commercial walk in freezer qestion

[cborel]

walkin has ten fans . compressor in separate room. Should fans push or pull the air? no one seems to be sure.

[Brian_UK]

They generally pull the air as it reduces the jetting affect on the coil face.

Also the cowling around the fan blade encourages the air to be 'thrown' further.

[powell]

Are you asking because your fans are pushing?

About 16 or more years ago Witt redesigned their low profile unit coolers to push the air. The fan motors were on the back and the coil was in the front.

The theory was that the cabinet would act as a pressurized plenum and the air would distribute evenly and efficiently and have a longer air throw.

The problem was; some were installed backwards due to misunderstandings of the design and if a filter sock wasn't installed on the fan motor guards the coil would clog up and they were a PIA to clean.

Witt eventually converted back to the pull thru design.

[fridgemandan]

most systems that i work on pull the air across the coil, what type of evaporator is it?

[Toosh]

walkin has ten fans . compressor in separate room. Should fans push or pull the air? no one seems to be sure.

Hi Many years ago the fans used to push air through now the protocol has changed to draw through

[cborel]

It is a Russell evaporator. The coils are positioned behind slightly above the fans. The coils appear slightly cleaner in the set of fans that are pulling the air from the freezer up through the coil area..obviously i know little about this. But also the question needs to be answered as to whether all fans should go the same direction..

[chemi-cool]

It doesn't matter, its the design of the evaporator.

In some they pull the air and some they push.

[cborel]

Also, while I have your intelligence working for me...can you replumb the defrosting copper lines with another product..meaning the plastic used today.

[Monty1987]

hey mate, as far as i know but then i might be wrong or right this is what i think though. normally most of the coil fans suck air from alliminium fins side and distributes air from the fan side, it all depends what type of the evapoutor you dealing with. best way to check is the direction of the fan blade and which way its blowing. so then the evap should be sucking and blowing through the fans, and all fans should be going in one way.

[mad fridgie]

Tech terms
Forced Draft (blow)= Air In - Fan - Coil- Air Out
Induced Draft (suck) Air In - Coil - Fan - Air Out.
Both are acceptable, Induced draft, normally gives greater "air throw in free air" blows further.
When working with multiple fans all should be moving air in the same direction.
Yes can run drains in plastic, but if you need a heat tape, make sure plastic is high temp rated or the heat tape is temperature limited

[cborel]

Thank you very much ...the last post was extremely helpful...

[cborel]

new problem...now the fans are corrected but they run continuously even in the defrost cycle...what has caused this...