What is wrong with my furnace if water is leaking?

Correct me if I'm wrong , but isn't the XL80 an 80% efficiency gas powered, forced air furnace? If that is true, there should be no water coming from anywhere unless rain is coming in the chimney. An 80%er isn't a condensing furnace, so its not condensate. Are there other utilities like a water heater or tank that are in the same vicinity? That is much more likely. XL80 Trane

There are several questions that need to be answered about what type of system you have, but i found this posting that may help:
As your gas furnace runs, is there water leaking at the base? Is the furnace's air filter wet, too?There are a few things that could be happening here. But if you have a high-efficiency furnace, here's the most common cause: a condensation leak.
We'll explain why a furnace creates condensation, and what's causing it to leak out of your furnace.
Note: You'll know if you have a high-efficiency furnace if:

• The yellow energy guide tag says your furnace's efficiency is 90% or higher AFUE.
• The vent/flue pipe is white PVC as opposed to metal.

Why a high-efficiency furnace creates condensation
How in the heck does a high efficiency furnace create condensation/water anyway?
It's all about how the furnace extracts heat from combustion gases.
A lower-efficiency furnace extracts some heat from combustion gases and then quickly vents them out the flue pipe.
But a high-efficiency furnace, to extract more heat, has 2 heat exchangers. These allow the furnace to extract heat from the gases for a longer period of time. This causes the combustion gases to cool and then condense.
That condensation then exits out your home through a drain. But if that water is pooling around the furnace, there's a problem preventing it from draining properly.
Causes of a condensation leak around a high-efficiency furnace

• Clogged condensation tubing
• Clogged condensation drain
• Breaks in the condensation line
• Issues with the condensate pump (if you have one)

You'll need a furnace technician to diagnose which of these is the issue and then fix it.
Other causes of leaking water around a furnace
If you have a conventional, standard-efficiency furnace...then its flue pipe may be incorrectly sized.
If you have a whole-house humidifier connected to the furnace...there may be an issue which is causing the humidifier to leak into your furnace. Your humidifier should be getting annual maintenance from a professional to prevent this.

This furnace should condense, as long as it goes into the drain. If it is leaking inside the furnace, there may be a seal that needs replacing in either the pvc drain pipe or concentric drain trap needs resealed.

Water can leak from any furnace for a couple of different reasons.
If it is in AC mode, the AC evaporator could be freezing due to lack of refrigerant or airflow (check your furnace filter). Or the AC drain could be clogged normally a hose or PVC pipe coming from the evaporator.
If it is in heating mode could be high efficiency furnace not draining properly or leaking humidifier.

What type of fuel does your furnace burn?

Gas does condense more water when it fires, that oil--
and that condensing can be running out--- Usually that would be toward the discharge section of the furnace-- as the exhaust gasses might cool and condense upon leaving the furnace.

Or-- do you have a humidifier on the furnace--and maybe the little water sump is overflowing?

Be brave, and open a panel or two, and look around-- above the area the water is leaking out of-- what is in that area?

No. The installers did not properly plumb you hose. You have a high efficient furnace which is really nice. However, this furnace takes out moister from the air when heating, causing condensation. I would look at the installation manual and see if they installed them properly. They might of installed the wrong unit for you home. Most Goodman furnaces can only be installed up-flow meaning in the closet or horizontal installed meaning in the attic. Look at the installation manual to see if they installed the right unit for your home. www.fastacservice.com

You probably have a 90+% efficient furnace. They produce condensation. Does it have PVC vent pipes? If so there is a drain tube for condensation.

Yes you can use regular pvc glue. You should use pvc primer before you glue it.

Check the drain tubes inside the furnace. There may be a loose connection or a split tube.
The unit could also leak from the gasket between the secondary heat exchanger and the vent fan housing. The secondary heat exchanger ould also be leaking or cracked.
Hope this helps.
Matt

1.check filter if really dirty change
2. check Refrigerant if low get charged by a tech
3. check the evaporator coil if dirty clean