You walk down the basement to do a load of laundry and as you are walking past the furnace when something catches your eye. Is that a puddle of water on the floor right at the bottom of the furnace?! Where is that water coming from? Why is there water there? How much is this going to cost me? Am I going to need a new furnace? These are all questions that race through your mind in a split second. Take a deep breath, grab a few towels and let us help you answer all these questions.

Where is the water coming from

After you clean up all that water, you need to find out where the water is coming from. With high-efficiency furnaces, there are quite a few locations for water leaks. Lets’ go over a few of the most probable.

Clogged condensate drain and/or trap

These traps need to be removed and flushed as part of routine maintenance. When that gets clogged up and can’t drain properly, water will back up and flow out of hose connections, inducer housings, collector boxes and cause damage. Many times the hoses from these traps become loose, especially if not clamped down or even fall off completely and will cause water to leak all over. Simply, turn the power to the furnace off and remove the trap and hose connections to flush and run water through the openings. (shown in the photo above) Before you reinstall it, blow air through the main drain line to be sure it is clear. 

Another common cause for a leak is a clogged condensate drain. If you have a long PVC drain that runs across the floor, along the wall, and drains into a laundry drain,(photo above) there is a good chance that this can become clogged. I recommend replacing these long drains with a condensate pump to avoid this issue, but you can help keep them from clogging by adding a little bleach to the clean-out opening at the furnace every spring and fall.

Inducer housing

This location is common when the gasket between the collector box and inducer mounting point becomes dry-rotted and degraded.(shown in the photo above) You will know that this is the case by noting where the watermarks are coming from as well as the puddle underneath the inducer. To fix this leak you will need some high temp silicone sealant. Turn the power off to the furnace and remove the inducer. Dry up the area under the inducer and remove the rotted gasket. Add the high temp silicone in place of that gasket for a temporary fix while you wait for the replacement gasket which you should order for a permanent fix. 

Collector box

The collector box is where the condensation from the furnace heat exchanger is collected and distributed to the drain lines, trap, and main drain. The inducer will be mounted directly to this part and like inducers, they contain a gasket or silicone sealant which will deteriorate over time. You need to be careful here because you will also need to remove the inducer to get to this part and replace that gasket as well. You may also have a crack in the collector box too, which would mean replacement. The good news is that they are relatively cheap and come with new gaskets for the inducer and the collector box when you order a replacement (shown in the photo above). 

A leak here can be determined by following the watermarks. You need to be carefully determining this leak because it will look very similar to a leaking inducer, but the watermark will be only under the collector box and a leaking inducer will show a watermark on the collector box itself from the inducer mating point.

Finally, check all your hose connections and clamps to be sure they are all tight and secure. Always be sure to turn the power off to any appliance before working on it and be sure you don’t bump or knock loose, any other connections when performing any repair or maintenance. If you are unsure of any issue or your abilities, always consult with a professional, like our experts at fixmyfurnace.com.

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