take control over carrier 69NT40 541-301

[raphluce]

Hi,
I'm a farmer, and owner of a carrier 69NT40 541-301 that I use to keep my vegetables fresh.
It works like a charm but is very noisy. Compressor starts often, and the fans turns all the time and too strong.
Manual is here (https://drive.google.com/file/d/1y3SuRPIDTPE_8u-4OAJF6GiLJQgIFZ1M/view?usp=sharing).
I'd like to be able to :
- Stop the unit with a timer.
- Reduce fan speed and/or stop them from time to time.
- if possible stop the fans each time I open the door.

Has some of you done it before ?
I tought about putting a relay after the manual start/stop switch to stop the unit during with a timer, but I don't know if it will like to be stopped/started like that 4 times a day. (or even more if I stop it when I open the door)

2nd option : putting a relay before compressor and fans. Do you think it is possible to stop a compressor like that without danger ?

Hope someone can help. Have a good day

[Brian_UK]

It would be better to interupt the (ST) Start/Stop switch using something like a four pole contactor/relay operated by a timer.

Ensure that there is a proper start delay timer incorporated to prevent rapid restarts of the compressor unit as that is the fastest way to kill a compressor. Something like a maximum of four starts per hour.

According to the manual the condenser fan should be pressure controlled so perhaps that circuit needs checking over. We are assuming that the condenser coils is clean and clear.

[raphluce]

Hi,
Thank you very much for your help.
Ok, i'll trybthe 4 pole contactor/relay on the on/off switch.
Seems to me that The condenser coils are quite clean.
But, about the fans, i wasn't talking about external condenser fans (cause I assume that it is running depending on condenser needs) but about internal fans, the ones that cause the fresh air flow : i reduced the container volume by three adding a wall, so I don't need such a strong air flow inside it and I would like to reduce the speed, if possible. If you have an idea about how to do it, would be great !
Thanks a lot. Have a good day

[Brian_UK]

Okay, so it is the evaporator fans that you are trying to adapt.

Quick read of the manual suggests that there are two types of fan systems fitted, do yoou know which type you have?

Also have a look at section 4.4 of the manual, something there might help ???

[raphluce]

Hi Brian. Thank you for your answer.
I'll have a look at the model as soon as I can (for the moment it is filled with products - difficult to access the fans).
Have a good day.

[charlie patt]

Has to be said a 69 nt on veg is a bit like using a mini digger to crack a walnut I would suggest perhaps installing a standard dixell or Elliwell controller to controll the contractors as you want them you can then control fans via door switches and use the controller to alter hysteria etc I would of thought the current set up is drying your product out rapidly there is enough contractors on that unit u can control what you wish

[raphluce]

Hi Charlie. Thank you for your answer.
Yeah, my nuts are well cracked :)
I'm ok with the idea to use an other controller, But i fear to do mistakes in the wiring or to miss an important concept in the way a compressor works (in terms of security).
Do you think you could help me a bit to design that ?
(I'm ok with basic electronics, soldering, can program arduino's if necessary etc...)
Thanks. Have a good day.