A new danger with dryer vents

20 Jan
It was just two litres of water but enough to completely block the dryer vent hose, creating a potentially dangerous situation. (Geoff Meeker photo)

It was just two litres of water but enough to completely block the dryer vent hose, creating a potentially dangerous situation. (Geoff Meeker photo)

January 20, 2014 – Just when you thought you were up on all the potentially life-threatening things that can go wrong with your clothes dryer, along comes a new wrinkle.

You know how important it is to keep the dryer’s outdoor exhaust vent clear of snow, the lint trap clean and otherwise ensure that hot air can exit the machine unencumbered. Otherwise, superheated air can build up inside the machine resulting in a house fire.

So, last week we noticed that the dryer was behaving oddly. It’s half of an energy-efficient, front-loading washer-dryer duo purchased two years ago so we weren’t expecting problems this soon.  But something was definitely amiss. Steam was condensing around the outside edge of the door and clothes were not drying. On opening the door, a cloud of hot steam smacked me in the face.

It was clear that air was not venting from the dryer. I checked the outdoor vent and it was all clear (there was snow on the ground, though none around the vent hood). I looked behind the dryer and everything appeared normal – the hose was properly connected and not pinched in any way.

We shut the dryer down and called the appliance repair people, who sent someone the next day.

He walked into the laundry room, I explained the problem and he smiled knowingly. To confirm his theory, he reached behind the dryer and jiggled the vent hose.

“I know what’s wrong,” he said. “Get a bucket and a towel. The hose is full of water. We’ll have this fixed in no time.”

What? Water? How could that be? However, my scepticism was promptly washed away when he loosened the hose on back of the dryer and drained about two litres of water into the bucket.

“How did that get in there?” I asked.

“It must have come in from outdoors,” he said. “We had heavy rain and high winds recently. Chances are it blew into the vent. Is there a hood covering the vent?”

Um. No. That was long gone, destroyed by numerous collisions with my lawn mower. The repairman smiled again, said this was definitely the problem – wind was blowing the trap door open, letting the weather in – adding that he sees this fairly often.

My dryer sits on a pedestal that raises the appliance more than a foot off the floor.

“Good thing you have that pedestal – and a fairly slack hose,” the repairman said. “It forced the water to collect at a bend in the pipe near the floor and lower than the back of your dryer. You don’t want water running into the appliance. That’s never a good thing.”

The good news was, the problem was easily fixed – I bought and installed a new vent hood later that same day – and there was no damage to the appliance. But I was one of the lucky ones: many houses are damaged or destroyed by fire – and lives sometimes lost – due to blocked dryer vents.

What should you do? To keep water out, check that your vent hood is intact and that the trap door lies shut.  Occasionally, lift the vent hose to test for water – if it’s there, you will feel the weight. At least once a year, remove the vent hose from the back of the dryer to remove lint build-up, because the lint trap doesn’t catch it all (there was a lot of lint in the water that came out of my vent pipe). And it goes without saying that you need to clean the lint trap between every load of laundry.

As a precaution, avoid starting the dryer before leaving the house or going to bed. You’ve got a 30 amp appliance with a heating element just inches away from flammable clothing, so perhaps it’s best to not leave it running untended.

Indoor venting?

While at the hardware store, I noticed a couple of indoor venting kits which promise to add “extra heat and humidity” to your home by releasing the exhaust directly into the house, through a little box with a filter. It sounds like a great idea but don’t fall for it – these things will pump an excessive amount of humidity into your house that will quickly cause mould and mildew, resulting in expensive remediation work. Furthermore, the lint trap in your dryer and the filter in this device cannot remove all lint, so it will circulate fine lint dust throughout your house.

The idea is sound but you need a way to remove humidity before recovering the heat. The only sensible way to do so would be connecting the dryer exhaust vent to the air-out duct on the air-to-heat exchanger. This way, heat would be reclaimed while steam is vented outdoors. However, even this method would result in a lot of condensation inside the unit so a robust drainage system would be needed.

Are any inventors out there up to the challenge?

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