condensser fan control for 404a

[tarcau mihai]

Hello guys!we have to install a tandem compressor 2nd hand for a costumer...the condenser in air cooled with 4 fans..we want to control the fans condenser in 3 steps
1st stage - all condenser fan off
2nd stage-2 fan run and 2 off
3rd stage - all 4 fans run
can anybody please sugest the pressure work for 404a for all 3 stages?
Regards Mihai

[taz24]

Hello guys!we have to install a tandem compressor 2nd hand for a costumer...the condenser in air cooled with 4 fans..we want to control the fans condenser in 3 steps
1st stage - all condenser fan off
2nd stage-2 fan run and 2 off
3rd stage - all 4 fans run
can anybody please sugest the pressure work for 404a for all 3 stages?
Regards Mihai


I would do it slightly differently.

1 fan constantly on and then the other 3 on seperate switches.

What discharge pressure do you want?
15 bar? 20 bar?

I will work to 15 bar but you can run any discharge pressure.

switching on
1st fan on always
2nd fan switch on at 15.5 bar
3rd fan switch on at 16.5 bar
4th fan switch on at 17.5 bar

switching off
4th fan off at 16.5 bar
3rd fan off at 15.5 bar
2nd fan off at 14.5 bar

once set up you can run very accurate pressures. If you are not too bothered about the discharge pressure you can widen the differential to 2 bar and the fan will run longer and stay off longer. But the discharge pressure will fluctuate more with wider diffs.

Cheers taz.

[tarcau mihai]

tks Taz for your replay!
when we will start the system we will see how to set the controls,but i prefer to keep the fan off on the first stage cause the condenser is a little big for this system and the outside temp in the winter here is -5C + 5C..also the owner show up today with a Fischer Fan Controller..i have to check the electrical diagram also for this on Google ...
Regards Mihai

[ChillyWilley]

i prefer to keep the fan off on the first stage cause the condenser is a little big for this system and the outside temp in the winter here is -5C + 5C


May consider a head master or flood valve. It may save you a call when it's sub zero and gusting out.

[Andy]

Hello guys!we have to install a tandem compressor 2nd hand for a costumer...the condenser in air cooled with 4 fans..we want to control the fans condenser in 3 steps
1st stage - all condenser fan off
2nd stage-2 fan run and 2 off
3rd stage - all 4 fans run
can anybody please sugest the pressure work for 404a for all 3 stages?
Regards Mihai

Hi tarcau muhai:)

don't forget to control your fans in groups of two, side by side so that hot gas does not end up in your liquid line.

Kind Regards Andy:)

[boy]

tarcau mihai,

you can control the fans one by one even on a single row of 6 fan motor as we have done before.

regards,