Why Is My Water Heater Backdrafting?

I find a fair amount of water heaters in Minneapolis and Saint Paul that backdraft.   Backdrafting happens when the exhaust gases from a fuel-burning appliance,  such as a water heater, spill in to the room rather that rising up and out of the house through the vent.  This is a potential safety hazard that should always be repaired.

The most common question that I get when I find a backdrafting water heater is "How can this be fixed?"
There are many potentials reasons for a water heater backdrafting, but there are several basic things to check - any one of these conditions could be enough by itself to cause a water heater to backdraft.

A missing rain cap. Not only do rain caps help to prevent rain from dumping in to the vent, but they help to downdrafts; these are wind currents that can blow exhaust gases back down the vent.  A listed cap is also required by the Minnesota Fuel Gas Code, section 503.6.6.



A backpitched vent connector. A water heater vent connector, often called a 'flue', is required to pitch upwards towards the chimney or vent at a minimum slope of one quarter inch per foot (MFGC 503.10.8).  This is a minimumrequirement.  Just meeting this minimum requirement doesn't mean everything will work the way it's supposed to.  The steeper the pitch, the better the draft.



Insufficient combustion air. I start every home inspection the same way - I close up all of the windows and doors, and I turn on all of the 'motors' at the house that remove air.  These fans include bathroom exhaust fans, kitchen exhaust fans, and clothes dryers.  Besides giving me the opportunity to make sure the fans are properly working, I'm removing a lot of air from the house at one time, which creates a 'worst-case' scenario for the fuel-burning appliances, such as the water heater.  If there isn't a proper combustion air duct installed, the water heater vent may end up acting as an air intake. This will definitely cause backdrafting.

A vent connector located directly across from a fan. Most newer furnaces have an induced draft fan that is designed to pull the exhaust gases out of the heat exchanger.   This fan ends up 'pushing' the exhaust gases up the vent, and if the water heater vent connector is located directly across from where the exhaust gases are directed, the exhaust gases from the water heater get pushed right back down.  The water heater doesn't stand a chance of drafting properly with this configuration.


The water heater isn't venting in to a chimney liner. When a water heater vent connector enters a chimney separately from the furnace or boiler vent connector, there's a good chance that the vent just pokes in to the chimney and the exhaust gases rise up the annular space between the chimney walls and the metal vent liner.  The heat created by the water heater may not be enough to heat up this huge area.  The water heater vent needs to connect to the metal liner.



An obstructed vent. This one is a curveball that most home inspectors won't be able to diagnose.  While replacing a water heater once, I found a dead bird sitting on top of the draft hood.  No wonder why the water heater was backdrafting.

If you have a water heater that backdrafts, have it professionally repaired.  Your home inspector may be able to give you several potential reasons for the water heater backdrafting, but an obstructed vent is always a possibility, and without taking stuff apart, there's no way to know for sure.


Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspections



    

Don't Get Locked Out Of Your Garage

Check out the photo below.  Can you guess what's missing?  Here's a hint: this garage doesn't have a service door, but it does have a automatic garage door opener installed.



If you said "pizazz" you would be correct, and you might also make a good home stager, but that's not what I'm talking about today.  This door is missing an emergency release.

If the power went out, the GFCI outlet inside the garage tripped, or the garage door opener failed, the owner would be locked out of this garage.  The fix for this is quite simple - install an emergency release kit.



These kits cost about $15, and they take about ten minutes to install, if you really take your sweet time.  This is a very DIY project.  The only tools you'll need are a drill, drill bits, and a wrench.

These emergency release kits are very simple devices - they connect to the pull-cord on the garage door opener, allowing you to disconnect your overhead door from the opener, as shown in the photos below.

 

When I inspect old houses in Minneapolis and Saint Paul and I find garages without a service door, I always tell my clients to install an emergency release kit.  It could save a lot of hassle in the future.




Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspector

    

Top Ten Minnesota Home Inspection Defects For Old Houses

Top Ten Minnesota Home Inspection Defects

10.  Tree Branches Rubbing On The Roof Tree branches do a lot of damage to roofs.  Just think about branches rubbing on the roof all day long while the wind is blowing.  This adds up to a lot of damage.  Tree branches too close to the roof will also give squirrels, raccoons, and other pests very easy access to the roof.


9.  Double-Tapped Circuit Breakers Every circuit breaker in the main panelboard should have only one wire connected to it, unless the circuit breaker is designed for more than one wire.  Most aren't.  When two wires are connected to one breaker, this is referred to as a double-tapped circuit breaker.  Sometimes the fix for this defect is very quick and easy, sometimes it's a major project.


8.  Bath Fans That Don't Exhaust Properly I start my home inspections by turning on every fan in the house, and I make sure that air gets exhausted to the exterior.  I find a ridiculous amount of fans that make plenty of noise, but don't move any air.  The problems can be caused by disconnected ducts, ducts that aren't continuous to the exterior, blocked internal dampers, stuck external dampers, or kinked ducts.  A bath fan exhausting in to the attic is always the worst.  Every bathroom should have an exhaust fan.


7.  Missing / Improperly Located Smoke Detectors Smoke detectors should be present in a common area on every level and in every bedroom, and the installation instructions need to be followed.  I can't tell you how many smoke detectors I see tucked away in to corners - this is never an acceptable installation, because smoke won't get there fast enough.


6.  Missing Cover Plates Missing or broken cover plates at outlets and switches are shock hazards, period.  Common problem, easy fix.


5.  Improperly Wired Outlets Ungrounded three-prong outlets and outlets with reversed polarityare very common defects.  These are shock hazards.  You can check the outlets in your own home with an outlet tester that costs about five dollars.


4.  Missing Carbon Monoxide Alarms. Minnesota requires carbon monoxide alarms within ten feet of every sleeping room.  Lots of people put them in the same room as the heating plant; that's fine, but it's not required.


3.  Poor Water Management This consists of the same thing every time - negative grading and improper downspout extensions.  This is almost always the cause of wet basement and foundation problems.  The grading around the house needs to slope away, and downspout extensions should take water well away from the house.  Improper downspout extensions are worse for the foundation than no gutters at all.


2.  Missing Anti-Tip Devices At Ranges Ranges have been sold with anti-tip brackets since 1991, but it's pretty rare for me to find the brackets installed.  These are required to prevent ranges from tipping over, which could cause serious injury or death to a child.


1.  Attic Bypasses I find these all over the attic on almost every old house I inspect.  Attic bypasses allow conditioned household air to leak in to the attic space, and they can reduce the effectiveness of insulation by as much as 70%.


Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspections

New Construction Inspections

One of the most common myths related to new home construction is that new homes don’t need to be inspected.  I personally know several people that have purchased new homes and didn’t have them inspected because they were ‘new’.   I’ve seen far too many problems on new construction homes to think that they’re not worth first inspecting, regardless of the builder.

One common myth that builders will sometimes tell buyers is that the home has already been inspected many times by the city as part of the permit process, so the buyer is wasting their money hiring a private inspector.  While there may have been many brief inspections performed by the city along the way, things still get missed every day.  Did you know that unless a ladder is provided at the site for the city inspector, they won’t even get up on the roof to inspect it?  It’s actually common practice for roofers to leave a few photos for the building inspector to look at to sign off on the roof.  The photos below show a hole in the roof of a new construction townhouse that I recently evaluated, and the builder was a reputable, well known builder that you’ve definitely heard of.  The builder had actually tried to talk the client out of getting a home inspection.

Another myth is that because a home is new, there won’t be problems.  While new homes don’t have the same types of problems as old homes (such as components reaching the end of their life expectancy), they can still have serious issues, typically related to improper building and installation methods.  These are the types of issues that an average homeowner will know much less about; it’s easy to look at cracks in a foundation or rust in a furnace and know there’s an issue, but it’s impossible to identify installation defects without knowledge of building, mechanical, plumbing, and electrical codes.  While a private inspection is certainly not a code compliance inspection, an excellent home inspector will be aware of code requirements , and will be looking for any problems.

Below are a few photos of problems I’ve found at new construction homes, or homes that were relatively new.  Remember, these were built by big, reputable builders.

This window was on a second story, and I suspect it had been dropped before being installed.

The two photos below show a whole house fan that was supposed to be exhausting to the exterior; the bottom photo shows the wall that the fan should be exhausting to.  Obviously, the person installing the siding went a little too fast.

 

These photos show where a roofer was going too fast - they forgot to install the damper for the bath fan exhaust, so there was just a hole in the roof.

 

This photo shows the heat duct and the exhaust opening for the HRV, located right next to each other in a basement bathroom (one supplies air, one sucks air out).

I can't tell you how many plumbing vents I've seen with knockout plugs still in place. These are supposed to be removed after the final plumbing inspection, but it's commonly forgotten about.  This means that the plumbing fixtures are not vented.

Many, many, many air conditioners get installed with the wrong size circuit breakers.  Note the text on the label for the AC that reads in all caps "MAX FUSE OR MAX CKT. BKR. - 20"  The 30 amp breaker is what fed the AC unit.

I could go on and on with these photos, but hopefully I've made my point; new homes need home inspections too!

Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspections