You’d have assumed I shot the guy’s dog! Man he was ticked off at me and all this over a missing component in his HVAC system that I had detailed in my inspection report for the pending sale of their home. By way of background, the owner is an engineer for a major manufacturer of HVAC equipment and he’s being relocated by the company. The HVAC equipment in his home was made by the company he works for.
The missing component? A condensate trap on his AC coil’s drain line! The condensate held back left a telltale trickle of water escaping at a seam in the coil box and there was evidence on the concrete floor that this had gone on for a long time. An internal view using our Ridgid inspection camera revealed no damage. I let him rage on for what felt like 20-minutes and once he calmed down, I suggested he allow me to e-mail him a scan of the instructions where his company’s literature, specific to his model, clearly spells out the required condensate trap — with an illustration. All this over a simple trap that would cost him just a few dollars if he was willing to install a PVC trap himself.
Why is it so many installers of HVAC equipment ignore the need to read the instructions, which have illustrations, and while installing a multi-thousand-dollar HVAC system decide to skimp on a part that can be had for less than $5.00 (PVC) or $20.00 for a see-through trap with easy access caps and an attached cleaning brush.
Why is it so many installers of HVAC equipment ignore the need to read the instructions, which have illustrations.
For a few dollars more, the clear see-through traps are available with an electronic safety-switch that can disable the AC should the drain become clogged. Personally, I like the see-through traps because it’s easy to get homeowners to maintain them by popping the cap(s), running the brush through the trap to dislodge debris/sludge, and flush the trap with some clean water. What has traditionally been the most ignored component suddenly becomes well maintained. I can tell you from experience: homeowners appreciate the ability to do this bit of preventative maintenance.
Pet peeve No. 2: Cutting corners by drilling a hole in the concrete floor for a ¾-in. PVC condensate drain. This is often compounded by tying the acidic condensate drain from the condensing furnace into the same AC drain. If you have ever responded to one of the festering clogged bacterial slime sumps, you know this is not a good thing to foist upon a customer.
When the AC condensate cannot drain freely, it can back up into the outlet from the heat exchanger. In my area of Pennsylvania, we have zones with very high levels of radon. You don’t need to be a rocket scientist to know drilling a hole in the floor and sticking a loose-fitting open conduit to the home’s ductwork is bad science. How bad depends on which side of the blower the AC coil is located.
If air is being drawn through the coil (suction side of the blower) and absent a condensate trap, or one that has lost its water-seal, radon and other contaminates will be forcibly drawn into the air-stream and distributed to the conditioned areas within the building. The condensate collection pan will most likely overflow due to drain-line air being drawn into the coil or the inrushing air will cause water droplets to be rejected into the passing air-stream, which will saturate the insulation lining. Premature failure of the internal rusting components beyond the coil is ensured, but this also sets up a fairly perfect environment to grow all sorts of bacteria and/or mold. (An AC coil installed on the return-air side of a furnace will cause condensation to collect on the heat exchanger and lead to early failure.)
If the coil resides on the outlet side of the blower (push through), then the coil box is positively pressurized and the potential to literally blow Btus out through the drain without a trap is likely. Radon and other contaminates can easily escape around the perimeter of the concrete floor’s hole. The venturi affect of air rushing over the gutter-like condensate collection trough at the base of the coil can actually create a negative pressure zone that will draw the radon and contaminates from under the basement floor. Been there — seen that.
A self-contained condensate pump is an easy fast fix with the discharge tubing directed to a plumbing code compliant safe-waste like the clothes washer standpipe. A bit of patching cement or silicone sealant will close off that radon/contaminate source, but first have a look at the snot-slime and pour a bit of bleach into that sump.
If the furnace is a high-efficiency condensing model, and your area experiences freezing weather, do not pipe the condensate pump’s discharge to the exterior, which will cause an embarrassing call-back to remove the ice-plug: re-pipe. Don’t ask me why I know this! As they say, experience is the best teacher.
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