On remote unit, will t-stat directly control the compressor on and off?

[david2008]

for commercial refrigeration

[Brian_UK]

It will control it but probably via a contactor or other start device.

[david2008]

It will control it but probably via a contactor or other start device.

Could you give an example? Thanks.

[Brian_UK]

Could you give an example? Thanks.

You jest surely ?

[david2008]

You jest surely ?

I am rookie.

[monkey spanners]

Could you give an example? Thanks.

Have a look on youtube for vids on refrigeration contactors etc, i have tried to put a link in but can't get them to work for some reason


Jon

[david2008]

Thanks Jon. If the remote condenser is located 300feet away, does it need 300feet long wiring?

[monkey spanners]

Hi David,

It depends on the system, you could wire the condenser fan/s back to the compressor control panel, or you could run it off a pressure switch or fan speed control so it will start up once the system pressure rises.

As the tech installing the sytem the choice is yours, many factors will influence your decission as to the best method for the system in question.

300ft is a long distance for a remote condenser, much thought would need to be put into pipe sizing and routing.

[david2008]

It makes sense. Thank you Jon!

Hi David,

It depends on the system, you could wire the condenser fan/s back to the compressor control panel, or you could run it off a pressure switch or fan speed control so it will start up once the system pressure rises.

As the tech installing the sytem the choice is yours, many factors will influence your decission as to the best method for the system in question.

300ft is a long distance for a remote condenser, much thought would need to be put into pipe sizing and routing.

[Brian_UK]

I am rookie.

OK David, fair comment.

There are some wiring schematics on this Emmerson link which may prove useful.

http://www.emersonclimate.eu/literat..._C070901_0.pdf

Regarding your later question about 300ft....

If there are fair distances between indoor and outdoor you may often find that the power circuits/supply are adjacent to the outdoor unit and a low(er) voltage signal wire will be used from the indoor unit. So wiring diagrams, although compact, can cover a large area.

[david2008]

Thank you Brian. I will read the pdf file you provided. 300feet is just an “if” number. It looks like too far…….. what is a average distance for remote system? Less than 100 feet?

OK David, fair comment.

There are some wiring schematics on this Emmerson link which may prove useful.

http://www.emersonclimate.eu/literat..._C070901_0.pdf

Regarding your later question about 300ft....

If there are fair distances between indoor and outdoor you may often find that the power circuits/supply are adjacent to the outdoor unit and a low(er) voltage signal wire will be used from the indoor unit. So wiring diagrams, although compact, can cover a large area.

[Brian_UK]

Remote can be just outside the building or across a car park.

[Royal241]

Hey, the t-stat controls the selenoid (pump down system in your case) located next to the evaporator, low pressure contro; shuts dowm compressor. No, you don't need a 300' wire, that extra wire will kill your compressor sooner than you might think.

[david2008]

Thanks for response. I understand your post that solenoid and low pressure control can work together to on and off the compressor. Just now, when I read the online information, there are also high pressure control and dual pressure control. How did the high and dual pressure control work to make compressor on and off? Do they still use solenoid? Thanks. David.

Hey, the t-stat controls the selenoid (pump down system in your case) located next to the evaporator, low pressure contro; shuts dowm compressor. No, you don't need a 300' wire, that extra wire will kill your compressor sooner than you might think.

[monkey spanners]

High pressure switch turns the compressor off if the condensing pressure get to high for some reason, e.g. dirty condenser, failed fan motor, very high ambient temperature. A HP switch can also be used to cycle condenser fans on and off on multi fan condensers to keep a more constant condensing pressure.

A dual control is just a Low pressure and high pressure switch combined into one housing. (Be carefull when swaping diffent makes as a replacement because some are LP/HP and some go HP/LP so if you put the capiliaries on the same side you took them off they would then go to the wrong switch!!!)

Jon

[david2008]

Thank you Jon!

High pressure switch turns the compressor off if the condensing pressure get to high for some reason, e.g. dirty condenser, failed fan motor, very high ambient temperature. A HP switch can also be used to cycle condenser fans on and off on multi fan condensers to keep a more constant condensing pressure.

A dual control is just a Low pressure and high pressure switch combined into one housing. (Be carefull when swaping diffent makes as a replacement because some are LP/HP and some go HP/LP so if you put the capiliaries on the same side you took them off they would then go to the wrong switch!!!)

Jon