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AIR CONDITIONING & HEAT PUMP SYSTEMS
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BLOWER DOORS & AIR INFILTRATION
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BLOWER FAN OPERATION & TESTING
BOOKSTORE - Air Conditioning "How To" Books
CAPACITORS for HARD STARTING MOTORS
CLEANING & Legionella BACTERIA
CHINESE DRYWALL HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
DEFINITION of HEATING & COOLING TERMS
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DIAGNOSTIC GUIDES A/C / HEAT PUMP
DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
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DUCTS, Asbestos Transite Pipe
DUST, HVAC CONTAMINATION STUDY
ELECTRIC MOTOR OVERLOAD RESET SWITCH
EVAPORATIVE COOLING SYSTEMS
FAN LIMIT SWITCH
FAN NOISES, HVAC
GAS EXPOSURE EFFECTS, TOXIC
GAS DETECTION INSTRUMENTS
HEAT LOSS (or GAIN) in buildings
HEAT LOSS (or GAIN) INDICATORS
HEAT LOSS R U & K VALUE CALCULATION
HEATING SMALL LOADS
INSPECTION CHECKLIST - OUTDOOR UNIT
INSPECTION LIMITATIONS, A/C SYSTEMS
LEED GREEN BUILDING CERTIFICATION
LOST COOLING CAPACITY
LOW VOLTAGE TRANSFORMER TEST
MOTOR OVERLOAD RESET SWITCH
MOLD in AIR HANDLERS & DUCT WORK
OPERATING COST, AIR CONDITIONER
OPERATING DEFECTS, AIR CONDITIONING
REPAIR GUIDES A/C / HEAT PUMP
REPAIR & DIAGNOSTIC FAQs for A/C
THERMOSTATS, HEATING / COOLING
THERMOSTATIC EXPANSION VALVES
WATER COOLED AIR CONDITIONERS
WINDOW / WALL AIR CONDITIONERS
WINDOW / WALL A/C SUPPORTS
Air conditioner condensate pump guide: this air conditioning repair article discusses the inspection of air conditioning condensate pumps & condensate pump control systems, including their proper installation. This is part of our installation, inspection, & troubleshooting guide for condensate piping, traps, drains, condensate pumps, and the detection and hazards of air conditioning system condensate leaks in buildings.
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Air conditioner condensate pumps are a convenient way to collect and dispose of the condensate produced by an air conditioning system when the air handler/cooling coil are located in a building location where the cooling condensate cannot be drained away by gravity.
The most common situation is the need to dispose of air conditioner condensate produced by an air handler which is installed in a building basement or crawl space.
[Click to enlarge any image]
How an Air Conditioner Condensate Pump Works
Air conditioner condensate is water removed from the building air as that warm, moisture-containing air moves across the cooling coil in the building's air conditioning system's air handler or blower unit. The photograph shown here is of a common air conditioner condensate disposal pump.
It's a little hard to see the pump's drain tube but it's that clear plastic tube in the upper left of this photo. If you are really alert you may have noticed those two capped-off copper tubes protruding from the concrete floor in the foreground of this photo.
This pair of tubes is a convincing indication that there was an oil tank, probably a buried oil tank, installed at this property - a topic that needs further investigation. See Oil Tanks - The Oil Storage Tank Information Website, for details on that topic. Don't let our focus on any individual building concern make us miss another, possibly important discovery.
The air conditioner condensate pump photo at the very top of this page shows an air conditioning condensate pump installed in an attic where it was used to move condensate across to a final condensate disposal point.
The white piping is a gravity drain that moves condensate from the attic air conditioner air handler down into the condensate pump reservoir. We can't see much of the condensate reservoir because the installer placed this pump down into the attic floor (so that she could drain condensate into it by gravity).
The copper tube looping in the air is the drain line through which the condensate pump is moving condensate out of its reservoir to a disposal point. You can also see the black electrical wire bringing power to the condensate pump. The black round motor with a white label is the motor that powers the condensate pump.
The black rectangular device is a voltage transformer that converts the building's 120V to the voltage needed by the pump motor. In the background of this interesting photograph we see a blue sump pump with a green garden hose connected to it. We surmise that the owner had previously tried to use this sump pump to remove condensate from the attic air handler. Stains suggest that the attic floor has previously been wet by air conditioner condensate spillage, perhaps leading to the more careful condensate pump installation shown here.
Sequence of Steps in the Operation of an Air Conditioner Condensate Pump
Proper and Improper Places to Route and Connect an Air Conditioner Condensate Pump Drain Line
Here is an excerpt from the Uniform Mechanical Code pertaining to the disposal of air conditioning condensate: "Section 310.0, 310.1 Condensate Disposal.
To clarify, an indirect waste pipe is something that is upstream of a trap. That means we cannot dump into anything downstream of a trap. That would include the main plumbing vent stack - a common error in disposing of air conditioner condensate in attic installations. -- [Thanks to Al Carson, Carson Dunlop Associates, Toronto]
Acceptable methods to dispose of air conditioning condensate from a condensate pump
Air conditioning condensate drain connections which are not recommended or are not best practice
- Yaga 8/13/11
Yaga additional risks from condensate leaks into a building when you bypass or "hot wire" the condensate overflow tray sensor switch are condensate leak overflow, building damage, and mold damage
What else goes wrong with air conditioning condensate pumps
In our experience these little devices are pretty reliable and useful. But a few things do go wrong, some more often than others.
Continue reading at CONDENSATE DRAINS or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs) About How to Install, Diagnose, & Repair an Air Conditioner or Heat Pump Condensate Drain Pump
Question: Requirement for a trap on condensate drain lines; leaks led to ceiling fan collapse
As a homeowner I installed a condensate pump for my attic-located air conditioner as described above.
When my A/C tech inspected he said a horizontal flow air handler does not have a trap on the condensate output so air is drawn in through the air gap at the pump collection tank. This air flow keeps the condensate from flowing out the drain until the air handler blower shuts off, creating a tidal wave of water which sloshes where its not supposed to including the emergency drain pan. (My ceiling has fallen in 3 times due to overflowing emergency pan which did not drain properly.) - Bob Farrell 06/09/11
Question: The GFCI Receptacle that powers the condensate pump keeps tripping off - is a GFI required?
Frequent tripping GFI receptacle to condensate pump - Larry B 8/7/11
Does a condensate pump need to have a a GFCI receptacle - Bill Hastings 8/22/11
Reply: how to fix nuisance tripping of a GFCI in a damp area, basement, crawl space, etc.
Larry if the GFCI receptacle powering your condensate pump keeps tripping
Bill, the requirement for a GFCI receptacle for a condensate pump would come from where the electrical receptacle is located. For example electrical codes want GFCI protection in garages and perhaps in basements and crawl areas.
Question: what is the "overflow" box connected to my condensate pump reservoir?
Hi I have a reservoir with a condensate pump in it~ also there is another pvc pipe coming out of the other end of reservoir going up to a box that says overflow. For the first time water came out and on to the floor? any ideas? thanks! Archie 06/02/12
Archie, if that "box that says overflow" is under your A/C or heat pump unit it may be that the main condensate drain line is clogged so condensate is spilling into an overflow pan rather than being routed normally to the condensate pump.
breaker, fire o matic?, emergency switch all fine, but condensate pump outlet & ac unit will not work - Will 8/1/2012
Will, do you mean that the condensate pump outlet is wired off of air handler circuit or out of a service or utility receptacle that is powered by the air conditioner's own power circuit?
For detailed steps in diagnosing the reason why your air conditioner is not working, start at DIAGNOSTIC GUIDES A/C / HEAT PUMP.
Question: code citation for A/C condensate pump systems
(Aug 2, 2012) Matt said:
I have a primary condensate line going into a condensate pump then pumps into a plumbing vent. There is no p-trap between the pump and the unit. Is this code? I do understand the gasses could enter through a dry pump (I think that's possible in a dry pump). It is important for me to find out what the code reads as I can't find it anywhere.
A condensate drain shall be trapped according to the equipment or manufacturers specification.
Question: condensate pump won't shut off
(Aug 5, 2012) charles mc said:
My pump will not shut off. Even though my float is in shut off position, the motor will not turn off !! I cleaned the enter pump and the results are still the same..
It sounds as if your condensate pump switch is bad. The switch on some units is a replaceable part - but if yours isn't, you'll just want to replace the whole unit.
Question: additives for air conditioning or heat pump condensate pump reservoir
(Aug 7, 2012) David Lee Froehle said:
Is there an additive you can put in your condensate reservoir to cut down on the sludge created from the cooling process? It’s plugging up my drain line with a brown slime ( sludge). My furnace and air condition have both been replaced in the last five years.
(Aug 7, 2012) DanJoeFriedman (mod) said:
If the sludge crud is largely comprised of airborne dust (fabric fibers, skin cells) then a additive won't help but good air filtration will.
If the sludge is due to algal growth, the pan needs to be cleaned. I don't see how an additive would help because once added it would just flow out with the condensate.
Question: where to buy repair parts for air conditioner condensate pump
(July 13, 2014) Dee said:
I have a VCMA-20ULS condensate pump that works fine. However, the tank itself is cracked and is leaking. Where can I buy just the tank?
The condensate pump you cite is a Little Giant product (Franklin Electric) and is widely sold. But to by just a replacement part most likely you'll need to contact either an HVAC supplier or the company itself.
Question: what to do about condensate remaining in the condensate pump discharge tube
7/30/14 Jim said:
I just installed a new condenser pump n basement, all works fine as far as draining goes. However, my question is, although the water in the reservoir tank is properly removed, I can see water in the clear removal tube, is that normal? Shouldn't there be no water left in the tube itself after it pumped water out of the unit?
Yeah Jim I too find the water remaining in the condensate tube ugly, sometimes nasty. But it's pretty normal. The pump assembly forms a check valve on the condensate pump end of the tubing so no water should be back-draining from the tubing.
On a separate warning topic, I'd pay attention to crimps and kinks that can block the tubing - and often go unattended until the pump overflows.
Questions & answers or comments about the installation, inspection, troubleshooting & repair of air conditioner condensate pump systems used to remove HVACR condensate.
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