# Cold Weather Charging For Air Condition



## IRISHADAM711 (Mar 8, 2008)

Does Anyone Have Any Tips On How To Charge An Air Conditioner When The Temps Outside Are 48 To 55....??or Lets Just Say Under 60.f 
I Have Heard People Talk About Putting A Plastic Bag Around The Unit Or Heating The Inside Of The Home To 75. But No Info On How To Really Perform The Charging.
Its Still Cold Here In Michigan And I Have Alot Of Start Ups To Do.


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## hf05 (Mar 14, 2006)

Hi if theres a ambient sensor on the unit it probably won't start anyway.The most accurate way to charge a unit would be to weigh it in according to condensor specs..or wait till it gets a little warmer and superheat calculations will tell if your over or under charged


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## Geno54 (Jan 19, 2007)

IRISHADAM711 said:


> Does Anyone Have Any Tips On How To Charge An Air Conditioner When The Temps Outside Are 48 To 55....??or Lets Just Say Under 60.f
> I Have Heard People Talk About Putting A Plastic Bag Around The Unit Or Heating The Inside Of The Home To 75. But No Info On How To Really Perform The Charging.
> Its Still Cold Here In Michigan And I Have Alot Of Start Ups To Do.


Wrap a plastic bag or tarp around the condensing unit to elevate the condensing pressure to about 200 # (abt 100 deg) on 22. It is a rough way to charge because it is difficult to maintain steady pressures and the load inside although 75 deg will drop off quickly because of no external load entering in. And you need some time to get an accurate charge. So you can guestimate with this method but you will most likely be back to correct the charge when it gets warmer. So like hf said, best to weigh in the charge and be done with it.


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## Verbal (Jul 9, 2008)

*Cold weather charging*

This method works well, although it involves covering the coil on the condenser to match a simulated head pressure.

needed:
tape
contractor garbage bags
testing manifold and gauges
sling psycrometer

1. First get the return air wet bulb temp 58f or higher. 

2. On the charging superheat chart (or universal charging chart)
find your WB temp, and go down the column till you hit the first set of double digit superheat numbers. Now go across the chart to find the corresponding outdoor temp.

3. Find the SEER rating of the unit you are working with, and find out the typical condenser temp split for that SEER. (see below)

4. Add that number to the outdoor temp from your charging chart.

5. Now find that temperature on the pressure/temperature chart for the refrigerant you are using.

6. Now cut the contractor trash bags along the sealed seam on the bottom, and down one side. put one on each exposed side of the coil, and tape them in place. As the pressure rises, peel the bags bag evenly along all of the sides until it stabilizes at a head pressure that matches the one you got from the temperature/pressure chart.

Now balance your superheat/subcool

*Typical Condenser TD

SEER* _*TD*_
6-7 _30_
8-9 _25_
10-11 _20_
12-13 _15_
14-16 _10

EX: (using universal charging chart on R22)

My WB is 58°__ (taken at the filter rack), on the chart 13° superheat is my first set of double digits. The corresponding outdoor temp is 70°. On a 7 SEER unit the TD is 30°, 30°+70°=100°. Find 100° on the temp/pressure chart, it gives me a pressure of 195.9 psig. Cover the coil evenly to bring the head up to 195.9 psig. You just simulated a 70° day. Now balance you SH to 13°_


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