Bob is a service technician who is well trained and nationally certified. However, he sometimes suffers from the same confusion that all technicians occasionally do - the facts that he gathers may or may not point to the obvious cause of the problem or the best solution. But Bob has something that no one else has. He recalls his long-time HVACR mentor and imagines him accompanying him as "Btu Buddy," someone who reminds him to take time to stop and think before rushing to judgment, helping keep him on the right track, even with facts that are confusing.

Bob receives a call from the dispatcher that the basement in a large home is flooded and the owner thinks it has something to do with the air conditioner. When Bob drives up in the driveway, the homeowner meets him at his truck and says, "There is a lot of water in the basement and it seems to be coming from the air handler that is located in a closet in the basement."

Bob has never done work for this customer, so he asks the owner to take him to the place where he thinks the water is coming from.

When they enter the basement, there is about 1/4 inch of water on the floor around the air handler and the adjoining room. The carpet is soaked. Bob tells the owner that the quicker he gets the water up, the better it will be. Bob recommends a carpet company with a large vacuum system to extract the water from the carpet.

Figure 1. This is a dry well. It is a hole filled with rock or gravel. The soil must be able to absorb the water or the well will eventually fill up. (Figures are from Refrigeration & Air Conditioning Technology, 5th Edition, by William Whitman, William Johnson, and John Tomczyk, published by Thomson Delmar Learning.)

The owner goes to contact the carpet company and Bob starts to search for the problem. What he finds confuses him. The condensate drain runs into the concrete floor in plastic pipe, but he doesn't know where it terminates. He is outside looking for where it drains into the yard and can't find any sign of the drain when Btu Buddy says, "It looks like there has been a lot of landscaping here recently. There are raised flowerbeds all around the house. That pipe could have terminated anywhere. Let's ask the owner if he may know where."

Bob asks the owner, "Have you ever noticed any water draining in the yard that may have come from the air conditioner?"

The owner says, "No, the yard has always been dry."

Btu Buddy then says, "I bet the drain line went to a dry well that is supposed to absorb the condensate water. (See Figure 1.) The dry well may be saturated or the landscape help may have dug it up and planted a tree in the hole."

Bob then asks, "Wouldn't they have said something to someone first?"

Btu Buddy responds, "Maybe not. They may have just assumed it was their job to grade the earth and plant."

Bob asks, "Now what?"

Figure 2. This condensate pump may be used to pump small amounts of water uphill to a drain location. It is great for basement locations where there is no drain.

Btu Buddy explains, "There is no good way to drain the condensate out by gravity. There should have been a floor drain installed here; instead, the water was carried out to the yard by gravity. Now it is uphill to anywhere from the drain on the evaporator coil. We must now consider a condensate pump to pump the water uphill to a termination point (Figure 2). Let's look around and see if there is a laundry room down here."

Bob looks and finds a laundry room down the hall.

Btu Buddy then suggests that he get the owner involved in the decision.

Bob explains the situation to the owner and shows him a picture of a condensate pump that has a float that starts the pump when the small reservoir is filled with water. He also explains that the pump has another feature that would shut the air conditioner off in case the primary float did not function. This would prevent the flooding problem from occurring. He also shows the owner how he would route the small plastic pipe from the condensate pump to the laundry room where it would terminate in the drain pipe for the washing machine.

The owner gives Bob permission to proceed. He then asks how much water a unit like this generates. Bob does some calculations and says, "A unit would normally generate about three pints per hour per ton of air conditioning. This is a two-ton unit, so that would be about six pints per running hour. The weather is very hot, so I would suspect the unit is running 20 out of 24 hours. That is 20 x 6 = 120 pints per 24 hours, which is 15 gallons (120 pints divided by 8 pints per gallon = 15 gallons). Fifteen gallons is a lot of water. This must have been stopped up for a few days."

The owner then says, "We often go several days without coming down here, so that explains why there was so much water."

Bob then says, "I am going to get on with installing the pump."

Before he leaves the job, Bob goes to the owner one more time and asks him to come and see the pump where Bob explains the installation.

The owner then says, "Thanks for taking care of the job for me. The carpet crew is about through. They have sucked up all of the water and are setting up fans to further dry the carpet. They suggested that we keep the air conditioning running to help remove the moisture."

As they are riding away, Btu Buddy says, "That job turned out well even though it started with so many problems."

"Thanks for the help," Bob says. "Another satisfied customer really helps."

Publication date: 08/21/2006