Advice on A/C condenser

[Stan Croenne]

I just inspected a 25 year old A/C condenser unit with considerable deterioration from urine. The system is in working order. I think it needs replaced, how do you report this? Thanks, Stan

[kluce]

Originally Posted by scroenne

I just inspected a 25 year old A/C condenser unit with considerable deterioration from urine. The system is in working order. I think it needs replaced, how do you report this? Thanks, Stan

Keep it simple.

The unit is old, the fins have deteriorated due to dog urine which decreases the efficiency even more and there is a chance that a freon leak can develop. Due to the age of the air conditioner, replacement is recommended at this time. If replacement is not done at this time, reserving funds for replacement is recommended.

[David A. Andersen]

I think it needs replaced,

Why?

What test did you do to determine this significant efficiency loss?

[Wayne B. Wilson]

Damage to the coil Fins Noted, Unit is working at the time of the inspection . However this system is beyond it's designed life and the is no way of forecasting time left for operating with no problems. Recommend a qualified HAVC contractor to evaluate . Consideration for replacement may be needed.
You could add because of the type of damage small leaks could pose a problem in the future.

BTW most unit's can loose about 30% of the fins before it is a problem ( at least that is what i was taught many years ago ) not sure if that still holds true. Maybe David can enlighten us .

[David A. Andersen]

Yes, you're probably correct. A lot has to do with the system design and the current weather conditions as to how much efficiency loss occurs. The system is designed to operate in conditions below maximum capacity design. So until weather conditions maxes out the unit for what it was designed for, you'll never even notice the fin loss.

How often does your equipment operate at maximum capacity? Not very often and when it does, it's not for very long. (That is if it was designed correctly in the first place).

So, if you leave the windows open in your house on a 105° day with a 98% relative humidity and you take a piece of plastic and start to cover up the fins on your condensing unit, watching the refrigeration pressures, you will see how much coil you can afford to lose.

If you're not into refrigeration pressure, you can put on an amperage meter and cover-up probably twice as much coil before you see an increase in power consumption.

The copper piping does the majority of the work. The fins simply increase the efficiency of heat transfer to the pipe.

You can't reduce the length of the pipe, but you can eliminate a large amount of fins and not drastically effect capacity/efficiency.

So why do they put fins on there in the first place? Because over the life of the unit, a small amount of increased efficiency adds up to a substantial amount.

This 25-year-old unit is not going to last long enough to substantially put your home buyer in the poor house.

[Wayne B. Wilson]

I figure it was still the same David but i am getting old and grey just wanted to check if it was still a rule of thumb

[Wayne B. Wilson]

Btw has anyone have a pdf file with different refrigerant Preasure's and temp chart?

[Bruce A. King]

Originally Posted by scroenne

I just inspected a 25 year old A/C condenser unit with considerable deterioration from urine. The system is in working order. I think it needs replaced, how do you report this? Thanks, Stan

Your client is paying you for your opinion, don't be afraid to give it.
The age is the problem, the other things are just typical for a unit of this age.

Its $4k to $5k for most systems, if your client buys the house and does not know this, you failed them.

[Wayne B. Wilson]

I meant to ask is temperture presure chart

[David A. Andersen]

Google it. They are all over.

http://www.chillers.com/PT%20charts%...frigerants.htm

If you know the temp: http://www.csgnetwork.com/r22presstempconv.html

[Wayne B. Wilson]

Thanks David i had a grey moment , I thought of google after i posted it

[Stan Croenne]

Great info. Thanks guys. Stan