walk in freezer ice

[theharleyman]

I have a walk in freezeer which is maintaining 0 degrees, but they called and said there was a 3' icicle. I get there and noticed this icicle hanging off the bottom of the suction line trap where the insulation was tore. I also noticed a lot of ice all over the boxes underneath the evap. and also half the evap had about 5 inches of ice on the back of it. It has 4 fans, all of which were working. I checked the drain line, not clogged. I checked the heat tape on the drain line inside the armaflex, it was working. Checked the defrost cycle and heaters, they work. After getting the ice off I did notice the fins on the evap side that was iced up were bent over quite a bit which would obviously affect air flow. Could this have been the only problem?

[starscream22]

Was the defrost clock moving? Maybe it is stuck.

[theharleyman]

yes, the time clock is OK. It seemed like the ice I melted off was on the back outside of the evap coil, not any in the coil itself.

[leathernecke5]

Check the temp drop accross the coil. Then check the subcooling to make sure you have enough ref in the system. Not just by the sight glass.

[stenfam]

how many defrost heaters are in this?
Any terminatin klixons?
What amps do you pull on each Heater circuit?
how about the possibility of high humidity / ambient?
Have the doors benn open a considerabl amount of time?
Alot of warmer than FROZEN product been introduced?
if all defrost heaters are working, hown many cycles and for how long?


I have a TYLER Pressure Temp. chart, which also tells the reccomended amounts of time for this, and alot of times you can find someting CLOSE to what you are working on to get you in the ballpark..

dan

[condenseddave]

Back up. Slow down. Hold the phone, and for Pete's sake, put away all the test equipment and charts!

Fix the drip that is causing this.

You're at a zero box. That's plenty cold. It'also means that the suction line with the torn insulation is at about -15.

If the armaflex is torn, as you describe, you're simply forming that little icicle from the condensation on the suction during each defrost.

Jesus, SUBCOOLING?????? Temperature drop??????? Defrost clock????????? for a 3 inch icicle???????????? In a walkin freezer with torn armaflex???

I'll have whatever he's having. LOL.

[condenseddave]

Maybe you should run a mass flow calc on the system, just to be sure.

[leathernecke5]

I have had a couple of walk-In freezers that would work ok most of the time temp wise but after awhile ice build up on evaporator(near TXV and spreading). Winter time not to much problem, sight glass full. Then I happen to check my subcooling after I did it the old school way of blocking the condenser and added Ref to get sub cooling near the 15 degrees and my ice buildup was curtailed considerably. I figured a little low on gas in summer time affected pressure drop in evaporator. In the winter or low ambient conditions though not that prevelant no humidity etc.

[stenfam]

3 FOOT if I read correctly.
I know.. I was thinking out loud as I typed!
O.k., Maybe I thought about a FEW things, but Ya know... they all SHOULD be thoght about..

by the way.. it was strohs last night

[keywest]

ive had this problem before make sure that when the system gose into defrost that the fans shut off

[jaybird396]

Check to make sure your defrost klixon is not turning on evap fans right after defrost. They should not come on until evap temp has come down to avoid blowing water vapor from defrost everywhere.

[ace mechanic]

Just check the pitch on your drain pan. Watch the system on defrost and see where all that water is coming from.

[stat]

Was it the bottom of the evap that was covered in ice? Was the drain pan full of ice? If it was, check the pan heater. Does the suction line go straight up through the top of the box? If it does, could be condensation running down the suction line from above.