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Discussion Starter · #3 ·
thanks..
I bought a fieldpiece subcooling and superheat meter........I have not used it yet.....im going to read up on the instructions and go that route on charging by superheat and subcooling........can you charge a system when it is cold out?......On r-22 you can wrap the condensor with a tarp and clear the sightglass to fool the unit....is that a good way to do it and if it is, would that work for 410a......and does this make sense to you ?
 

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If life were only that simple. I use the charts that give you superheat and subcooling and (Lennox, approach) methods and are included with the unit. You have a lot to learn but we will try and help you if you have a bit of thick skin. You have to understand the type of load (heat, humidity) airflows and how they affect a unit. A lot of different conditions can affect charging a unit an fool you into overcharging etc. A dirty A coil will slow down the air/lower suction pressure etc so I would recommend you do the NATE courses and learn about all this. I will rarely charge a unit when it is less than 70 deg F outside AND you need a load in the house. Wrapping the condensor rarely is accurate and unless you have LOTS of experience it will go badly for you and generate lots of callbacks. Lennox has lots of internal training courses for their dealers and if you deal a major brand then check with them if they have one for you. Make sure you understand all the dangers of working with high pressure refrigerants. Safety glasses, gloves, NO damaged or dubious quality hoses.:yes:

Good Luck
 

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Using a tarp and clearing the sight glass isn't a great way to charge in cold climate conditions.

A tent, or tarp is find.
but, you need to have the subcool for those outdoor temp conditions you are simulating.

If its a piston/fixed metering system. then you need to simulate a warm/hot out door day, that matched the indoor conditions.

Simulating a 95° outdoor temp, with a 50° indoor wetbulb, won't get your charge correct.

With that indoor condition, a 60° outdoor temp would be what you would simulate.
 

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I would also get a set of low loss fittings for your guage hoses..don't use the same hoses / fittings with R410 & then try to use them on R22... Make sure your hoses are rated for the pressures of R410
 

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Discussion Starter · #7 ·
Thanks for help Beenthere and Yuri......
I bought a 410a book today and going to read up on it....I'm going to take the class next month. I want to be ahead of the class I have installed units in the winters(410A)....brand new systems...all 9 yards...ducts,piping and etc.... installed a sight glass and drier. I measured the pipng to the exact or closest feet of Refrigeration lines....leak checked, pulled a vacum on system and weighed in correct ammount of 410a for the length of pipe run...I've put in about 10 systems over the winter and as the weather starts to get warm, I will be ready to check theses systems for proper operation......
thanks all for your time
Paulie Pizza
 

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with the unit not powered up....and the VAC completed go right to the king valve on the condenser with a single hose and the 30lb drum of freon.connect the hose to the upright tank crack the tank to bleed a slight gas pressure and hook it up to the king valve and open it half way.open the tank valve 100% and flip the tank......liquid will fill the LL into the air handler and the bottom of the condenser till the pressures equalize.you are now 80-90% charged without even running the compressor:whistling2:.shut the freon tank off all the way up on the king valve stem to full open running position disconnect the single hose.the rest if any of the charge will be determined by the SH/SC readings with some what of a load on the evap coil...check your amps on the runnibf compressor inlet air into the condenser pus 30F to see how the head is wit the days temperatures.then fine tune it with those readings..forget the sight glass being clear:huh:if you have a laser thermometer hit the bottom bends on the condenser working your way up the rise in temp will be the difference between the liquid and the hot gas.2 to 3 rows on the bottom for liquid.
 

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Thanks for help Beenthere and Yuri......
I bought a 410a book today and going to read up on it....I'm going to take the class next month. I want to be ahead of the class I have installed units in the winters(410A)....brand new systems...all 9 yards...ducts,piping and etc.... installed a sight glass and drier. I measured the pipng to the exact or closest feet of Refrigeration lines....leak checked, pulled a vacum on system and weighed in correct ammount of 410a for the length of pipe run...I've put in about 10 systems over the winter and as the weather starts to get warm, I will be ready to check theses systems for proper operation......
thanks all for your time
Paulie Pizza

I'm gonna have to talk to my Godfather. If 'da pizza guzys is gonna cross into our territory wez is gonna do 'da same. How do you guys like your pie?

Hey Beenthere, by pass the slef cleaning lock on the kitchen stove. We got pizza to make:laughing::jester:
 

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I'm gonna have to talk to my Godfather. If 'da pizza guzys is gonna cross into our territory wez is gonna do 'da same. How do you guys like your pie?

Hey Beenthere, by pass the slef cleaning lock on the kitchen stove. We got pizza to make:laughing::jester:
LOL...

Acouple years ago, I could have got you 2 of Dominos old electric pizza ovens.

POS from day one.
 

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Dominos is headquartered here.

Pizza sucks. We have a large local chain franchise called Jets. Cheap price but taste great!

Just had some an hour ago and my mouth is watering thinking of it.
 

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There is only one place around here that makes good pizza.

And its not D's or PH.
 

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Discussion Starter · #17 ·
yes other than pressure difference between 22 & 410a
remember 410a is a blend
it must be added as a liquid
i,m an hvac-r service tech
Thanks dbmarsbrit,
As I keep reading up on 410a.....weighing in the charge in a liquid form and pressure's are higher than 22.....I still put a sight glass,drier and deep vacum on system before I put in additional charge needed. I have a chart on ammount needed for total run of pipng..... and it works great

Lately we have been installing drier as close to A/H to catch anything just before TXV......does that make a difference to install in attic or by the condensing unit...other than the drier getting hot in attic...I have taken old units out with drier in attic.....
 

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Thanks dbmarsbrit,
As I keep reading up on 410a.....weighing in the charge in a liquid form and pressure's are higher than 22.....I still put a sight glass,drier and deep vacum on system before I put in additional charge needed. I have a chart on ammount needed for total run of pipng..... and it works great

Lately we have been installing drier as close to A/H to catch anything just before TXV......does that make a difference to install in attic or by the condensing unit...other than the drier getting hot in attic...I have taken old units out with drier in attic.....
Can't use a sight glass on a zeotrope refrigerant to check charge. Can have bubbles cause of the slight temp glide characteristics of the refrigerant.
 

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Except for systems that had a receiver. Sight glasses were never a good way to determine if the system was charged properly.
 

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Thanks dbmarsbrit,
As I keep reading up on 410a.....weighing in the charge in a liquid form and pressure's are higher than 22.....I still put a sight glass,drier and deep vacum on system before I put in additional charge needed. I have a chart on ammount needed for total run of pipng..... and it works great

Lately we have been installing drier as close to A/H to catch anything just before TXV......does that make a difference to install in attic or by the condensing unit...other than the drier getting hot in attic...I have taken old units out with drier in attic.....
the only difference is you may not catch any contaminants in the linset
between the drier and the a/h txv
I haven't seen a txv system that doesn't have some sort of internal
screen/filter adding a liq. line drier at the or as close as possible
to the txv is prefered hot attics are not really an issue
on large commercial units suc.&liq. filter driers are often open to the elements/sun
 
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