge ,cause who knows how much was left in and i would rather start with a weighed in charge to be sure. OK..so i weigh in the measured charge of 8 lbs and turn it on and it makes ice no problem..although the high pressure was a little low ....nice even pattern on the coil...but ,when it comes to harvest it wont drop the load cause the hot gas is only going half way thru the coil and the machine times out on the 3 1/2 min for harvest..the pressures are low in harvest...so i figure it is just a low gas prob. so i top up the gas to the point where the high side is 30 degrees above ambient for the condensor 85 deg air intake 285-300 PSI for R404. I figure maybe this is a little high but try it out anyway.OK so the ice formation is still ok but the harvest is still about 2 min and the pressures are still low..low only reaches 75-80 as apposed to 83-96 per the manual. Is this a problem with the HPR or the High gas valve...kinda got me stumped...any suggestions

[chillin out]

Does the cond fan stop when it goes onto harvest?

Is there a pressure switch for the fan?

Is the hot gas valve opening properly?
(stick a magnet on it to check, sometimes the coils go weak)

What make is it?

Chillin

[old gas bottle]

hate the misrable things, but me thinks the same, hot gas valve is a start, when in harvest the cond fan stops,high pressure should drop and suction go right up,wiegh the charge back in,dont guess if its on the plate, other thing is they dont like cold ambient temperatures,is it in a cellar??

[mmemalaysia]

Sorry ...guess i should have given more info!

Machine is MAnitowoc JY0694N, remote condensor so there is no fan cycle,average ambient is 85 -90...solenoid valve seems to be opening properly, getting hot gas to the coil...just not enough.

[chillin out]

Is this the one..


Have you actually put a doughnut magnet on the valve to make sure it lifts propely?

The drier is not blocked is it?

Chillin

[knkreb]

Manitowoc is my favorite. The harvest cycle needs gas, but it doesn't have to be super hot huge quanity of gas either to melt it off of the plate. The gas cools very quickly after enters the evaporator, and then begins to condense back into a liquid. The latent heat transfer will help melt the ice off.

The pressures don't appear from a distance to be "that" far off. You may just be within the operating tolerances slightly. There seems to be little bit of "fudge factor" to some degree either side of the specificiations found in the service manual.

You may not be fighting a refrigerant issue, but more of a release issue. What is the condition of the evaporator plate? Does there appear to be any damage or loose rows within the evaporator? Are there any spots on the plastic edges of the evaporator where someone may have melted it (some genius trying to melt ice off the plate)?

Just a few ideas from a fellow that banged his head a few times chasing down long harvest issues.

[phil68]

The majority of machines that I've come across with ice dropping issues have been due to scaled evaporator plates -the scale makes the ice stick very much like when paint adheres well to a keyed surface. Try running some descaler through the machine & see what happens then

[mmemalaysia]

OK ...thanks for all of the input...turns out i was dealing with a bad HPR valve...changed the puppy out and gettin ice like crazy now!!!

[clab]

i recently had a b model that had weak discharge valves wouldnt create enough pressure to get the temp high enough to melt ice from evap. freeze cycle pressures were ok just under specs. added charge with no difference. manitowoc says 8-10 years is the avg life of a system. j model been around for a while.