Gram K400

Hello guys, i'm having an annoying problem with a gram upright fridge.
A few months ago I changed the evaporator due to stupid staff defrosting with a sharp knife(2nd time, on this site),fridge put back into service ran fine for a few weeks but every now and then would stop cooling and temp would go up(usually overnight). I went to look at it a couple times, and couldn't really find anything wrong. I ended up changing the pcb, and again it ran fine for a few days, and then it started playing up again.
When I changed the evap, I weighed the gas in, today I put a clamp meter on the comp and found it to be running about 0.25a over its stated flc of 0.81a. So it looks like I've overcharged it and is possibly going out on internal overload - anyone agree?
I've taken some of the gas out and got the running current down a bit (0.86amps ish) but the suction pressure/temp looks wrong 0.5 bar / -16deg C.
I'll have to see how it goes, has anybody got any other ideas?
Something else I have noticed on the fridges is that the temp display/probe are very slow and lazy to respond, Is it just me or are they all like this?

Andy

What refrigerant is it charged with, Ive only come across k400 with r404a charge.

I would say that it is the comp cutting out.
They were really bad for that.

Make sure to clean the cond fan grill. (4 screws to remove it and clean it properly)

Also, push the cabinet up against the wall as this helps a lot.
And yes, they are really slow because the probe is on the door.

Chillin:):)

Sorry guys, its a compact k400 upright, R134a, no condenser fan, probe behind evap. Looks like a domestic fridge on wheels! has one button conroller.

Andy

Is it the one where you have to push the button really hard to change the temp?

There is 2 probes on this case?
One is the cut out and the other is the cut in.
Could still be the comp goosed though.

Chillin:):)

Definitely only one probe.
Push button once to get set point(flashing), keep pressing to scroll through to desired temp.
Danfoss TL5F compressor - usually pretty reliable.

Moisture ?

Hi Andy

As with all Gram electronics the display temperature is the set point and is not a live indication of the chamber temp.

The controller on this particular cabinet is a Danfoss ETC type which has display delays, minimum stop and run compressor times etc. If you would like the Danfoss technical manual on the logic please send me a PM.

As for the loss of refrigeration the compressor is indeed protected by an internal thermal protection which once triggered will take some time to reset. Usually this is an effect and the cause could be high ambient, excessive evaporator load or lack of suction cooling from incorrect gas charge or a system restriction.

I guess you can never rule out that the internal thermal protection may be faulty.

It is also not uncommon for the compressor to require replacement after the evaporator has become punctered because of the ingress of air and moisture and the length of time the cabinet may be left runnung without any gas before someone decides to switch it off.

What are you measuring the compressor body temperature at? The design condensing temp is +55oC.

Hope this helps,

Sturt

Poxy thing gone down again today:(, will get it back to workshop next week to give it a drier change, bloody good vac and recharge and long run/test.

Andy

we had problems with gram freezer customer always complaining it wouldnt get to temp anytime i was there it would eevn took it off site and it worked perfectly.... ithink it is there to test me lol

had the same on a sadia years ago, that was moisture.

done alot of work on k400 new compact range and have found the reliability of the controller to be very poor. I would recommend trying a new controller with probe and moving sensor better into airflow closer to baffle. Hope this works.

fridge aahhhhhhhhhhh!!!!!1

:rolleyes:when they punctured evaporator, they were scraping off ice/moisture. when gas run out and pot run in vac:o

guess the rest:off topic:

Id say moisture in the system, the numb nuts prob left cabinet running for hours after they stuck the knife in it! Comp is then prob cutting out on internal overload due to the resistriction the moisture is causing.

hi andy
ur problem cleaning system from water u have to seperate evaporator condenser make a shreider from one side &u blow out all water moisture with liquid refrigerant change compressor oil &good luck its a hard job

Thanks for all the input guys, unfortunately I haven't been able to go and get the fridge, as the ownership of the restaurant/bar has changed hands and has been shut for the last couple of months.

Andy

I had a situation like this long ago. I took a contract with a chain of chinese restaurants, and foolishly believing that if I did the job right then I could warranty my work, unconditionally.

the issue was with an ice machine, tiny thing, made by Scotsman, under the counter unit, that would run for a while, and then every now and then, when they arrived in the morning, no ice.

I returned to this location 27 times.

I told myself that this was valuable chance to teach myself on the job. I deluded myself into thinking that I would eventually make money, once I learned what I was missing.
I cleaned, vacuumed, recharged, tested, checked etc this thing countless times. I bought charging cylinder, weigh scale, the best temp tester i could find, temperature recorder, etc. I bought every manual and book you could find on ice machines, and I read them cover to cover. I replaced the filter drier at least 3 times. I sat there on the floor in front of this thing from morning until night, at least 3 days in a row. It never failed one time while I was watching it. I would step out for a coffee and a leak, come back and it would be running but ice would be melting. I would show up in the morning and it would be running but full of melting ice/water.

Finally, there was a young chinese guy, working his way through university, who waited tables there. He asked me a bunch of questions about what was happening, and i told him I didnt know. he watched this craziness, for 2 days, and finally came to me and told me that the staff and manager were screwing me around. they would shut it off when i would leave, and turn it/the breaker back on when I would return.

I dropped the chain. the owner called me for 3 years asking me to come back and service his equipment, but of course wasnt interested in paying for the full bill for the ice machine.

I told him to get stuffed.

Quote:

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Originally Posted by Andy AC

Hello guys, i'm having an annoying problem with a gram upright fridge.
A few months ago I changed the evaporator due to stupid staff defrosting with a sharp knife(2nd time, on this site),fridge put back into service ran fine for a few weeks but every now and then would stop cooling and temp would go up(usually overnight). I went to look at it a couple times, and couldn't really find anything wrong. I ended up changing the pcb, and again it ran fine for a few days, and then it started playing up again.
When I changed the evap, I weighed the gas in, today I put a clamp meter on the comp and found it to be running about 0.25a over its stated flc of 0.81a. So it looks like I've overcharged it and is possibly going out on internal overload - anyone agree?
I've taken some of the gas out and got the running current down a bit (0.86amps ish) but the suction pressure/temp looks wrong 0.5 bar / -16deg C.
I'll have to see how it goes, has anybody got any other ideas?
Something else I have noticed on the fridges is that the temp display/probe are very slow and lazy to respond, Is it just me or are they all like this?

Andy

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Hi
Guys , I have two years old gram k 400 fridge which evoborator was knifed by kitchen porter and called engineer who came and tried to seal leakage , but he made more big hole and said it is evoborator has to be changed. Called gram dealers and given price 200 for parts and 150 for labour.
What do I need to do ? Can any body give me some advice
My number 07776146269 call any time

You better give them a call then, there is nothing you can do yourself, apart from beat the kitchen porter repeatedly.

Andy