[Nickshu]

Ok guys need help with a strange problem in a rental property I own.

Property is a 2 bedroom townhouse build slab on grade (no basement or crawl space). Place was built in 2006.

About 2-3 weeks ago tenants came home from being gone for the weekend to find the main level wood floors popped up between the kitchen and closet that contains the HVAC unit and water heater (about 4 feet apart). Wood floors are on concrete slab.

Tenant (who is handy) noticed the HVAC unit was not draining at all (A/C running all the time, it's 95+ degrees typical Colorado front range summer).

HVAC guy (who I have used for a few years and seems sharp) checked everything out, cannot find a leak. Determines that for some strange reason the A/C is cooling normally but is not pulling humidity from the house. Ambient humidity in the main level is 55-60% which is crazy high for Colorado. He comes back again the next day, investigates further, cannot find a leak in the condensate drain, but notices it's also not generating anything to drain. He recommends we call a plumber.

Plumber comes (same deal, good guy I have used for a few years) and looks high and low, cannot find a leak. Points out that the inside HVAC unit is a Trane (replaced by previous owner) and the outside unit is a Rheem (which appears to be original/2006). His conclusion is the water (or high humidity) is due to the HVAC unit, but that there could also be a hidden pinhole water leak, such as underground drain pipe or sprinkler percolating up through the concrete slab, especially if it was not properly barriered when built.

I tell the plumber that my HVAC guy has gone through the unit and it's working fine, but he can't figure out why it's not condensating humidity in the house. Plumber recommends we call a Leak Detection specialist.

Leak detection specialist comes and does a 4 hour examination with cameras, pressure testing, and infrared. Charges $500 for the evaluation (which is fine with me) and determines there is no water leaking anywhere. His conclusion is the problem is that the HVAC unit is not pulling humidity out of the air.

Back to the HVAC guy who says he cannot find anything wrong with the HVAC unit. He has called his other HVAC guy buddies, as well as Trane, and says no one has ever heard of such a problem.

At this point I am thinking just replace the HVAC unit, inside and out, with new matching units and see what happens. Problem is that this is an expensive "trial".

For now I have a dehumidifier running in the space which is helping the wood floor start to lay down and has reduced the ambient humidity to around 35-40% which is what it is in my personal home w/ A/C running right now.

Sorry for the long saga, but can anyone in the braintrust help explain why an HVAC unit would not pull humidity out? My HVAC guy says it's working normally, shows a normal Delta-T (whatever that is) and is appropriately sized for the unit.

Thanks in advance for any suggestions before I spend $8000 on a new HVAC unit here that may or may not actually fix the problem.