tedk Posted May 2, 2013 Share Posted May 2, 2013 A customer called today about a Crane National 797 I have at their location. THe pop has been warm for a few days. When I arrived and opened the machine, the compressor was running ( I think) but the fan behind the compressor was not. The fan in the refridgeration module was running. The temperature in the cabinet was 74 degrees. When I taped the door switch closed and pressed F1 the temperature had a dot behind it which indicates the compressor is running but the fan still wasn't. I spun the fan by hand and it started and the temperature started to drop. In the first 2hours the temperature dropped from 74 to 44. Over the next hour it fell to 38 or 39 degrees. An hour later it was 34 and an hour after that it was 32. I have now unplugged the machine for the evening. I am guessing the refridgerant level is ok but the fan and probably the thermostat are gone. Can anyone confirm this or suggest anything else??? Thanks, Ted Link to comment Share on other sites More sharing options...
moondog Posted May 2, 2013 Share Posted May 2, 2013 A customer called today about a Crane National 797 I have at their location. THe pop has been warm for a few days. When I arrived and opened the machine, the compressor was running ( I think) but the fan behind the compressor was not. The fan in the refridgeration module was running. The temperature in the cabinet was 74 degrees. When I taped the door switch closed and pressed F1 the temperature had a dot behind it which indicates the compressor is running but the fan still wasn't. I spun the fan by hand and it started and the temperature started to drop. In the first 2hours the temperature dropped from 74 to 44. Over the next hour it fell to 38 or 39 degrees. An hour later it was 34 and an hour after that it was 32. I have now unplugged the machine for the evening. I am guessing the refridgerant level is ok but the fan and probably the thermostat are gone. Can anyone confirm this or suggest anything else??? Thanks, Ted I can't see why you'd suspect the thermostat - sounds like you just need to replace the fan, if it kicked out once it'll do it again. I don't know where you're at, but National has a service supply center here in Ontario, Ca. and I'm sure they've got them elsewhere. This should be an easy fix. Link to comment Share on other sites More sharing options...
tedk Posted May 2, 2013 Author Share Posted May 2, 2013 Thanks Moondog. I am definitely replacing the fan. The reason I'm concerned about the thermostat is because the temperature has dropped to 32. The machine is supposed to be set at 38 and there should only be a couple of degree fluctuation plus or minus. Ted Link to comment Share on other sites More sharing options...
Walta Posted May 2, 2013 Share Posted May 2, 2013 a Link to comment Share on other sites More sharing options...
moondog Posted May 2, 2013 Share Posted May 2, 2013 Thanks Moondog. I am definitely replacing the fan. The reason I'm concerned about the thermostat is because the temperature has dropped to 32. The machine is supposed to be set at 38 and there should only be a couple of degree fluctuation plus or minus. Ted I get it now - Walt says that sodas won't freeze above 20 degrees and 25 degrees for diet sodas so unless your vending something else you should be okay. I'd replace the fan first and check the temperature again after it's had time to stabilize. Ps. Do you have that small relay board on the compressor unit - I've got a couple of 474's that do and it's apparently a weak link in the system or so the tech who refurbished one of my compressor decks told me. Link to comment Share on other sites More sharing options...
tedk Posted May 2, 2013 Author Share Posted May 2, 2013 a Walta, I didn't know you were Canadian Link to comment Share on other sites More sharing options...
Walta Posted May 2, 2013 Share Posted May 2, 2013 If nothing was hitting the fan I would replace the motor. I do not believe this machine has a thermostat. If it is the one I have in mind you have a temperature probe and a Relay/ triac to turn on and off the compressor. Let it get to 31 and look for the dot on the display. If the compressor is running and you have no dot the Relay/ triac may be shorted. Walta Link to comment Share on other sites More sharing options...
Walta Posted May 2, 2013 Share Posted May 2, 2013 I wanted to change my post after I posted it. The system would not let me leave the post as a blank. So that’s how you get an A from me. Walta Link to comment Share on other sites More sharing options...
tedk Posted May 2, 2013 Author Share Posted May 2, 2013 Walta: You are right, the machine does have a Triac. The place was getting ready to close the office so I left about 7:30 with the temperature at 39 degrees. It had been dropping about 1 degree every 20 minutes. One of the yard men checked it for me at 8:30, - 34 degrees and again at 9:30 as he was leaving and it was 32 degrees. I was afraid that if it didn't cycle off the pop would be frozen by tomorrow morning so I had him unplug it. I will have to start over tomorrow. Do you know if I will have to pull the refridgeration unit out to change the fan or can I get at it from the front or back of the machine? Thanks, Ted Link to comment Share on other sites More sharing options...
Walta Posted May 2, 2013 Share Posted May 2, 2013 I do not think you can get at the fan from the back it is just too tight and the fan blades may get bent and out of balance. Pulling that unit is a pain. Walta Link to comment Share on other sites More sharing options...
AZVendor Posted May 2, 2013 Share Posted May 2, 2013 The National 797 can and snack combo does have a small board underneath the can module that is called the Triac PCB. The triac on this board will cause the refrigeration to run non-stop if it fails and melts inside. You will have to replace it with a 35W Triac. The evaporator motor in the cabinet will run all the time to circulate cold air and prevent the evaporator from freezing. The condensor fan should only run when the compressor is running. You should not ever have to start it spinning by hand. You will need to replace the fan motor and probably the triac. These two problems are not likely to be interrelated as if they were, you would have already had frozen cans. I doubt the temperature probe is bad because it sounds like you had a room temp reported when cans weren't cold and then cold temps reported as the machine cooled down. To replace the cond. fan motor, you will have to empty all the cans either by free vending them or pulling the can module door off and removing the cans. To remove the door, pull out the candy shelf and removed the door retaining brackets right and left to release the door - it's gasket may be stuck. After the cans are out, you have to disconnect and label all harnesses from the bottom of the module including the Triac PCB and any other boards as well. Locate and remove any retaining brackets from the 4 legs of the module and from the top edges of the module. You should be able to walk or slide the module out of the machine onto a rolling dolly of some sort that can support the legs of the module. When it's out of the machine you can reach the cond. fan motor. Reinstall in reverse order and reconnect everything you labeled when beginning. After restarting the machine, let it run for a few hours and then see what the temp is before loading with cans. Link to comment Share on other sites More sharing options...
tedk Posted May 2, 2013 Author Share Posted May 2, 2013 Thanks Randy Link to comment Share on other sites More sharing options...
moondog Posted May 2, 2013 Share Posted May 2, 2013 The National 797 can and snack combo does have a small board underneath the can module that is called the Triac PCB. The triac on this board will cause the refrigeration to run non-stop if it fails and melts inside. You will have to replace it with a 35W Triac. The evaporator motor in the cabinet will run all the time to circulate cold air and prevent the evaporator from freezing. The condensor fan should only run when the compressor is running. You should not ever have to start it spinning by hand. You will need to replace the fan motor and probably the triac. These two problems are not likely to be interrelated as if they were, you would have already had frozen cans. I doubt the temperature probe is bad because it sounds like you had a room temp reported when cans weren't cold and then cold temps reported as the machine cooled down. To replace the cond. fan motor, you will have to empty all the cans either by free vending them or pulling the can module door off and removing the cans. To remove the door, pull out the candy shelf and removed the door retaining brackets right and left to release the door - it's gasket may be stuck. After the cans are out, you have to disconnect and label all harnesses from the bottom of the module including the Triac PCB and any other boards as well. Locate and remove any retaining brackets from the 4 legs of the module and from the top edges of the module. You should be able to walk or slide the module out of the machine onto a rolling dolly of some sort that can support the legs of the module. When it's out of the machine you can reach the cond. fan motor. Reinstall in reverse order and reconnect everything you labeled when beginning. After restarting the machine, let it run for a few hours and then see what the temp is before loading with cans. That set up sounds just like my 474's - is it the same Soda/compressor unit? I rebuilt one awhile back and had to replace some of the door ejectors - it does take some persuasion to get the gasket loose. I also replaced the relay/triac and had an A/C shop top off the refrigerant. The rest of the machine is basically a 147. I also replaced the price tags - weird design but they work. Link to comment Share on other sites More sharing options...
tedk Posted May 3, 2013 Author Share Posted May 3, 2013 Moondog, Walta and AZ, Thank you so much for all your help. Talk about a machine that is built for assembly not repairs, this is one. Took 10 to15 minutes to actually change the fan, but two hours unloading and taking the machine about and the same amount to re-load and re-assemble. AZ thanks for tellling me to label everything carefully. I even labelled all the brackets and screws, it helped a lot. Ted Link to comment Share on other sites More sharing options...
moondog Posted May 3, 2013 Share Posted May 3, 2013 Moondog, Walta and AZ, Thank you so much for all your help. Talk about a machine that is built for assembly not repairs, this is one. Took 10 to15 minutes to actually change the fan, but two hours unloading and taking the machine about and the same amount to re-load and re-assemble. AZ thanks for tellling me to label everything carefully. I even labelled all the brackets and screws, it helped a lot. Ted No Lie ! A normal soda machine compressor deck can be pulled in ten minutes - I got to where I could do one of these in an hour (I only did it about six times before I got it right) Link to comment Share on other sites More sharing options...
tedk Posted May 3, 2013 Author Share Posted May 3, 2013 Six times! If I never do it again I'll be ok with that. Link to comment Share on other sites More sharing options...
Repairman Posted May 5, 2013 Share Posted May 5, 2013 I have had to replace that fan before. It is a job. One of the reasons I dislike combo machines of this type. I would not do it on location if it could be helped. Link to comment Share on other sites More sharing options...
moondog Posted May 5, 2013 Share Posted May 5, 2013 Six times! If I never do it again I'll be ok with that. I had it in my shop fortunately - this was one I picked up for $200. I thought I was getting a great deal but in the end that was probably a fair price. If I ever did this again, I'd swap out that relay/triac first thing - the rest of it was pretty straightforward. Even the ejectors weren't that bad once I got the gasket loose. Link to comment Share on other sites More sharing options...
tedk Posted May 6, 2013 Author Share Posted May 6, 2013 I was lucky that the machine has a lot of room around it for me to work even though the don't have the room for two machines. The employees gave me lots of space and pitched in when I needed a lift too. I can't imagine how hard it would be to do this in any of my other accounts. Link to comment Share on other sites More sharing options...
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