USE OF EXISTING PIPING WHEN CHANGING OUT AIR CONDITIONER AND AIR HANDLING UNIT 1

[sailoday280]

Presently the lobby of our building is cooled by a 10 ton Air Conditioner --- the compressor and condenser are located about 150 ft from the bldg. An inside air handling unit with and evaporator is located in the bldg. Air conditioner compressor, evaporator, etc are about 30 yrs old and are to be replaced. Refrigerant will have to be replaced to meet present standards. To save on costs, can the existing buried piping connecting the compressor, condensor with the evaporator be used with the new refrigerant.
Thanks

 

[berkshire]

One thing to look at, is the type of replacement refrigerant you are contemplating. Some of the 400 series refrigerants have much higher working pressures than the older R12 or R22 refrigerants that were commonly used. Using the newer refrigerants on an old line set, without some testing, is not recommended.
B.E.

You are judged not by what you know, but by what you can do.

 

[EnergyProfessional]

Talk to manufacturer if the layout would work with their equipment. different manufacturers have different strategies for oil return etc. and for an all new system would prescribe the pipe inc. sizes. You may think if your existing pipe is larger it would work, but often they require smaller pipes for oil return etc.

 

[Drazen]

It cannot.

There are some special substances for chemical cleaning on market, but the issue is whether chemical supplier could supply you a warranty that his process will not make damage to the new equipment.

If you want to save, you could also consider overhaul of the old compressor, many such units are of good quality and can work very long time with proper maintenance, and it is commercial guys aggressiveness that put such stuff out of business.

On the other hand, if you hunt modern concepts of energy efficiency such compressors will not be adequate, but than there is no way to be cost efficient. If you want to be cost efficient, keep the old stuff as long as possible.

 

[EnergyProfessional]

I think 30 years is the end of useful life. You prbably already have leaks all the time, and other repairs with cost and downtime. This is lokeonwing a vintage car, not really what you want as your daily driver.

In addition R12/R22 are so expensive now, any leak will cost you dearly. This unit probably had a useful life of 20-25 years.

Spare parts also will be harder to come by as it ages.

Get it all new and be good for the next 25 years.

 

[sailoday280]

Please note, the main unit (compressor, condenser, evaporator, etc) is to be replaced. The question is --what concerns are there with regard using existing buried piping (150 ft)when the refrigerant is replaced (say R410 vs R22). With regard to flow resistance, I would think the expansion valve is major resistance for pressure drop. Specification for replacement probably include pressure testing of existing piping. Please provide pro's and cons and other suggestions.

Thanks again.

 

[york83]

Personally I would say replace the existing piping. Being that it is buried and going from a system with one type of oil to a system with a much different type of oil could cause problems in the future. Have contractor run new, clean ACR piping above ground if possible. More cost up front but the possibility of less headaches in the future.

 

[EnergyProfessional]

Let me ask you this: if you buy a new car and have a 15 year old beater, do you go to the car dealer and ask him to order a new car without seats because you want to save money and reuse your old seats? Your dealer probably can somehow install the old seats in your new car. But now answer this: Is this a good idea?

 

[317069]

Both Drazen and York83 gave you two logic ways to go with this project, you can choose one of them but mixing between them is not a good idea, you want to replace whole major units, why are you worry about 150 of pipes

 

[sailoday280]

317069 (Mechanical)
Cost of labor,etc for removal. If piping can be used then it is a substantial cost savings when doing the replacement.

 

[EnergyProfessional]

I provided 2 engineering answers and you didn't understand them. My 3rd reply repeated the answers in civilian terms. Refrigerant piping is part of the refrigeration system and specific to the units. It doesn't make sense to try to scavenge it and possibley have problem later on.

You should hire an engineer to design the project for you. If you hire and pay an engineer, you can comandeer that person to provide you what you want. Here we give free advice, and reply in whatever manner we want to.

 

[willard3]

The best way to save money is to do nothing and suffer with what you have........if you want to do this correctly, replace the whole system, piping and all.