Furnace dated 1977 A-coil dated 2010 A/C unit dated 2001. I noted two dryers installed on the liquid refrigerant line one at the A-coil and one at the outside unit which alerted me to the fact someone had no clue what they were doing.
I felt the supply air at the register with me old crusty hand and it did not feel cold as I would have expected with the outside ambient being only 85 degrees.
Normally I would have stopped operation at that point and just called the unit out as not cooling properly. Old stubborn me I go for my gauges just to make sure, I do not want some clueless contractor coming up with some off the wall statement
Obviously this A/C unit was haveing a low pressure problem as indicated by the gauges what would have been the next visual indication of a problem for those that can not use gauges on a unit.
My next question is how long do you contuine to operate a unit that you suspect is having a problem before you the inspector becomes part of the problem.
Answer these two questions and then I have more for ya. My pics poses many questions that no one is asking???
OK Charley out of 96 people viewing and no tries here goes, I have been told by a hvac mechanic that if the metering device has been changed a unit that was designed for R22 can also operate on 410-A. I see mixed units before. I would say this unit has different refrigerant types , two dryers , or it could be low on refrigerant.
The saturation temperature of R-22 refrigerant at 30 PSI is 8°F. If you have a restriction with a fully charged system there should be some cold pipe somewhere after the restriction.
Highside refrigeration pressure is equal to the outside air temperature.
High head pressure with low back pressure indicates a refrigeration restriction. Not indicated here.
Restricted airflow will also drop back and head pressures proportionately.
The coil was fairly new all good well maintained return air filters in use so that eleminates the air flow you were thinking about.
I did not operate the unit very long when I saw the 30 PSI suction pressure did not need to. There was no frost visible anywhere but If I had contuined to operate it would have had frost on the evaporator and the suction line back toward the compressor.
If the 2 dryers had been restricted there would have been frost or a real cool liquid line on the outlet side of the dryer neither of these conditions was present.
That leaves the high possibility that the dude installing the new A-Coil left a small leak when installing and it may have been intentional so he could come back and add more Freon in the years to come.
Keep in mind the problems with this unit were mainley visible to the inspector with the exception of the gauges if one knows what to look for.
If I had been trouble shooting this unit as a repair person I would have immediately looked for a refrigerant leak at the A-coil, based on its 2010 age
For those of you that say “I have no gauges”, there is a way to evaluate all of this without them during the course of a building inspection. To find out more, contact Dale Duffy. His commercial building inspection course will cover this and other methods of inspecting HVAC equipment.
Charley can just “lay hands” on that equipment and tell you what’s going on, don’t need no newfangled contraptions!
I think I should clearify something here about the two dryers installed on the liquid line.
The real problem with the unit was a lack of freon not the two dryers in series. Very doubtful the series dryers would creat frost on the A-coil.
I placed the pic of the dryers in this post to make the thread thought provactive.
The series dryers were called out in my report simply because if the MFG thought it necessary to have two dryers installed it would be in the installation booklet and it is not
