Considering charging a 7 yr old Carrier packaged heat pump 3 ton unit

illanrob

I am considering charging with R-410A a 7 yr old Carrier packaged heat pump 3 ton unit now that it is out of warrantee for all parts and labor.

I must say charging an automobile AC in the comfort of a garage, as I have for many years, seems easier and less risky than the home HVAC.

I removed some of the packaged unit side panels, saw the compressor and the evaporator coil. I was looking but not very hard for the low pressure charging nipple and the high pressure nipple, but did not see the red/blue covers that automobiles have.

Is there a sight glass in these systems to look at bubbles?


This unit has been serviced for evaporator coil leaks twice within warrantee and when correctly charged works great.

The cost of R-410A is $155 for 25lbs gauges are $100 or less in the internet, while AC contractors charge for R-410A $35/lbs and higher. This cost is part material and part labor waiting for the freon to charge.

bill01

So I was going to be a smart ass and ask how you manged to get your EPA license to buy 410a and don't know this and come to find out you can buy this with no license even though you need a license to "handle" it whatever that means.

Don't even think it is close to as easy as a car. In fact you most likely were doing the car wrong also...did you use a vacuum pump to remove all the air?

First the unit must use 410 you cannot put 410 in a r22 system. Be nice with the freon 22 price increase if you could just put in 410. Gotten to the point you might as well toss older r22 systems because of the cost of the gas.

You will need to buy a gauge set designed to work with 410 it runs under much higher pressure than other coolants. The charging pressures are all based on temperatures you must measure...like you are suppose to do on a car also. There is some variation between models and brands so be sure to check there are not special requirements for your unit. This is very basic AC stuff, you shouldn't touch systems if you do not understand how to read the tables.

I would not recommend you even attempt this yourself. If you damage the compressor you will be out far more than you will have saved doing it yourself.

illanrob

Thanks for the reply. The AC contractors that serviced this Carrier packaged unit only evacuated the R-410A when replacing a part that handles the refrigerant, else they just add refrigerant and verify that the AC is cooling properly. I even heard from consumers that buy service warrantees, if topping a leaky system with refrigerant is sufficient to get it going, then that is all that they will do. The EPA may not like it but HVAC contractors and their manufactures, like Carrier, do not care to repair a leak when topping with will do the trick. This even when their maintenance manuals say to isolate and repair a leak when refrigerant is lost.

R410 is environmentally friendly compared to R22. I never mentioned R22, autos use R140 ( or such), residential use R410. R22 is priced higher than R-410 but not twice as much. I never said that I did not know how to read temperature/pressure tablesor that R-410 operates at higher pressures.

I gather, from your reply, that residential HVAC units do not have a refrigerant sight glass as in automobile systems.

Thanks for your comments.

hvactech126

autos use R12 and R134A! Residential a/c uses R22 and R410A. I have not seen an automobile system with a sight glass. Do you know how to measure superheat and subcooling? You said the system is 7 years old, are you SURE that it used R410A? R410A is not a drop in refrigerant to replace R22. They contain different types of oils. You MUST use a vacuum pump to remove all air and moisture from the system before charging if it has no charge currently in it. If you don't you will create an acid condition in the system which will burnout the compressor. Get your EPA certification and then come back.

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RDH1958

You must pull a vacuum in all a/c units or acid & moisture will be a problem. Yes many cars & trucks used sight glasses many were right on the drier. None as far as I know use them today with r134a or the new 1234yf.
I see alot of people trying to save a buck or so I have an auto shop many people doing work they shouldn't be doing either brakes,front end work,steering. So to each there own I guess it's the installer who will pay the price instead of a family driving down the road. JMO

Marty S.

No sight glasses on 410A because it will bubble from the pressure drop of going from the 3/8 liquid line to the larger chamber in the site glass even with a full charge. R410A has a higher greenhouse effect than R22 but does not destroy the ozone. R22 is more than twice the price you listed for 410A,closer to triple.