Very old GE Monitor Top - Scrap saved....

[turbokinetic]

Check out this little General Electric Monitor Top DR-1. It was given to me after a friend acquired it and found it nonworking.

The DR series was the original Monitor Top design produced from 1927 to 1932. They have the open coil condenser on top and intricate clockwork controls. The most collectible, but also the oldest and least refined design - these are often used as storage cabinets and interior decor once the cooling system becomes nonfunctional.

I want to see if this one can be brought back to life so I did some troubleshooting and documented the findings in videos.

Part 1:
Part 2:
Sincerely,
David

 

[retro-man]

Again, I always love watching your videos. Amazing to see such an old unit brought back to life by you. Most people would have kicked it to the curb as trash. Something this old is still able to run properly with your knowledge, is incredible. Also a testament to how things were made back in that time. Keep up the good work along with the videos.

Jon

 

[turbokinetic]

Thanks Jon!  They definitely put a huge amount of engineering effort into these units. The DR's are especially fascinating because of their being the "first" version, and the "overall uniqueness" they possess. 

 

This model was introduced just one year later than the Frigidaire M52 belt-drive I'm also working on. It's so clearly a massive leap in a new direction that it's no wonder they over-engineered it so much. Everybody is afraid for their new design to be perceived as a failure due to small problems that turn into big headaches.

[this post was last edited: 11/12/2019-10:24]

 

[sfh074]

Question ....

David, how do you establish the amount of oil that a unit would need? On acquiring a project like this and not knowing how much oil is already in the system and not knowing what the factory established amount actually is called for, how do you come up with the minimum amount that you think is good for the system so it doesn't scavenge for oil? Do you have some way of determining based on system shape and size?

On my '55 Philco I never found documentation of what the factory oil charge amount should be. What I did was uninstall the compressor and flip it over to catch the oil that was already in it and measured the amount. Next I took acetone and flushed out the remaining condenser and evaporator loop and caught the used acetone. After letting the used acetone sit in the sun and evaporate, their was another 1.1 ounces of oil recovered. I then replaced the total measured amount of oil with fresh oil. This is probably a very close amount of the required oil for this system .... especially when you compare it to known similar refrigerator requirements, the amount I recovered was comparable. But I still wonder if there was oil loss due to previous work or maybe someone thought it needed additional oil and added more. Who knows what took place before I got this fridge.

So in knowing what I did and measured the oil I replaced, do you have some other method, as asked in my first question to you above, do you have some other way of interpreting the amount of oil a system might need going into a previously unknown repair or restoration if you can't find documentation of factory amount?

Also based on your experience, what are signs of too much oil and how to look for this condition? Just curious since I took the time to carefully determine the right amount.

Bud - Atlanta

 

[turbokinetic]

Hi Bud. That's a tough question. The GE Monitor Top fridges generally have a huge amount of oil in them.  There was still pressure in this system and no signs of large oil leaks. So I didn't see a need to add oil.

As for other systems, the GE Combination has a manual which shows the total oil charge. The systems with flooded evaporators such as the Philco, GE Flat-Top, and others with the evaporator that has a header built into it - those have to carry an extra large oil charge and the compressors were designed to operate with a widely variable oil level in the compressor. This is because widely variable amounts of oil are trapped in the system at any given time.

This is why retrofitting a modern compressor to these is very tricky. These compressors come with a minimum of oil in them and depend on it returning as fast as it leaves. They fail when the system collects oil in the evaporator.

As for knowing how much is too much - if the oil level gets up to the rotating parts of the compressor or motor, it would cause a huge amount of drag. The motor would overheat for sure. My uncle's friend told me this story. Somebody heard the compressor making a rattle and assumed it was low on oil. They bought one or two automotive oil charge cans (back when they sold R12 for $0.75 per can) and put it in the system. This caused the compressor to draw about 75% more power than it was supposed to. It also ran fire-hot and tripped the overload after 10 or 15 minutes.  I don't know how much oil is in those cans or what grade it is. But it was too much and the compressor got really hot.

I know most older compressors are designed for a large oil charge. The GE Combination wall mount had if I remember 800CC (about one quart) listed oil charge. I added an extra 4 ounces of oil to it since I had replaced the condenser coil, dryer, and blown a bunch of oil out of the rest of the system.  That was an "educated WAG" if you know what that means.

Manufacturer's literature is the best way to know the original oil charge but even that is not always easy to interpret. Cutting open old compressors and looking for telltale signs of where the oil level was, or studying the design and seeing what the highest level that would not cause problems would be, has been valuable as well.

 

[supersuds]

The videos seem to have disappeared already. Was there a problem?

 

[turbokinetic]

I have had to make the videos private for the time being due to YouTube issues. The DR1 is still working fine.

 

[bradfordwhite]

 

I like the monitor top design.  These were so efficient and quiet.  The modular ones were such a good idea as well.  Easy to service if there is a problem with the compressor, just remove the top and install a new one.  

 

I would think  one could even take a modular top, get a newer well insulated vertical freezer or all frig. that has a bad compressor, cut a hole in the top, and set the monitor top on and have a "new" monitor top that's bigger and well insulated. 

 

[turbokinetic]

Hi Keith!  The Monitor Top design was very good, for serviceability as well as efficiency. I like your idea of using a MT cooling unit on a modern cabinet as a replacement cooling unit!  That would be interesting to see for sure.

Interestingly, many other manufacturers had unitized, removable cooling systems which attached to the top of cabinets. Westinghouse had one which could slide out to the front, with a round wood post containing the lines and passing through the cabinet top.  The top had a compartment concealing the unit, so it didn't look like a GE. But there was some shared ideology.

 

 

[toploader55]

" Removable Monitor Top "

I think it was back in the late 70s or 80s...

Traulsen Refrigeration or maybe Manotowoc had commercial Reach In Refrigerators with a modular Condenser / Evaporator design that if it failed, a tech could move the unit and drop another in place while the failed unit was repaired. I liked the idea but as long as I can remember it never took off.

David, as always your videos are just amazing. You truly are a wizard when it comes to restorations and the presentations are just brilliant. Thank you for your efforts in repairing these Mechanical Marvels.

 

[bradfordwhite]

Probably the most modern example of a monitor top would be the ice freezers where they sell block ice.
These look like the compressor on top is removable.

It would be tremendously easier to recycle old frigs if the compressor system were modular and more efficient with it on top.

 

[turbokinetic]

Eddie - thanks for the compliment on my repairs. I am not that good - I just learn fast and manage to catch mistakes before they become bad LOL! 

 

Yeah I noticed how the commercial machines are similar to how the antiques were. They sell cheap shit to the homeowner but the commercial guy can still buy a quality product meant to be serviced. 

 

Keith, you got me thinking now - will have to look at the next ice merchandiser and see how the evaporator is done inside! 

 

[toploader55]

Just got me thinking about the Commercial end of refrigeration...

I was just at Hoshzaki's website. The Condensers are either up top pr the bottom depending on the model.

Here is a link to a top Condenser / Evaporator up top. Click on the pics to get the "slide show". Great idea about having a washable filter for the condenser to keep it clean from dust and grease.

Now the biggest challenge of all... is getting your employees to wash that filter every two weeks.

Hoshizaki R1A-HSL, Refrigerator, Single Section Upright, Half Stainless Doors with Lock

The R1A-HSL Steelheart Series upright single section refrigerator with half stainless doors is an attractive workhorse for any business.

hoshizakirefrigeration.com

 

[turbokinetic]

Follow-up...

Still working!