Sewer backup into heating floor duct

[perriboni]

Last year I read your response to a member about cleaning floor ducts throughout. Can you reiterate how the sheet metal is easily damaged by the equipment used by the duct cleaning companies and that it is best to gently clean yourself by using damp towels etc. What are the companies using that will damage the sheet metal? I'd also like to know how best to deal with the effected crossover and ducts by the backup; clean or replace? Once the dried debris from the sewer backup gets into the furnace, what is the best solution; clean or replace? For the DIY, how do you clean the furnace from microscopic contamination? Thanks.

[hvac1000]

If this was a black water backup that got into the duct it is going to be a major problem. Black water is the stuff that flushes down the toilet. Grey water is washing machines,showers, and kitchen sinks etc.

I would never trust a cleaning of black water from the HVAC ducts. Remember all the air for heat and cool flows in this duct and any bit of bacteria left can cause a problem with your breathing and infections of the lung.

Most of the duct in our homes is made of aluminum or very thin steel. It is not very strong so as to take a major cleaning and you will be hard pressed to gain complete access to all of it for cleaning purposes.

Next if the backup got into the duct it is probably in the insulation around the duct. Someone is going to have to open up the belly of the home and do a real check on this situation. The insulation if wet or damp from the overflow will also have to be replaced.

This is a major health issue and the repair should not be second guessed.

Same situation for the furnace/A coil. I really doubt if the furnace was involved because a standard furnace is usually elevated with the A coil under it. Now depending upon the situation the coil could be professionally removed for access and cleaned properly.

[perriboni]

I think all of this information will be helpful to others. The backup was from the washer, 2 full capacity loads. After the water cleanup only I had a moisture test done that came back, no moisture detected. I had a Coliform/Total Fecal Test that came back negative. I had an Air Quality Test done that came back positive for debris, no mold. Which is from the roots that had blocked the sewer line. Also, when the company came out to clear the line, they got the snake caught. The sewer line was replaced.

In the mean time, I started cleaning the heating vent ducts with the method you recommended as I didn't want to take any chances damaging the 2 layers of 24 gauge sheet metal used to make the trunks. The job was tedious and the garden hose with sponges attached method was cumbersome but worked. I also found a child's sponge mop with a 3' handle at Toys R Us that fit perfect. That item is discontinued. Then I found a product at the local hardware store that is designed to clean the dryer dust duct. I only used the extension rods and ingeniously attached small replacement sponges used for another product. Again the job was very time consuming but worked. I found huge screws protruding into the ducts that blocked and or tore up the sponges though.

I couldn't finish the job before winter so I had to turn on the furnace and that's when debris came flying through the vents causing a severe allergy problem.

This is the contamination I am referring to. Can I clean the furnace or does the microscopic debris simply pass through and settle somewhere else that I need to clean? Or filter replacement is all that's needed?

Also, I'm not finding the underbelly wrap that covers the insulation. What does it look like and do I really need it?

The job still isn't fully completed. The crossover still needs to be dealt with. I retrieved the instructions that were posted previously for replacement but could I try to clean that too?

Thank you

[Robert]

Hi,

I would have the furnace inspected by a Tech to see what needs to be done and to what extent.

The underbelly is under the home. Under your home floor is the duct main trunkline, water lines, electrical, insulation and then below it all is the underbelly.

It will be a black plastic tarp like material slightly hanging down or could be a board type material (buffalo board) or may be something someone has placed there to make do.

Yes it is needed to keep moisture and critters/rodents away and to hold the insulation up.

The material is impregnated to resist rodents and insects.


Most crossovers are simply flex duct and it cannot be cleaned.

Best to replace with all metal duct and two 90* elbows or the two 90* elbows and flex duct stretched tight between them.


Take care and best wishes,
Robert