Best way to charge or adjust split system.

[pliscon]

What is the desired Delta t over the coil? It is hard to check it unless I drill a hole in the plenum. Is there any OEM chart available for luxaire units.. Knowing the properties of freon and the CFM required I would think that one OEM chart would be pretty close to the other. They all want 400 CFM/Ton, and the properties of 22 dont change.. It seems the oriface may be one size too large. I used the manual which matched one of the oriface which came with the condenser.. However it is the same manual that told me to over charge my system... Mabye with a different oriface it would not be overcharged... Shrug

[Shophound]

If I was still in the change-out/startup side of this trade, I'd right out of the chute toss out factory charge as being reliable. Why shoot the system in the foot from the word "go"?

I think you're already seeing this for yourself, being you wrote you have to remove refrigerant on many systems when you open the factory charge into the lineset and evap.

My last reply was to address the performance of your own system. I now understand you know it's overcharged...I was trying to drive home the often overlooked fact that piston orifice systems are CRITICAL CHARGE. Yet one more reason I'd toss the factory charge level out the window as being reliable. Sometimes it will nail it, more often than not it will not.

If every resi tech out there riding herd on a set of gauges could grasp this concept, think how much better the world would look upon the HVAC trade with so many piston orifice systems with the proper charge!

[prodiyer]

Have you ever been to any of the equipment manufacturing plants ?

[pliscon]

And another thing.. I ordered my system with a Txv valve. Since it was Luxaire the TXV came seperate and I was in a hurry because I had company coming for the 4th. And I silver solder all of my units and did not have brazing equip here at the time of installation. It was very specific that the TXV had to be brazed which I dont really understand. So I installed the pin instead. I could still install the TXV it it would greatly help me. Why do they tell you to braze it? Same pressures as the lineset connections.. I can understand brazing the compresser..

[prodiyer]

Call a pro !

[pliscon]

The little overflow or balancing line on the Txv is what I am talking about being brazed.

[Shophound]

What is the desired Delta t over the coil? It is hard to check it unless I drill a hole in the plenum.

I'd look for a delta T between 16-20 degrees. Humidity levels will affect delta T as a higher humidity level translates to a higher latent heat load, thereby reducing sensible heat removal capacity. You will see the delta approach the 20 degree split on less humid days with normal interior heat loads and drop off toward 16 degrees with higher humidity under similar interior heat loads.

Fan speed will also affect delta T. If you find that no matter what you do with charge and your orifice size is correct, and the performance still sucks, drop the blower speed one notch and then recheck the charge, delta T's, superheat and subcooling readings. Many air handlers come from the factory set at high speed in anticipation of being installed into crappy ductwork. Yours may have a lower static, therefore better flow, and you don't need factory high speed.

As for your TXV question, are you saying by "silver solder" you're using the same stuff a plumber would on water pipes? I would go with brazing on any refrigerant piping system, bar none. Some TXV's may have brass bodies with copper coatings, thereby the OEM may want brazing performed so you won't be wondering why the hell you can't get the valve to sweat up using anything else.

[pliscon]

Call A pro? What do you mean by this. I am learning, I have been to training on Heil and Trane, Do I know everything... Ah... No I am trying to learn. Are you a pro? Once you were where I am at. I feel I have a pretty good understanding of what I am doing. I am just looking for some insight for some more information and knowledge so I can someday be as brilliant as You..


Laugh.

[Jultzya]

Originally posted by jultzya
BTW, if you take a suction temp (EST/STE) at the evap as well at the condenser, it will provide you some in-site of the systems operation.

Now get the EST and new ST!

[prodiyer]

I gave you very good advice on not trusting the manufactures charge and you blew it off.

[pliscon]

Silver solder is acceptable for R-22 systems. On higher pressure systems it is not. I have always used it, and every contractor around here does as well. Silver solder is much stronger than 50/50 solder or Taramet. It is a different solder than we use for water systems. This chart that one guy posted on this thread is that any good... It is the link to Ebay for the superheat and subcooling slide rule..

[pliscon]

Hey Prod.

I did not blow it off. It just seems something as simple as putting a certain charge in condenser when it leaves the factory is not rocket science. And from my on experiences out of probably 100 or so systems I would say that 98% of them end up over charged when I add Freon as instructed in the manual. Now what I am trying to learn is am I doing something wrong.. Are my gauges wrong, Is my Scale Wrong, My thermometer wrong, or is every condenser overcharged when it comes from the factory. Why do they print that in the manual, in regards to adding the freon. I use my universal OEM Chart which I think I am doing the right thing, then my supplier or some other tech tells me that it is ok to charge the system per manual. This is crap. And I actually take the time to check the readings and try to do the right thing. I just get sick of putting freon in and then taking it out. If I dont add any sometimes I still have to take out to get my desired SH. I usually install Oriface metering because the seer rating where we live in Western NY. Most customers use air very rarely Mabye 20-30 Days a year. So I use SH to charge. I am just trying to verify that I am doing it correctly.. I am one to think that the manual, and the people who wrote it should know more than me. And when I do what it says it is wrong. Every time. Do you understand what I am saying. You say dont trust factory charge I can deal with that.. However if it is never right mabye I am doing somethign wrong.

[pliscon]

Jult

My ST is 44
EST is 64

What would you say my SH should be based on the charts you use and the info I have provided. Also do you think the a smaller oriface would be better or lower fan speed. The current fan speed is high. I cannot hardly feel it coming out of the registers at the far end of the home.

[prodiyer]

Txv's should be standard. Your scale, gauges and themp probes could all be off. I dont know what other advice I can give you. Pull a vacuum, crack it loose and then charge by superheat.

[pliscon]

Originally posted by prodiyer
Txv's should be standard. Your scale, gauges and themp probes could all be off. I dont know what other advice I can give you. Pull a vacuum, crack it loose and then charge by superheat.

Yeah This is what I do sometimes. However I am constantly told by so called experts that you need to do what the manual says. From my experiences I think that is crap. I am trying to learn you have to understand this. I question why every time the manual is wrong. If I pull a vac and let it rip it is usually close within 4-8oz based on my chart and the Desired SH for conditions. What I question is am I not doing it correctly because when I do it this way it is so different than the way the manual tells you. My competition does not even do this it is pretty sorry situation where we live. What Oem chart do you use? or do you have a universal one. It seems they would all be similiar with like freons doesnt it.

[pliscon]

How do you charge with TXV? Subcooling? What is the desired Figure or does it change with conditions as well. Do I need a chart for this or is there a standard subcooling value to shoot for?

[prodiyer]

I dont use anything. Im just a homeowner that is learning from this site. I belieave the units will give you the required subcooling on the nameplate. Good Luck

[pliscon]

Yeah Ok Prod... Me too. The subcooling value is not on the nameplate either..

[pliscon]

Hey Jult are you still around

[duc dowg]

do you have a epa lic