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Forum Index => Refrigerator & Freezer Repair => Topic started by: JWWebster on April 15, 2011, 10:52:24 AM

Title: DCE33A-1WB Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 15, 2011, 10:52:24 AM
I have the service manual provided by Scotsman. It does not give low side pressures other than maximum operating pressures which is 30PSI low side and 265 hi side (Uses R134A). This is not the correct running pressure is it? I bet jumpy knows this one. These photos was taken last night. It is been running all night not nary an ice cube in there. Got good spray, good water supply, am thinking this puppy needs a charge. The water is cold so I know it has some gas in there. These dang ice machines are tricky. How much should I add or should I just go by amp draw? Click on pictures to enlarge.
Title: Re: Scotsman Ice Machine low side pressure?
Post by: jumptrout51 on April 15, 2011, 12:30:42 PM
Most of these machines start the freeze cycle at about 45 # psi and pull down to about 22 psi when the cube is about finished.
Your TEV is probably bad or needs remounting and insulating.
Place a thermometer in the water trough. It should be 30-31 degrees.
Check the water inlet for warm water leaking into the trough after the trough is full.
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 15, 2011, 01:06:48 PM
I will shut off the water supply, check the expansion valve and get back to you on that.
Title: Re: Scotsman Ice Machine low side pressure?
Post by: krazytech on April 15, 2011, 08:19:05 PM
I have not work on the scotsman ice make .. but I have done many of the subzeros ice make made by scotsman.

The Low side 1-5 psi at the end of the freeze cycle.
The High side at 125-150 psi

normal compressor at 4amp

Hot gas valve have a high failure rate...
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 16, 2011, 03:38:13 PM
We have ice cubes Baby! Photos coming!!
Title: Re: Scotsman Ice Machine low side pressure?
Post by: krazytech on April 16, 2011, 03:46:50 PM
Cool JW,
let us know what you found to be broke...
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 16, 2011, 03:49:31 PM
After I installed the tap I turned her on and it was way into the red zone. I SLOWLY added freon until it stayed at around 1 PSI and the amp draw is 1.5. After 20 minute BOOYAH! she jumped into harvest mode and dropped some cubes. Click pics to enlarge:
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 16, 2011, 03:53:34 PM
More raw footage from the swamp:
Title: Re: Scotsman Ice Machine low side pressure?
Post by: krazytech on April 16, 2011, 04:00:23 PM
JW,
So where is your leak?
Title: Re: Scotsman Ice Machine low side pressure?
Post by: jumptrout51 on April 16, 2011, 04:14:52 PM
This one of those OLD machines.
Title: Re: Scotsman Ice Machine low side pressure?
Post by: krazytech on April 16, 2011, 04:26:24 PM
Old but Scotsman still selling the same design ..
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 16, 2011, 06:30:37 PM
Ain't found a leak. Just figgured it needed a tiny bit. I might have added 1 ounce at best.
This one is harvesting ice every twenty minutes. The compressor is at 1.5 amps always and After harvest the pressure starts at 10 PSI then progressively drops over 20 minutes to zero PSI, then purges water and dumps big fat purty ice cubes.
Title: Re: Scotsman Ice Machine low side pressure?
Post by: krazytech on April 16, 2011, 07:55:22 PM
Does it have a info tag on it ... the subzero take 5 to 5.5 oz ..
Title: Re: Scotsman Ice Machine low side pressure?
Post by: krazytech on April 16, 2011, 08:03:23 PM
Do you get frost back when the compressor first starts? I think you may need to add a little more gas...

BTW I just love when you hear the first batch of ice drop off the evapator cups...a sweet sound of success...
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 16, 2011, 09:58:50 PM
This dude holds 5 oz. I ain't gonna mess with anything because the cubes are fat and nice. Gonna let it run all night and then take a photo. You will see. Just came from out there. Machine is kicking em out at a steady rate of 6 every 25 minutes.6 fat cubes.
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 17, 2011, 01:34:53 PM
I just took a few more photos. I feel like the bin should have been full by now but an ice cube was on the sensing bar cause the machine is tilted slightly and all the cubes were to that side, so I feel like it probably shut down sometime last night.
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 17, 2011, 01:36:20 PM
A few more:

Note the copper sensing bar on the right side of the ice bin has a bin control thermostat probe inside it. As you may know, when the ice cubes touch that bar the machine shuts down. Sweet!
Title: Re: Scotsman Ice Machine low side pressure?
Post by: AJ on April 17, 2011, 02:58:44 PM
 O0
Title: Re: Scotsman Ice Machine low side pressure?
Post by: krazytech on April 17, 2011, 05:22:24 PM
Glad you have ice... how do you know how much gas you added to the system without using a charging cylinder?  how deep of a vaccuum was it in before you added gas?
Don't you still think you have a slow leak? most likely on the low side?
Title: Re: Scotsman Ice Machine low side pressure?
Post by: JWWebster on April 17, 2011, 06:23:14 PM
You could tell from the warmth of the back side of your hands from the condenser outlet air that the system was low of gas. The water in the tray was cold but not freezing my fingertips so I knew I had freon in there. From working on these in the shop I knew they were fickle so I figured I would add a little tiny bit at a time till I got it out of the negative. It was around negative 10 psi so it had some in there but it was running a negative vacuum. So I barely cracked open the valve on my hose and never let the needle go above 10 PSI. Adding freon fast will cause problems. Overcharging chokes down the compressor and damages reed valves inside them. By slowly adding the freon a tiny bit at a time and listening to the compressor taking note of the tones and various noises you can detect overcharging. It took about 3 beers to get it to hang in there around 5 PSI without going right back down inside the negative or red zone. When it changed tone and began to sing like a central unit does when the freon is right I stopped and waited about five minutes. When it eased back down to around 1 PSI the compressor shut down. Water began flushing the res and a moment later the cubes started dropping. This is not the first one of these I have worked on. Although it has been a few years since I worked on the last one (1995). If this machine had a serious leak their would have been no freon in there whatsoever. Adding an ounce of R134A may make it go for years or die quickly depending on how severe the leak is. We won't know that till she stops making ice again.