# Walk in cooler..



## user4818 (Jan 15, 2009)

That's typical. Nothing unusual about that at all. I know they run constantly in supermarkets. The fans are wired directly to a breaker with no controller whatsoever. 

The refrigeration is controlled separately of course.


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## BBQ (Nov 16, 2010)

Coolers will run the fan 24/7, freezers will often stop the fan during defrost cycles.

Sometimes the fans are wired to a door switch and shutdown when the door is opened.


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## B4T (Feb 10, 2009)

I just have to wire in a SP time clock on blower circuit for defrosting..


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## user4818 (Jan 15, 2009)

BBQ said:


> freezers will often stop the fan during defrost cycles.


Good point. I forgot about that. It's been a while.


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## backstay (Feb 3, 2011)

No, I did one last year. The first AC guy had me connect it to temp. The system didn't work right and they hired a differant AC company. I had to go back and wire the evap coils to a switch for servicing only. They run 24/7. The fans have to run during defrost, which is just a timer to cut out the compressor(it really runs a sol valve and the compressor runs on pressure).


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## B4T (Feb 10, 2009)

backstay said:


> No, I did one last year. The first AC guy had me connect it to temp. The system didn't work right and they hired a differant AC company. I had to go back and wire the evap coils to a switch for servicing only. They run 24/7. The fans have to run during defrost, which is just a timer to cut out the compressor(it really runs a sol valve and the compressor runs on pressure).


Now this is different from what I was told.. he wants TC on blowers.. :blink:


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## BBQ (Nov 16, 2010)

backstay said:


> The fans have to run during defrost,


It really depends on the unit.

If it is 'off time' defrost fans will likely be left on. If it is electric or hot gas defrost the fans will shutdown or the product in the cooler will get heated.


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## BBQ (Nov 16, 2010)

B4T said:


> Now this is different from what I was told.. he wants TC on blowers.. :blink:


Listen to the refrigeration contractor.


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## user4818 (Jan 15, 2009)

B4T said:


> Now this is different from what I was told.. he wants TC on blowers.. :blink:


Yeah, that doesn't make sense. I don't work on this stuff very often, but I'm positive the clock is to shut down the refrigeration side, not the fans. But, I could be wrong. Wait...did I just admit I could be wrong? :laughing::laughing:


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## BBQ (Nov 16, 2010)

Peter D said:


> Yeah, that doesn't make sense. I don't work on this stuff very often, but I'm positive the clock is to shut down the refrigeration side, not the fans. But, I could be wrong. Wait...did I just admit I could be wrong? :laughing::laughing:


My guess is there will be more to it than what B4T has been told yet.

It is usually bad to shut the fans off without killing the cooling at the same time.


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## B4T (Feb 10, 2009)

BBQ said:


> Listen to the refrigeration contractor.


My thoughts exactly.. if I wire it differently.. then it becomes my mistake.. :no:


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## backstay (Feb 3, 2011)

Just pulled the print out to double check, The temp control on this one runs a sol valve and the two evap fans have no control. It is not a hot gas defrost. It is a walk-in cooler. Just double check with the refrigeration contractor and if he's wrong you will have to rewire later. Look at it from the stand point of, if I have to change this how can I make it easier for me.


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## B4T (Feb 10, 2009)

BBQ said:


> My guess is there will be more to it than what B4T has been told yet.
> 
> It is usually bad to shut the fans off without killing the cooling at the same time.


Somewhere the thermostat has to be figured into the circuit to keep the compressor from starting.. just not sure where yet


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## Shockdoc (Mar 4, 2010)

Blowers run continuos, tsat controls soleniod valve inside cooler, pressure switch activates compressor.


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## B4T (Feb 10, 2009)

Shockdoc said:


> Blowers run continuos, tsat controls soleniod valve inside cooler, pressure switch activates compressor.


TC shuts off blower for de-icing.. what keeps compressor from starting up??:blink:


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## user4818 (Jan 15, 2009)

B4T said:


> TC shuts off blower for de-icing.. what keeps compressor from starting up??:blink:


In the walk in units I have done, the time clock shuts off the compressor circuit. It's just simple off time defrosting. 

I also did all the refrigeration wiring for a Walgreens store, and they used electric heat defrosting for the freezer and off time for the cooler. The refrigeration unit on the roof was prefabbed and had all the time clocks in it, I had to hook up all the field wiring.

That said, it's been quite a while since I last worked on any refrigeration stuff, and my memory of it all is quite rusty now. This thread is making me aware that I've forgotten how I've done things in the past. :blink:


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## Shockdoc (Mar 4, 2010)

B4T said:


> TC shuts off blower for de-icing.. what keeps compressor from starting up??:blink:


A pressure switch remotely wired on compressor. Soleniod valve in cooler closes in off position. compressor builds pressure, switch turns off. Soleniod opens, pressue in line drops and remote pressure switch closes and compressor starts. Tsat and solenoid should be wired load side of evaporator fan switch.


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## Norcal (Mar 22, 2007)

Make sure you seal conduits running between cooler & outside of the cooler.. Something I learned the hard way.:whistling2:


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## Abcanfield (Jan 15, 2011)

Norcal said:


> Make sure you seal conduits running between cooler & outside of the cooler.. Something I learned the hard way.:whistling2:


Are you referring to a conduit seal off? If so, where in the run is it installed?


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## mgraw (Jan 14, 2011)

Shockdoc said:


> A pressure switch remotely wired on compressor. Soleniod valve in cooler closes in off position. compressor builds pressure, switch turns off. Soleniod opens, pressue in line drops and remote pressure switch closes and compressor starts. Tsat and solenoid should be wired load side of evaporator fan switch.


 Don't you mean pressure *decreases on the low side* and the unit kicks off on the low pressue control.

There are many ways these units can be wired. Some units have door switches that shut off the fans and solenoid valve when the entrance door is opened. Some have a switch mounted to the fan unit that may or may not be connected to a solenoid valve. Some fan units receive power from the condensing unit. Some fan units get power from a TC.
Check with the refrigeration guy.


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## Wingman2002 (Jan 2, 2011)

We just wired a 50'X70' cooler that is split in to three separate sections. How it is wired depends on what the temperature settings inside the cooler will be. On ours the compressors were three phase and the evaporators were 120 volt. The evaporators run 24/7 on a separate single pole breaker. From the compressors we had to run two wires inside each section to a 120 volt line side temperature sensor. They got power off one leg of the three phase power in the compressors.


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## Jlarson (Jun 28, 2009)

Just listen to the AC guy. He knows (or at least he should) how that model of cooler works exactly, we don't. 



Abcanfield said:


> Are you referring to a conduit seal off? If so, where in the run is it installed?


You need to seal the conduits somehow to prevent air movement between the cold and warm areas and in turn condensation.


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## Shockdoc (Mar 4, 2010)

mgraw said:


> Don't you mean pressure *decreases on the low side* and the unit kicks off on the low pressue control.
> 
> There are many ways these units can be wired. Some units have door switches that shut off the fans and solenoid valve when the entrance door is opened. Some have a switch mounted to the fan unit that may or may not be connected to a solenoid valve. Some fan units receive power from the condensing unit. Some fan units get power from a TC.
> Check with the refrigeration guy.


No,pressure increases due to closed soleniod valve. Compressor then cuts out. As far as i know, i could be wrong, it could be working that way also.


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## B4T (Feb 10, 2009)

Jlarson said:


> Just listen to the AC guy. He knows (or at least he should) how that model of cooler works exactly, we don't.


That _might_ be true.. but I like to ask you guys so I have more information than I started with..

More than once I have had the "trade experts" give me wrong information and I hate having to do something twice.. even if I am getting paid for it..


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## mgraw (Jan 14, 2011)

Shockdoc said:


> i could be wrong,


You are wrong.


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