Package Unit Condensing Fan

If the package is piped so that each compressor has its own fan, you can shut off the compressor in question. If all the compressors discharge into a common header to a single condenser, you can shut off any of the compressors. Of course, the whole unit will lose some capacity, but it should still balance reasonably and avoid high discharge pressure cutouts.

You may also have to block or cap the opening to the non operating fan. Often the other fans will draw air backwards through that opening rather than through the condenser. - JHF

Replacing a condenser fan on a multi-compressor packaged unit does not normally require disconnecting or removal of any compressor(s).

Commercial/Industrial packaged HVAC units unless modified, are designed for online maintenance of the condenser fans.

You should be able to remove the fan shield, disconnect the bad fan, and remove it without impacting the other fans or compressors.

Be careful when disconnecting the fan motor leads with power on the terminals/connector and be sure to wear the appropriate safety equipment including safety glasses and gloves.

If there are not individual switches on the condenser fan leads I would consider installing a switch on the fan you are replacing as well as on each/every fan that you replace in the future until all fans have a safe means of disconnect.

If you do not know how to safely perform these functions it is in your best interest to hire a competent, reliable, trustworthy HVAC technician to do the work and they can walk you through the procedure step-by-step.

What were the recommendations made during the recent telephone call to the equipment supplier for advice, and why have they not been carried out already?

That condenser fan is there for a reason! Disconnecting it or the associated compressor will not solve the problem, if anything it just might magnify the problem.

Your in over your head! Cut your losses and follow Fredski's suggestion and hire a professional who works on these systems. I've worked on these systems and larger and they are not for DIY novice. These systems are balanced and unless you know and understand how each component inter-acts with the other, you should not attempt any short-cuts.

Darwin's nominations anybody?

I don't know how you got into your current job position, but if you plan on staying there you really need to take a HVAC course that covers theory and principals and electrical systems and controls.

At least you won't be asking " if " questions, you'll know if you can plumb 100% fresh air into the system or if you can replace one 10 ton compressor with two 6 ton compressors of if you can de-rate a system because of a bad condenser fan. Go to school, open the books and learn something. It's a lot cheaper and safer than the school of hard knocks that could kill you from a lack of experience