Cold supply air

Yesterday, ambient air outside was 84 degrees, average return air temp was 71 degrees, nothing out of the ordinary… Average supply temp was 29-30 degrees. Never seen this low supply temp before. System had been running, occupied. I will refer out but what is the cause ?
4 ton, 2003 Lennox, 13 Seer.

You have a picture?

A pic of what ?

That’s a near impossibility!

The only way to get the refrigerant down to those temperatures is to lower the pressure. If you lower the pressure you reduce the capacity and it can’t cool the air that cold.

Where did you come up with those numbers?

Did you have any airflow?

If it that’s cold it should blowing frost and that would be a good picture. Now freezing happening across the coils should not translate into a below freezing temp at a register. However if the unit is bigger than it should be there could be an issue. Greg may need a new tester…

A Coil was clean, compressor was not froze up, normal air flow…

I knew you would have a picture

My dial temperature read average 30 degree supply, was stuck in the vent for maybe 30 minutes. Dial is so small does not make for a good pic…
Maybe Greg needs a new dial tester too ??

Trying to concentrate

Well, I guess if they put R-410a in an R-22 system at 70 psi they would get down that cold (19F)!

I think your battery is dead!

A unit that old uses R-22. You would have to get down to 42 PSI without starving the evaporator.

When your saturation temperature gets down to about 19°F you only have a very small section of the evaporator coil at that temperature and it would freeze.

How big was the house?

Was 24oo’

Greg, I just sent you a big @zz file. Enjoy!

Did ya think to look at the type of refrigerant in 2003 they were using refrigerant other than R-22 but there was still a lot of R-22 also. R-22 starts to form ice just below 55 PSIG

No tags or info on the unit but then again I have no business determining what type of coolant was used let alone hooking up any gauges for readings. Referred.

It would be right under:

I recommend that you start looking at the refrigerant type as the R-22 is being hacked by the govt. Your clients cost for repair will rise rapidly on this refrigerant and should not be repairing equipment they can’t get gas for.

It was in fact factory charged 410. If the system was good overall I would give notice but this system components condition were already being referred out anyway.

Thanks for that David…

I knew you had a good grip on the situation because that’s what you do. My man Greg!:mrgreen:

I was not implying to put gauges on a unit you were asking a question with no answer without more info,but most of us look at the data plate which list age, size tonnage, the breaker size, the refrigerant type and amp draw is also listed some even take a pic of the data plate. If no data plate you are just reduced to SWAG