Hoshi KM1300swf no ice

[cfcitywide]

Found unit tripped on 3 beeps long freeze cycle
Reset and...
Unit pressures @ start -up
head 275-300psi (floating and water reg banging evry 10 secs)
back 50psi
low discharge delta (70* water discharge)(60* in)
10 mins into cycle the head stabalizes @ 270psi and the back drops to 15psi
Both evap decks are frosting identically. Frost up to the firstbend on each evaparator then return line temp at 42*
No delta accross the drier
comp rated at 9.7amps pulling 7.5 @ start-up 10 mins in 5.2
no ice formation on evaps at all.

[DoctorIce]

Looks like moisture in the system blocking TXV.

[cfcitywide]

That's crossed my mind and I considered changing the POE oil,drier and puliing a good 500 mic vac but the customer insisted that the unit work fine before it was moved to it's new location where the prob originated. It seems odd that both valves would freeze up at exactly the same time and exactly the same restriction amount

[cfcitywide]

I neglected to metion a key important part
The 1/2" tube is pinched severely at the backflow preventer (outlet to condenser)
I have a good volume of discharge water (aprox 3gpm) but again the delta is low.I'm inclined to turn the water reg valve down tomorrow but the head seems normal where it's at. I'll try to get a 105* discharge temp.

[cvas]

You'll want 5 gpm for the KM1300. Also, check pressures 5 minutes into freeze cycle. Should be approx. 265 and 46 with 60 degree inlet water temp and 70 degree ambient temp. Adjust water regulating valve to 106 degrees. I also would suspect crimped water line building up pressure and releasing causing hammering in regulator.

[refertecbd]

Check inlet water valve daiphram. Float switch and clean the machine

[hvaccolo]

refertecbd is probably on the right track. I would focus on the potable water side. Hosh is notorious for those little plastic bits from the diverter plates breaking off and jamming in the dump valve, pump, etc. Check what your water level is doing in the reservoir. If you're not making ice, but the water level is dropping, that's what your problem is...

[cfcitywide]

In the event that I was losing water it seems that I would still be getting an evenly frosted evap? Which is not the case. Both evaps are frosting only up to the first bend. The outlet on the evaps are 42*

In fact the unit doesn't go into harvest which is initiated by the float switch opening. I found it on a hard lockout due to long freeze cycle (3 beeps).

I think I'll reclaim, vaccum, add drier and wiegh new charge and start from there
I'll let you know tomorrow what happens

[DoctorIce]

I think the key factor is the suction pressure drops to 15 only 10 minutes into the cycle. If it was only a water problem the evaporators would freeze up with no water or the suction pressure would be high if there were water constantly being added. It sure looks like a refrigeration restriction somewhere to me.

[cfcitywide]

Started from scratch yesterday. Reclaimed the 404A and ran a vaccum for 30 mins then did a hold down test to see if there were any obvious leaks. It went from 30" to 28" in 10mins and stabilized there for 30mins before I continued the vaccum. After aprox 1 hour I noticed my sight glass on the pump actually condensing moisture on the glass and the oil was milky. This unit must be saturated. The pump has been on for 24hrs and I won't be able to return to the site until tomorrow. Unfortunatly my micron gauge is broken. Which would be more effective for moisture removal liquid or suction drier. I suppose I should pull the compressor and change the oil?
I noticed some rough looking welds and the owner stated that the last tech had it making ice but it sprang a water leak and he attemted to make some additional repairs and said he would return but never did. I'm wondering if water was introduced in the system this way It's a water cooled unit but the unit pressures were 275psi & 50psi at start up. I suppose the only way to tell is to get a visual on the oil? Any thoughts

[DoctorIce]

I would make sure the previous tech hooked up the water cooled condenser correctly. I can't see where else all the water came from except perhaps wet recycled gas. As for getting rid of a lot of water you probably have to pull the compressor out, drain it, and put in fresh oil. It sounds like its too much water for just a drier to remove.

[wannafreeze]

I found a condensor coil leak at the drain while the machine was running(head pressure up).When the suction dropped like in your situation I heated the TXV to confirm the moisture in system.And did my customer a favor,had them scrap the relatively new machine and buy a new one.Don't try to take the moisture out,sell them a new machine,they will be saving money.These issues were discussed at this forum..

[cfcitywide]

Returned and found the vac pump oil was nice and clean and had a good deep sound (again need to replace my micron gauge) aDDED A HUGE 164S Danfoss LL drier and charged w/ virgin 404A ( how much refrigerant should be added to compensate for the oversized drier?) unit fired at 265psi and 50psi and back came down to 40psi after 20mns run time. I could not frost the last rows of each evap plate so I pulled the txv bulbs and it took off Checked compressor s/h continuously through 4 cycles and it never went below 20*. Thought both valves might be bad due to the moisture but I did have frost up to the bulbs so I may have over charged (pressures seemed dead on).Left and returned today 3/4 bin of ice (800#s)found it in hard lock out(1 beep) >129* evap time. I belive it timed out on defrost. Reset and observed the HGV stuck in the open position. Disconnected molex to interupt solinoid power and it was still wide open. Any ideas on what may have caused wide open failure. Also noticed a lot of cold fresh water dumping on 1st start up via the bin drain circut which I had to isolate from the condenser water circut from previous tech. I read that there's a check valve that may be dirty but I can't located it.