Gut feeling

Sometimes I just get a gut feeling when some things just do not appear right.

I had numerous red flags waving before I turned the A/C unit on today.

The supply ducts embedded within the slab on grade foundation had one floor boot that had a water level mark and a lot of rust visible from the register. This boot was in a dining area straight in line with the plenum on this downflow furnaced. The remaining boots were completely dry and no rust.

The bottom of the A-coil box was rusted out at the bottom. This was a 1976 install. The humidity was very high today and the suction line should have been sweating to high heaven and it was not. The line felt just slightly cool to the hand.

I do not normally do any trouble shooting but my curiosity was just too high so I placed my gages on the unit and sure enough the suction pressure was only 40 PSIG. Should have been 65 or greater on a warm house.

I must now decide after going this far is it low on Freon or is the A-coil stopped up with lint creating this low pressure. I pop the cover on the A-coil and it is as clean as a baby’s Butt and the A-coil is sweating only on the bottom 1/2 of the coil. Got that solved low freon. The drain pan was also gone that was why the moisture in the floor boot, water filling up the bottom of the plenum and traveling down one duct.

Am I telling HI’S to do this NO this is just me. My way of protecting my client from some Jake Leg contractor from coming and just throwing a little freon in the unit collect his money and be on his way. I will spell out in my report just what is wrong and if the drain pan is not changed out the monkey will be off of my back. This all started with just a visual glance and a gut feeling.

Good job…sometimes I wish I knew what some of you specialists on this board know and then sometimes I’m glad I don’t. :wink: :smiley:

You don’t really want to know Larry It can be scary:)

in Sw Florida Where I Am A Inspector You Have To Have A Epa Certification To Even Touch An Air Conditioner. Inspectors In Florida Can Only Do A Temperature Split. The Temp Of The Air Going Into The System Vs The Air Coming Out. I Have Been A Certified Hvac Technician Since 1994. I Just Recently Became Certified As A Home Inspector, And Just Recently Became A Certified Mold Inspector. The Reason I Got These Certifications Was To Help Me In My A/c Business. In Florida You Can Get A Large Fine For Touching A/c Equipment With Out That Certification. So You Are Very Lucky You Don’t Have Those Requirements Were You Are

The same determination could have been assumed by the same process described, without the guages. I haven’t had certification for over 10 years, and don’t want it now. But in this situation, an experienced “feel” would have determined that, if the liquid line was on the high warm side, maybe, just maybe, the coil or restrictor is clogged. Of course, the language in the report should reflect that, saying something like “further analysis by a trained HVAC tech is recommended. Be sure your technician checks thoroughly for clogged (coil) (restrictor) or faulty expansion valve (if that’s what is present)…etc.” so that your client has a head’s up and can ask somewhat intelligent questions. On the other hand, if the liquid line were only slightly warm, as was probably the case above, you can pretty much assume low refrigerant…or an internal compressor problem.

Well thanks for the knowledge
Have been in the HVAC field since 1963 took the first EPA certification that was ever required. Hope you are a better HVAC than some of the younger ones I have been following around observing their work:D :smiley:

A properly charged air-conditioning system that has a blocked evaporator coil will not boil off the liquid refrigerant because it is not absorbing sufficient heat , due to the lack of air flow.

In this case the suction line will become extremely cold because the refrigeration effect is taking place in the suction line circuit, which ends with the compressor.

One observation you should note is that the suction line can be wet to the compressor but should not cause any condensation on the compressor. If you see a wet compressor, you should have the equipment serviced and then further evaluated.

You will generally find that the compressor is soaked with condensate and if this condition has been ongoing for a substantial period time the compressor may be totally rusted.

A blocked evaporator coil will cause low suction pressure (as posted). If there is a sufficient refrigerant charge, this low-pressure will cause the “extremely cold” temperatures at the suction line because refrigeration pressure and temperature are relative to one another.