HVAC – Cleaning Your Condensate Drain

April 25, 2017

You probably read my article on “Is your Air Conditioner running Efficiently“, there are a lot of good tips in that post as we near the air conditioning season. In this post I want to highlight the condensate drain (another one of those items that gets little respect or notice until it’s not working properly).

Looking at the picture with the blue box knife you will see a piece of 3/4 copper with all but about 1/4 inch opening left. This is what I found today as I replaced a condensate drain. I would have never figured this!! As with many HVAC installations, units may be changed out every 10 years or so, but how often is the condensate drain replaced or inspected? Granted, this will not impede the unit from making cold air, but it may leave an ugly damp spot on the ceiling or floor (depending on the location of the HVAC).  As it can back up and overflow.


HOW DOES A CONDENSATE DRAIN WORK: Lets first start by understanding  what the condensate drain does. In the process of the cooling the house, the evaporator coil inside the air handler unit (located in a closet, attic or basement) operates at a temperature that creates condensation on the cooling coil. The collected water from this process  has to drain off. The water drips off the evaporator and is  expelled through a drain pipe. Based on gravity and slope, the water is either released outside the house or into the sanitary drain pipes. This drain tube must stay clean of debris, otherwise it can back up and cause water to drain into the house damaging sheetrock and possibly the building structure. They only drain when the unit is running in AC mode. Visually seeing water dripping is not a good enough inspection as it could still be backed up.


Visually inspect the condensate drain for all the parts mentioned in this picture. Pouring a vinegar in the VENT and the pan will allow you to look for leaks and the rate of flow. Both locations should drain in a few seconds.

  • VENT: Should be open and clear.
  • PAN DRAIN: Should be open and clear. Should exit out of the house where visible. If you see water dripping from this drain pipe (at its exit), the primary condensate drain is probably stopped up.
  • DRAIN PAN: Resides under the HVAC unit and should be clear of debris and free of water. Rusted pans should be replaced. Collected water in this pan is an indication there may be a drain flow stoppage of the primary drain.
  • PRIMARY & PAN DRAIN: Both should have a slight downward slope to its destination. This will ensure the water can flow freely out of the house.

HOW TO CLEAN A CONDENSATE DRAIN: If the drain has never been cleaned, it would be best to use a Wet/Dry vacuum cleaner to attach to the pipe (at the end, outside the house) to suck out all the debris. Seal the vacuum cleaner hose to the drain pipe (furthest from the HVAC). Run the vacuum for about 5-10 minutes. In really bad cases, you may need to pour some vinegar down the drain to pull the gunk through the pipe while the vacuum is running. If necessary, you may need to repeat it until it shows to be running free and clear.Once you know it is clear pour a a gallon of vinegar down the drain once a year. That should keep it in good shape.


Is Your Air Conditioner Running Efficiently?

August 11, 2015

AC unit Here in the Southwestern part of the country air conditioning is a requirement. With temperatures running above 100 degree’s for weeks at a time, these systems can struggle to perform as necessary to keep you and your family cool. Besides filters, there are a few other things that are worth mentioning. If you think you may have a problem, it will probably be showing up in your electric bill as either you or your system is having to compensate for its inability to perform as required.  Canvas your neighbors about their electricity usage as a comparison. Talk to folks that have simular houses and life styles for a good comparison. Square footage, thermostat settings and occupancy times are all important. Differences of more than 20% can be a clue there may be an issue. Also, use energy numbers or kwh as listed on the electric bill not the actual dollars spent. Here in Texas, the electricity is deregulated and there could be 2 to 5 cents of difference in kwh per hour charges.

If your system has operated properly in the past, these inspection and preventative maintenance items will ensure optium performance.  However, if your system has never worked properly or struggeled to keep the house cool, you may have design or service conditions that may warrant a call to a professional. Either way, by inspecting and maintaining the obvious you are  isolating the issue allowing the trained technician more time to fix the problem less time to find it.

Inspection and Maintenance Items:

  • Clean air filters: Replace the air filter 2 to 4 times a year. See my complete article for details.  Heating/Cooling Air Filters.
  • Air Returns:Keep these vents clean from dust debris and any obstruction. Depending on the design, the return air vent(s) may be close to the floor or in the ceiling. If the air return is near the floor, remove the metal grid and use a vacuum cleaner to remove all the dust and debris. If you have an air filter located here, replace it as necessary. In some cases you may have a filter here as well as at the unit. If so, this filter should be replaced on the same schedule as your normal filter.
  • Room Temperature: A well designed central air conditioning system should provide balanced air flow and temperatures of no more than about 3 degrees in difference from one room to the next. Large windows and doors will impact that number to some degree.
  • Air Flow: With air registers in each room, the air must circulate from the room to the return air location. For this reason, the air must be able to exit the room with the door closed. Either the door will (should) be undercut or there may be a pass-through return vent into a hallway or another room. If doors slam themselves shut (when the system is running), you may have a return air issue. TIP: If you recently added new carpet to your house, and you are now having air conditioning problems, the new carpet may not be adequately allowing the air to return under the doors. 
  • System Temperature Differential: This test is similar to checking your blood pressure as variables can effect the results. Most professionals set the thermostat low enough to require the system to run constantly (8 to 10 degrees below ambient) for at least 30 minutes (run it longer if you can). Use a digital thermostat to validate the air temperature exiting the register. Do not go by the temperature of the register itself. Its the air temperature you need. Do the same at the make-up or input air. You should have a temperature differential of 14 to 20 degrees in difference.   Too high or too low is a symptom of a larger problem. High numbers indicates a 1) dirty filter, 2) improper/inadequate duct-work, 3) a fan not spinning fast enough or undersized.  A low number indicates 1) refrigerant loss, 2) a dirty coil, 3) overworked compressor, 4)over-sized fan, or 5) deficient/blocked  return air system. Check the obvious, then contact an HVAC specialist.
  • HVAC drainWater Pan and Condensate Drains: In the process of the cooling the house, the evaporator coil inside the air handler unit (located in a closet, attic or basement) can pull humidity out of the house envelope. In doing so, that water collected by the system has to be expelled. By design, a drain is connected to the unit and released outside. This drain tube must stay clean of debris, otherwise it can back up and cause water to drain into the house causing damage to Sheetrock and overtime to the building structure. They don’t drain all the time so just visually seeing water dripping is not a good enough inspection. Once you locate the drain, use a Wet/Dry vacuum cleaner to attach to the pipe (at the end, outside the house). Seal it as best as possible and run the vacuum for a couple of minutes. This should pull any bugs, lint, dust or debris out of the pipe. This is a better method than pouring water through the system, and a lot less messy. Perform this function at least once a year.
  • Outdoor Compressor: Ensure plant material is clear of the compressor (18″ to 2′), remove leaves, grass, vines by hand. Use your water hose to spray down the coils to remove lint dust and dirt. This is probably one of the most important quick solution to a system that is under performing.
  • 100_0529Outdoor Compressor Connections: There should be two copper pipes and one maybe two electrical conduits. The larger of the two (suction pipe) copper pipes  should be properly insulated (all the way to the air handler/evaporator coils in the house. This pipe is delivering the cold freon used to cool the house. The longer it can stay cold, the better. Also look at the electrical connections to ensure they are sealed (sealtite  type conduit) and secure. There will also be a small low voltage wire  that may or may not be in a conduit, make sure it is not cut chafed or deteriorated.
  • Air Ducts: This item deserves an article on its own. Independent studies have shown up to 35% loss in cooling capacity due to poor duct insulation, leaky ducts, leaking air vents and duct splicing.  Inspect for air leaks  throughout the entire system. All of these components that make up the delivery system should be sealed with the highest degree.  Use Aluminum faced tape or mastic paint rated for UL 181 applications to seal any holes. DO NOT USE FABRIC BASED “DUCT” TAPE. TIP: If you are considering replacing your HVAC system look seriously at replacing the duct work as well. Poorly insulated ducts can reduce your SEER rating by 50%.
  • Set Back Thermostat: If you don’t have one, you need one. This is one of the most effective ways in managing your heating and air conditioning requirements and costs. Basically, you program it to change the temperature automatically to meet your lifestyle needs by adjusting the temperature for periods when the house is not occupied. Regarding the maintenance? Most are battery equipped and you should change it once a year.
  • Attic Insulation: Inadequate attic insulation can also effect the performance of your system. Use this US Gov link to determine if you have enough insulation for your region. Use a straight edge or yard stick to measure the insulation in various places. Avoid compacting it or stepping on it any more than you have to. Use a rake to re-spread and  fluff the insulation.

Key Inspection Points Action Items:

  1. Replace air filters
  2. Inspect and clean all air grills
  3. Clean and inspect outdoor compressor unit
  4. Clean condensate drain
  5. Inspect ducts for leaks
  6. Change battery in thermostat
  7. Check level of attic insulation

Re Insulating HVAC Ducts

December 1, 2009

The US EPA reports leaking ducts reduce overall HVAC efficiency by 20% accounting for a loss of over $140 per year due to these leaks.

 As mentioned in earlier articles, HVAC ductwork has not received the attention it deserves. Take a look at  my HVAC Duct article to evaluate and inspect your existing duct work. If you have determined that it is in need of attention you have three choices, 1) do nothing, 2) have them replaced or 3) re-insulate them.

  Duct Replacement: Be prepared, HVAC contractors typically want to sell new systems.  Here is the SW part of the US, their big season is the summer, having this done during the cooler months may be a better choice. Duct replacement is not as profitable as system replacements, but keeping their technicians busy can be better than not working them at all.

Considerations when discussing this issue with a HVAC professional:

  1. Flex ducting is a widely used proven product but does not have the long-term performance rating found with a typical sheet metal product. But is widely used in the residential market and most professionals like to use it because it is easy to install and not as labor intensive as rigid duct work. This product  can easily be mis-installed by creating kinks and  sharp bends that can reduce the product performance. Read this flexible duct inspection method before you meet with the contractor to better understand the product and how it is applied.
  2. After an evaluation, most HVAC specialists will want to replace the ducting in lieu of  repairing or re-insulating. Why? It’s quicker, cheaper and it becomes a known value. This is not a bad thing, these folks are trying to make a living and attacking the problem by replacing everything may be an economical solution for both of you.
  3. If you allow a professional to replace the ducts, make sure to ask some of these questions. Will all the joints and edges be sealed with (paint on) mastic? What is the R value of the new duct? What is the life expectancy of the duct product? What is the product warranty? What preventative measures are followed to avoid kinking (of the ducts). Will the system be tested for leaks after completion?
  4. If the professional didnt mention it,  also consider having all the output and return registers (this is the box in the wall/ceiling where the vent cover is attached) replaced or re-insulated. Most new registers are sealed and insulated to insure a tight fit. Also, ask them to use spray foam insulation between the register protrusion and the sheet rock, this will further seal the interior  from the attic space. Most HVAC professionals do not address register penetration into the interior space.
  5. If you have any rooms that never seem to adequately heat or cool, make sure and mention this to the professional too as he may have to resize or reroute the new duct work to better balance the system.

Duct Re-insulation (for rigid ductwork): This is a great DIY project if you consider yourself cheap labor and you dont mind working in the attic. Consider this a mult-weekend project. Before you start, ask yourself these questions. 

  1. Does your system work reasonably well? If you have any rooms or areas in the house that never properly heat or cool, consider adding an additional output duct as this would be the time to address it. Consider using a professional to perform this work as you may need to rebuild some of the system to retain the system balance.
  2. Is your attic adequately insulated? If not, plan to do it, but after all you other attic work is complete.

 The process if fairly straight forward and here is an outline of the necessary work.

  1. Strip the existing insulation material
  2. Ensure all joints are secure and snapped and screwed together
  3. Use duct mastic to seal ALL seams and joints
  4. Use HVAC tape to complete any seals not treatable with mastic
  5. Use expanding foam insulation to fill any cracks between the duct registers and the sheet rock
  6. Use duct wrap to re-cover all the exposed duct, seal with duct tape and mastic

Material Required for the Job

  1. Duct wrap rated at an R value based on your region (see table below)
  2. 1/4,1/2, and 3/4 self tapping sheet metal screws
  3. HVAC Duct Mastic
  4.  Take adequate precautions while working in the attic. Avoid stepping directly on the sheet rock ceiling and wear protective clothing and dust masks.
  5. If a professional indicates the duct are under/oversized, you may ask them to provide  the Man L or Man J duct analysis supporting their position. (This is an engineering schedule that is used to properly size ducting.)