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  1. #27
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,301
    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.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  2. #28
    Join Date
    Jul 2005
    Posts
    28
    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.



  3. #29
    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!

  4. #30
    I gave you very good advice on not trusting the manufactures charge and you blew it off.

  5. #31
    Join Date
    Jul 2005
    Posts
    28
    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..

  6. #32
    Join Date
    Jul 2005
    Posts
    28
    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.


  7. #33
    Join Date
    Jul 2005
    Posts
    28
    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.



  8. #34
    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.

  9. #35
    Join Date
    Jul 2005
    Posts
    28
    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.

  10. #36
    Join Date
    Jul 2005
    Posts
    28
    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?

  11. #37
    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

  12. #38
    Join Date
    Jul 2005
    Posts
    28
    Yeah Ok Prod... Me too. The subcooling value is not on the nameplate either..

  13. #39
    Join Date
    Jul 2005
    Posts
    28
    Hey Jult are you still around

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