I have a model 9301a cooling unit that generates a LOT more condensate than it dissipates and runs onto the floor. What could be the cause of this problem and/or how can I solve it?

[fixbear]

First off, is the unit level?

 

Is the drain open to the compressor compartment?

 

Is the drain pan intact and does the compressor discharge line go through it and fastened to the pan or has it been modified and not in the condensate?

 

Are the door gaskets intact and sealing?

 

Are the doors kept close as much as possible?

 

Is room ambient temp below 95F?

 

There is not much room in the condenser compartment of that model. And axial fans do not make any wash like a plain fan.  Let alone that they are angled upward.  You could add a condensate pan and heater underneath if all else fails.Birmingham, Fisher, Kason, and Supco all have them.  They make them from 30 oz to 15 quarts evaporation rates from 4 oz per hour to 12 gallons per day

 

They also make felt pads that are placed into the condensate pan with a stainless spring to keep them vertical so that air can move over them.

[olivero]

I always wondered if a unit on low refrigerant could cause this.

 

But I would think the discharge temp would go higher as the refrigerant level goes lower due to a leak or whatever, in which case it would evaporate more water.

 

It’s one of those thoughts I get when I see a full pan like that.

[ectofix]

Actually…no, the discharge temp would go lower too.

 

Less refrigerant = less refrigerant in the space that it occupies.  The space didn’t change.

 

TRULY, the only situation where you should expect a HIGHER discharge pressure than normal is when the high side is less capable of dissipating heat.  Such as when the condenser coils are clogged with grease, fuzz  and whatever.  It’s the heat CONTENT in the refrigerant that causes a higher discharge pressure. 

I’ve seen arguments over this. 

 

The affects of systems still having a full charge but showing a low SUCTION pressure, but a HIGHER than normal discharge pressure is generally caused by someone unnecessarily ADDING refrigerant as a mis-diagnosis.  Essentially, they did so because they THOUGHT a system was low on charge, but did not admit that they added some “freon”.

 

WHY do I think that?

Well, again…it’s the heat content within the refrigerant that affects its pressures – IN A FULLY CHARGED SYSTEM. 

Charles’s Law – which describes how gases tend to expand when heated.

 

So, the less heat absorbed on the low side would translate to less heat content on the HIGH side.  Therefore…

A system with a restricted refrigerant flow into the low side (clogged capillary or failed TXV) would cause less heat to be absorbed by it and, therefore, a lower discharge pressure due to the reduced heat content. YET…a system that’s low on charge will ALSO have lower pressures across the board.

 

That’s where the confusion lies between those two scenarios:

Is it LOW ON CHARGE, or… IS THERE A RESTRICTION of refrigerant flow at the expansion device.

 

Mull over that for a little bit…as we wait for fixbear to interject his wisdom over the topic.

[fixbear]

I always wondered if a unit on low refrigerant could cause this.

 

But I would think the discharge temp would go higher as the refrigerant level goes lower due to a leak or whatever, in which case it would evaporate more water.

Ectofix is correct on what happens.  But also remember as the refrigerant goes under charge,  the compressor load will drop.  Including amps. Years ago before accurate scales were used we charged by load on a cap system. Also as the refrigerant drops the evaporator coil will not saturate. You will only have a bit of the coil freezing near the in line.  Just like under metering. Compressor discharge temp will also drop drastically from lack of load.

 

As for increase water, only if the coil was froze up. The lack of cooling power allows the coil to warm up and defrost.  And if the evaporation system is a hot gas or crankcase oil pipe, No evaporation happens.  On this particular machine, the condensing fans are muffin and angled at a up angle.  Not going across the condensate pan.  Normal condenser fans have a lot of radia wash that isn’t going through the condenser. Makes a great way to evaporate water. Just add a form of wicking.

 

Having excess condensate water is most commonly from High humidity, leaking gaskets, or overuse.  Also open containers inside the box.   And the worst, trying to cool hot pans of liquid in a reach in. They just are not made for it.  Walk ins only for that.  And they should be designed with less than 15 degree take down.  High take down units will freeze up the coil quicker.  And remove more moisture.  Floral coolers have just a 5 degree take down to keep from drying out the flowers.

[olivero]

Okay,  I get what your saying Ectofix and Fixbear,

 

But also take into account that the compressor will most likely overheat as the refrigerant level drops, that will also boost the dishcharge temp as there won’t be much cooling on the compressor if the refrigerant is low.

 

What you mentioned about the discharge temp being proportional to load is also logical, I didn’t think of it like that, but I wonder if just not having enough cooling in the compressor can boost that.

 

But I guess not by much.

 

I kind of jacked this tread I think…

[olivero]

“ The lack of cooling power allows the coil to warm up and defrost”

 

I am not sure if that’s true.

 

If you went way down in refrigerant level, like it sprung a pinhole and dumped its charge, then yes.

 

If it’s a slow leaker, as that suction pressure goes down, the colder the refrigerant will get and constantly freezes up the coil, rarely does the refrigerant drop so low (prior to getting fixed) that there is nothing on the coil. At least in my somewhat limited experience.

[fixbear]

Not true. with a slow leak, the evaporator will not reach design temp across the whole unit.  How ever the inlet coils will flash the refrigerant to gas quickly in the first 1/4 to 1/3 of the coil. Making ice form in that area, but not have the capacity to cool the unit or satisfy the temp control.  That is why Suction pressure control is proffered on walk in’s.  They also use accumulators to relieve the accuracy of the charge. When low they short cycle.  If using medium or low temp compressors they use a bypass on the TXV to limit the load on the compressor when the box is to warm.  Meaning that they sense the tail coil for metering normally, but also sense the suction pressure to prevent overload.  Before bypass valves there were many compressors that got liquid flooded and destroyed when adjusting super-heat.  I destroyed a 12 HP Bristol once that way with the wrong charge replacement that the wholesaler said would work OK.  Part of my early years with a dehumidification kiln.  And trust me, they will make you think and throw a lot of normal’s out the window.

[fixbear]

olivero wrote:

 

 

But also take into account that the compressor will most likely overheat as the refrigerant level drops, that will also boost the dishcharge temp as there won’t be much cooling on the compressor if the refrigerant is low.

 

The compressor will not over heat till there is no gas to move. Due to the lower amperage and still having some cooling it will actually only be marginally warmer. Never as hot as a non starter or totally out.  Discharge line will have minimal heat if out of gas. Full load discharge will be hot enough to burn you. Often 50 degrees above head temp. I have seen 300F on a R12 system.  But again, that was a specialized piece of equipment. with 145 degree condenser air.

[olivero]

Right, you won’t be able to reach set point as your effeciency and heat pick up is so little that you are not really removing any heat. Nor will the coil every defrost as the ice will keep spreading UNLESS it dumped everything and there is simply no charge left to flash.

 

My point in it is that the compressor will get hotter and hotter from a lack of cooling from the refrigerant circulating. As the charge goes down, the superheat goes up and naturally, the compressor will be cooled less and less, giving higher and higher discharge temps.

[olivero]

Hmm, I don’t quite think that’s the case.

 

I’ve seen comps go out on high temp safeties before due to low refrigerant level, here in Florida, the residential comps get a run for their money.

 

I guess what you are saying kind of does make sense though, I don’t know for sure, I think if there is no gas, then obviously the comp will kill itself in no time as its also pumping whatever its sucking in through the leak.

 

Maybe I’m wrong, I’m okay with that, lol.