Walk-in Freezer problem

[Gary]

Although the OP said the liquid line was frosted, none of the other numbers indicate a liquid restriction. If there is a restriction, it is minor.

[airefresco]

Regarding the liquid line freezing - It was frozen inside the evaporator, like Nike said. It was at ambient temperature at the condenser end.

[fridgability]

Something else to watch out for on single phase units with two or more evaporator fan motors, if a motor is faulty or has a faulty capacitor it can run backwards. Initally it does not start but the one or more good ones draw the air backwards over the fan blade and it eventually starts and runs backwards thus cancelling out the air flow of the good motors. The effect is no air flow over the evap with most of the symptoms described. Get someone to switch the unit on while you watch the fan motors start. Good luck.

[Peter_1]

Hey, that's a good one to remember.

[airefresco]

Yeah I have that before and always look out for that now. It must catch a lot of people out as when you look at the fan it looks like it is running and when they pick up a bit of speed, it´s difficult to tell which way they are going.

[Gary]

Yeah I have that before and always look out for that now. It must catch a lot of people out as when you look at the fan it looks like it is running and when they pick up a bit of speed, it´s difficult to tell which way they are going.

This tends to give you a very high evap dT.

[mad fridgie]

The unit is tired, suggest the discharge temp has been very hot, witch has given wear on the valves/rings (not totally rooted), this would give poor performance and also give the smell in the refrigerant,
If the comp is a danfoss, then there could be slight passing under the head (Danfoss have 2 steel bands to hold the internals of the compressor together (in stead of bolts) very difficult to diagnose the fault)

[airefresco]

I like that theory a lot as explains almost everything. Except that it is working fine now and has been for a couple of weeks, so if that was the case would the performance always be poor or would it be more of an intermittent thing?

[mad fridgie]

I like that theory a lot as explains almost everything. Except that it is working fine now and has been for a couple of weeks, so if that was the case would the performance always be poor or would it be more of an intermittent thing?

The ambient would of dropped a couple of degrees lately, so load is slightly reduced, actual discharge pressure would of reduced, net cooling would of increased slight due to this fact, giving the impression all is well (temp is meet) Run time would still be a bit longer than, if this scenerio was not there. If for example the system was down 20% in capacity, then it would struggle, in your hottest periods (which seems to be the case). I suggest you will have a similar problem next summer (getting worse over time)