Puron Charge by weight

[crabjoe]

So finally, I was able to get a full bottle of acetylene and a torch to finish the brazing... I still need to get finish the electrical on the new heat pump..

With that said, I want to get my charge right, as right as it can be by weight, so when the electric is hooked up, I'm good to go....

I ended up using 46 feet of line set. The heat pump states that it came with enough R410a for 15ft of 3/8 liquid line and the factory dryer (.6oz for each additional feet of liquid line)... So here's my numbers.. I just want o make sure they look good since I can't charge by SH/SC.. Can anyone confirm the numbers?

46ft - 15ft = 31ft.
31ft * .6oz = 18.6 oz of R410a.
18.6oz = 1.1625 lbs of Puron.

BTW, I can't remember how many decimal places my scale goes out to... So if need be, would I better better off adding 1.1lbs or 1.2 lbs of Puron ... assuming my numbers are good?

Thanks all!

 

[zmaxmotorsports]

Charge it by pressure,weight will get you in the ball park but will still need to be fine tuned.

 

[Milton Shaw]

R410A operates at a lot higher pressure, make sure your gauge set and hoses are for the high pressure, otherwise you might loose all your charge if you have older hoses. Make sure you charge with the valve down on the tank as you have to charge liquid on all the blends or you don't get an accurate mix of the components in the tank. (4 or more different chemicals mixed to make R410a.)

 

[crabjoe]

Guys,

I know weight will only get me in close, but I was told not to charge by pressure when outside temps are below 70F. That's my problem... When I get time to work on these things, the outside temps are in the 50s or low 60s... Because of this, I figured I'd charge by weight and when I get a nice day, with outside temps at 70+, I'd check and adjust the charge based on SH/SC.

With that said... does 1.1 or 1.2 lbs of R410a sound right?

BTW, charging by pressure when it's cold out.. what's about the lowest temp I can do this at or was what I was told 70F correct?


Thanks!

 

[bazar01]

Guys,

I know weight will only get me in close, but I was told not to charge by pressure when outside temps are below 70F. That's my problem... When I get time to work on these things, the outside temps are in the 50s or low 60s... Because of this, I figured I'd charge by weight and when I get a nice day, with outside temps at 70+, I'd check and adjust the charge based on SH/SC.

With that said... does 1.1 or 1.2 lbs of R410a sound right?

BTW, charging by pressure when it's cold out.. what's about the lowest temp I can do this at or was what I was told 70F correct?


Thanks!

Did you buy the new HP unit dry? Nitrogen charged? Or is this a used one?
Open the condenser unit cover and check the charging chart for the lowest outside temperature and corresponding SH/SC and charge by pressures.

 

[crabjoe]

Did you buy the new HP unit dry? Nitrogen charged? Or is this a used one?
Open the condenser unit cover and check the charging chart for the lowest outside temperature and corresponding SH/SC and charge by pressures.

It's new, so it should be marked clearly... Thanks for the info!!

 

[Jackfre]

You don't say who the manuf is. Unless they are specifically calling for a pressure reading on charging the weigh-in will be fine. If you are worried about the low temp side, just make sure the cylinder has been stored in a nice warm area. It won't take long to put in a lb+ of refrigerant. Do make sure the bottle is standing upside down. Charge from the bottom with liquid.

 

[Ohmthis]

When charging by weight I always reclaim whats in the unit and weigh in the total weight required. Most units across several manufacturers aren't filled to the factory weight. How are you going to add charge without running the unit? When in doubt, always go by the manufacturer Installation manual.

 

[crabjoe]

Ok.. Got home in time where the outside temp was 61F, which allowed me to charge by subcool (TXV). I couldn't do superheat since there wasn't a recommendation on the chart. I had it slightly over charged.. Had to drop it from SC of 20 to 17.... Even though I got the SC to where it needs to be, I'm having a hard time with it being that high...

Have any of y'all seen a recommendation for SC that's above 15?

 

[Ohmthis]

What unit do you have? It should have the SC on the name plate or on the back side of the electrical panel. Give use the model number so we can see the specs.

 

[brewchief]

I've seen heat pumps that had a high SC number in cooling but would end up in low single digit SC in heating, set it to the units spec and run it.

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