Hi --

Our 15 year old Goodman furnace went out a couple of days ago. The igniter would light but then cycle off quickly with no gas being fired. There was also a small bit of water at the base of the furnace. When I took off the top panel, I saw a little bit of water having pooled on the shelf where the electrodes/wires plug in ... and a bit more water at the bottom of the top panel/compartment. A bead of water was present on the fan motor assembly. There is no water source nearby that would explain the presence of water. HVAC technician came today and identified the gas valve as not working. He examined the chimney and said the cap and liner are in great shape. A bit stumped as to where the water came from ... curious if others have thoughts. Condensation in the flue pipe would be the best guess but there was no obvious signs of it (admittedly, it's cold and dry and the water that had been present had already dried up by the time he came). Might the faulty gas valve contribute to/cause condensation?

TIA for your helpful comments/advice/suggestions,
T

 

With no pictures, model information or where your furnace is located it is hard to offer specific answers. You are correct, condensation is a possible source.

 

Thank you. Home is located in northern Virginia. Furnace is in the basement. Two above ground floors above basement. Unit is Goodman GMS80703ANBC. Pics below. Thanks again!


Unit

Water at bottom of upper panel.

Water on shelf of upper panel.

Water bead on fan/motor

 

Is that an a/c evaporator or heat pump indoor unit on top of the furnace? If yes, this could be the source of water when in a/c mode.

 

I think that is "new" water. If it were something that has been happening for years there would be a definite rust and dirt spot where the water collects. I would check to see if something in the condensate system has clogged. Make sure the catch pan drain is clear as well as the pipe leading to the condensate pump. Also check the pump. The pump and float tend to clog up with snot if not cleaned every year or two.

 

It looks there has been water running all over that unit. I see many places of corrosion.
The top of the blower door has seen a lot of water.

If the water is coming out of the bottom of the draft inducer.... and it looks like it is..... it's condensation coming back down the exhaust system.

 

Hi --
Thanks for all of the helpful comments. That is the AC "unit" up top (apologies if I'm not using more precise/accurate vernacular). Will have the HVAC guy check for all the crud/buildup areas PilotDane mentions so that we can rule out something being backed up. On the condensation ... wondering if that had any impact on the gas valve going. Wouldn't thing so, but obviously far from an expert. There is a fairly long run for the exhaust pipe to the chimney and the angle, while within code ... is pretty gradual. Wondering if that contributes to a condensation issue.

 

If your furnace is severely under-fired, burning too little gas and running too cool, condensation can occur in the exhaust pipe and drip down.

The furnace install is horrid, especially the wrong width coil slapped right on top. They should have put a coil the width of the furnace or built a duct transition to go from the 14" to the 17" coil.

Those allergen filters in the picture are harmful to the furnace, plug up too fast and become super-restrictive to flow. Be careful with those, changing frequently and once they're done, switch to basic dust protection filters.

 

User 10 -- thank you for adding all that. Yeah, the install ... not great, but not the first surprise at this house.

On the filters -- how often would you suggest a change for these?

 

How often a filter needs changing depends on it's use. Check them periodically and determine how often you need to change yours.

The location of your return air intake makes a big difference. A intake located at or near the ceiling can go very long without a filter change while an intake low in the wall will need more frequent filter changes. Worst is a intake in the floor which could need changing in weeks. Things like pets and how often you vacuum also have a big affect on how much is floating around in your air.

In general a high efficiency filter may need changing more frequently. "Premium" filters start out with higher resistance to flow. Their fine pore size is great for catching small particles but it also means it can clog up faster. Traditional, cheap filters are much more porous and can go a long time between changes. Still, changing more often is better for air quality and to minimize flow resistance through your air handler.

 

Thanks again for all the help. So far, the gas valve was replaced but condensation continues and was definitely able to determine the flue as source. Flue does have a liner going all the way along the run and up through the chimney. Chimney cap is in good shape. Noting that I had formerly had a gas water heater, but it's now electric.

Wondering if maybe liner in flue is compromised? Trying to explore other solutions. Curious to hear any ideas. One HVAC guy said he can test how hot it's running and potentially increase it to minimize/eliminate condensation (if I understood correctly).