Ice build up freezer

[PMARS2345]

What causes ice to build up around the hole on a evaporator where the fan blades are, to the point where blades are scraping ice? Electric defrost, clear drain and clear coil. Called Señor tech and he stated defrost termination was going too long then he thought maybe it was too short. Any idea would be great, have 2 locations with this problem and I'm flipping a coin on which way I adjust defrost termination settings. Maybe that's not even the issue. Any input would be greatly appreciated.

[fengshvac]

What causes ice to build up around the hole on a evaporator where the fan blades are, to the point where blades are scraping ice? Electric defrost, clear drain and clear coil. Called Señor tech and he stated defrost termination was going too long then he thought maybe it was too short. Any idea would be great, have 2 locations with this problem and I'm flipping a coin on which way I adjust defrost termination settings. Maybe that's not even the issue. Any input would be greatly appreciated.

hahaha, this is so simple.. muhahhahaha

[ryan1088]

Well you haven't really given us much to work with here. Have you checked the heaters? Box infiltration? Stock room door guy have the door open all day? Timer initiating defrost? Is it stuck?

[Tommy knocker]

hahaha, this is so simple.. muhahhahaha

Really? So what is it oh enlightened one? Teach us.

[craig1]

It is often caused by no fan delay. Now you have to figure out why there's no delay.

Obviously a bad termination/fan delay switch would do that, but there's other causes possible. if the clock is terminating defrost before the termination switch, the fans will start immediately. Causes for this could be be the defrost limit time set too short, heaters not working right, or excessive frost load.

[Tommy knocker]

Is there also ice on the ceiling in front of the evap fans?

[Tommy knocker]

It is often caused by no fan delay. Now you have to figure out why there's no delay.

Obviously a bad termination/fan delay switch would do that, but there's other causes possible. if the clock is terminating defrost before the termination switch, the fans will start immediately. Causes for this could be be the defrost limit time set too short, heaters not working right, or excessive frost load.

Yep

[EugeneTheJeep]

I have seen it happen when the DFT was failed, and the cycle was ended only by the default 40 minutes, replaced a DFT a couple of months ago and problem solved. This can also cause icing on the ceiling, the higher temps cause the water to vaporize during defrost.

[2sac]

Check the above mentioned defrost termination issues as well as air infiltration thru the door, box seams, pipe chases, untrapped drain, conduit, etc.

[primmers]

i just changed a fan delay for this same thing.

[icemeister]

I'd rule out any infiltration issues first. Since the coil is clear and ice is building up around the fans, this points to moisture infiltration in my book.

In my experience, employees and/or vendors leaving the door open for long periods (or not fully closing it) will cause this problem. Positive door closing mechanisms and a door switch to kill the fans usually resolve it. Trying to educate them never does.

[Kool Tech]

It is often caused by no fan delay. Now you have to figure out why there's no delay.

Obviously a bad termination/fan delay switch would do that, but there's other causes possible. if the clock is terminating defrost before the termination switch, the fans will start immediately. Causes for this could be be the defrost limit time set too short, heaters not working right, or excessive frost load.

I agree with this Craig1 said. Also one more thing to check would be is it the right fan & blade installed? It may be improper air flow, or dirty coil in this area, check back side of coil.

[EugeneTheJeep]

Infiltration and door open usually freezes the coldest part in the box first, the coil, fans wont frost up with no air flow through the coil, frost around the fans means humid air went through the colder coil, or the length of defrost caused vaporization and the vapor went to the next coldest spot near the coil and condensed there?