Heating system

Make-up Air

Make-up air:  The volume of air that is required to replace exhausted air from a given space.

If you have gas appliances,  a well weatherized and insulated home, and exhaust fans check out the following video for a serious consideration….


Please read when installing

Funny thing about labels, they can tell you some useful things but there is a trick…..you need to actually read them.

There are labels for almost anything, to tell you when you should purchase something, or throw it away or even how it should be installed…..

I was in a Salem, Oregon attic the other day and I noticed some labels.  These labels were on building components and the labels had instructions or indications for how the product should be installed.  The first label I noticed was on the fiberglass batt insulation:

Clearly, right on the surface of the paper face were some instructions, “Apply this side toward living space.”   I was in the attic space and it was definitely not set up for “living.”  The reason for this label has to do with the movement of moisture vapor as it leaves the living space and enters an unheated space.  With the vapor barrier/paper face installed improperly, water vapor that is traveling up through the ceiling and through the insulation hits the big temperature difference at the paper face and condenses into liquid.  Here the liquid water is trapped and will cause bad things to happen to the home (mold, rot, deterioration, ect).  When the paper face is installed properly the vapor will not hit the dew point till it is past the vapor barrier/paper face and if the vapor condenses into liquid in the fiberglass batting, it can breath and escape and most importantly, is not trapped!

A few feet away I saw another label.  The manufactures for the gas flue for the water heater wanted to help the installers and make sure to remind them of proper installation:

Looks like this was another instance of lack of proper literacy.   The purpose for the 1″ gap requirement is fire safety.  The type B vent is designed to stay cooler than a straight walled pipe however it does heat up.  Over the years the combustible materials that are too close to the pipe will heat up over and over again.  Each time this heating occurs there are slight changes in the molecular structure and the material’s flash point, temperature that it catches fire, drops.  Eventually this may become a fire hazard.

Labels are important.  Read, read, read and if you don’t know why you should do something, call someone, like a wonderful home inspector, who does!

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Not everyone knows about the Old Cadet fire hazards that lurk in Salem Homes.

A few years ago a little company was producing a neat little electric wall heater that was easily installed, relatively inexpensive and allowed wonderful zonal heating (read-“energy efficient”)!

Things were wonderful for sometime but like most things there were a few issues with the first models. The little electric heaters were made by the Cadet corporation and after the release to the general public it was discovered that if housekeeping was not top notch these little heaters had the tendency to overheat (read-“catch on fire” and there could be “flames, sparks or molten particles spewing through the front grill cover of the heaters into the living areas”)!

The problem arose at the heat exchanging point. This is the point in every heating device where the heat that is produced in the heating device is transfered or “exchanged” to the medium that will carry heat to the home. The little wall heaters used fans to transfer heat directly to the home’s air through convection.Heat transfer of convection to describe problems with cadet heaters

The more surface area that the heating device can have exposed to the house air the better the transfer of heat. The more volume of air flows through the device the better transfer as well. There is a point between these two conditions where a balance between the two is chosen.

The little wall heaters that were brand new, met both of those expectations very well. Lots of heating elements (red hot wires) exposed to the air and the little fans did a very functional job of moving a large volume of air over the heated electric coils.

To prevent the red hot wires from getting dirty, which would insulate the heater elements from the air, hampering the exchange of heat, a small screen was placed in front of the fan. The little screen did a good job of keeping the elements clean, too good of a job.

The screens, especially in dusty areas or homes with pets became plugged very quickly. Even with the label on the side stating, “clean the heater fins every month,” these screens and heaters got neglected.Recalled cadet wall heater showing the vulnerability to over heating and fire in during a Salem Home Inspection

Although the heaters had wonderfully clean elements, the flow of air had been destroyed by the plugged screens. The thermostats didn’t know about the restriction of air and kept asking for heat. The elements got hotter and hotter as very little house air was able to flow over the elements to absorb the heat. This occurred over and over until the unit or the wall or both caught fire.

This is not new information as the CPSC noted the recall in Jan 1999. However, I still see the dangerous units in homes that I inspect around the Salem area.

The moral of this tale is; while we are in our friends, family and neighbor’s homes this holiday season we should keep our eyes open for these dangerous units. We should mention the recall to our hosts if we notice the electric wall heaters.

The way to determine if the units are dangerous is the model number.  You should look for: models FWFXLXTKZAZRARKRLXRXRW and ZC

The model number should be on the inside of the unit and behind the front panel.  At the risk of being like me, “that annoying home inspector guy,” you should try to locate the serial number without removing the panel.  I have learned that it is rude to take out a screw driver and start removing panels during a dinner party!  Also there is that little thing of high voltage live wires behind the panel…..

At the very least, you have a conversation starter for those awkward moments during the parties……..Where to find the cadet wall heater model number for the recall verification on a Salem Oregon home inspection

What your Furnace shouldn’t look like!!

Home inspections are good for getting a basic look at all of the major systems and components of a home.  This means that the nature of an inspection is general.
One of the general tests that good home inspectors do is to fire up the furnace.  Before I was an inspector I thought, “Why should I pay for someone to turn on my furnace?  I can turn on a furnace and tell if it works!”  This is a fact, however, there are things that a good inspector will look for when the furnace fires up that I would not have known to look for before I was an inspector.
One of the main things that good home inspectors look at while the gas furnace fires up is the flames.
  • Proper operation of the furnace will have the flames turn on with a steady blue.
  • Once the heat exchanger is heated sufficiently the main fan (that will blow heat through the home) turns on
  • The flames should remain steady and blue with little to no change in shape and color when the main fan turns on
This video was taken on a recent Salem, Oregon home inspection that shows what a flame SHOULD NOT look like when the main fan initiates:
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Jim Allhiser President/Inspector
503.508.4321         jallhiser@perfectioninspectioninc.com

“No Surprises!”

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Mark Gagle’s take on Salem, Oregon Heating and Air Conditioning

Mark Gagle, owner of a local Salem, Oregon heating/air and plumbing company; Gagle’s, answered some questions I had on AC.  Specifically I asked about size of the outside unit in relation to the sqft of the home and fenestration (windows and general heat loss) and one-story compared to two-story homes:

“If it is a newer home the windows, doors, insulation and direction facing are
not as critical on homes built from the mid 90’s to date. Anything prior to around
1994, the homes were not as well insulated and the windows and doors are more
of a factor. The most important factors for A.C. are the size of the return air coming back to the furnace/air handler and the location of the supply
registers for the second story of a home
If you have a single story home;
650ft. per ton is great. If you have a two story, main floor and upstairs, go
down to 550 to 600 ft. per ton.

What I’m finding out there is a lot of homes
were designed for heating only
, and not for adding A.C. The supply registers for
the upstairs need to be in the ceiling, not the floor! Warm air rises, but cold
air drops. In heating mode, the upstairs works fine because the main floor is
helping to heat the upstairs. But in cooling, unless the registers are in the
ceiling, you won’t cool the upstairs!  On most two story homes, the bedrooms are
all upstairs, and that is were you want cooling.

Another factor is the
thermostat location. It is usually located in a hallway, under or near a return
air grill. That is perfect for a single story home. By drawing air across the
stat going into the R/A [return air] grill you are always getting a accurate reading of the
indoor air temp. But the stat is also the systems sensor, and that is why the
upstairs is always warmer with a two story home. Once again warm air rises, so
all the heat from the main floor ends up upstairs! The same principal is true
for a main floor/basement home. Most two story homes have a 5 to 10 degree
temp. difference between floors.

As for return air duct sizing back to the furnace
for adding A.C.: a 14″ round duct is good for a 2 ton system. A 16″
round is good for a 2 1/2 to 3 ton system. A 18″ round is good for a 3 1/2
to 4 ton system. A 20″ round is good for a 5 ton system. These numbers are
for the max. size for adding A.C. If you don’t move enough air across a A.C.
I.D. coil you will turn it into a block of ice, and have to put the system into
heating to defrost the coil! The round sizes can be converted into rectangular
by multiplying by 3.14 (Pie) That will give you the sq. inches needed for
rectangular ducting.”

Of course this information is above and beyond what a home inspection is about (general visual inspection of systems) but it is still a good thing to know about as it may help me educate my clients more thoroughly.

If you have specific questions about duct sizing and AC/Heating system function refer to a Salem, Oregon Heating and Air contractor, but for questions about general systems, including structure, plumbing, electrical, kitchen appliances, etc….ask me, your Salem Oregon Home Inspector.

Jim Allhiser President/Inspector
503.508.4321         jallhiser@perfectioninspectioninc.com

“Always on the cutting edge”

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Heating Oil Tank Program in Oregon

Oil tanks were very common between the 1920s and 1960s to store the relatively cheap heating oil for the oil furnace. If the home has exchanged hands a few times a hidden underground tank may not be known about. The presence of hidden underground oil tanks is an issue that can rear its ugly head on a home inspection every now and then. Thankfully the Oregon DEQ is doing something to help.

The Department of Environmental Quality (DEQ) here in Oregon, has a program to help keep track of those oil tanks that may have been forgotten.

The site is:http://www.deq.state.or.us/lq/tanks/lust/LustPublicLookup.asp

There is a trick to using the search engine however: You must just enter the address number only!!

If you enter the street name it will not work.

If excavation or redevelopment is planned you can find information on known and suspected Heating Oil Tanks (HOT). Information on: if the site has received a closure letter for the decommissioning, assessment and certification of a HOT is available.

If a HOT is present there may be contamination of the surrounding area and a cleanup may be required. Decommissioning, assessment, and cleanup must be performed by a DEQ licensed HOT Service Provider.

For you agents out there check out this publication: What agents should know about underground oil tanks.   http://www.deq.state.or.us/lq/pubs/factsheets/tanks/hot/BuyingSellingHomeHOT.pdf

I posted this information a few months back and the links were not functional (my own mistake for not checking for myself). But last week I actually found two little copper line in the crawlspace on a home in Silverton. These lines are a great indicator of underground storage tanks so I raised a bright orange flag and alerted my client. The home had been owned by 4 different people in the last 20 years and the current owner had the home for the last 6 months. There was very little chance the current owner had a clue about oil tanks and whether proper decommissioning had occurred.

So I tried the search myself and by entering the address numbers but not the street name found documentation that the tank had leaked and had been removed and cleaned up in 2003! That is info that can now be linked to the home no matter who owns it.

Kill your heating system one month at a time

How great it feels to take a deep breath. To feel the stretch of the lungs as they fill with air. It is refreshing and satisfying.


A little dramatic, I admit but it is very similar to how your furnace feels. Most forced air systems use a big fan to suck air in and push that air over a heat exchanging device and then blow that newly conditioned air throughout the home. The thermostat, usually located centrally in the home, calls for heat the furnace starts heating up. When the brains of the furnace decide the heat exchanging area has heated up enough the fan turns on. It is now the fan’s job to pass air over the heated area and blow that heated air throughout the home.

It is my job to look at furnaces and filters every day and as a general rule: people change their furnace filter when they move in and when they move out. When the filter is dirty the fan is forced to work much harder. Less air is moving over the heat exchanger so more energy is used. This also shortens the life of the entire unit.

Change your filters at least every 30 days in the cooling cycle and 60 days in the heating cycle at least. It will save you money on energy, extend the life of your system and give your poor furnace a welcome breath of fresh air.

Comfort level: Regular, Delicate Sheer, or Permanent Press?

Home owners can be very creative people. This is especially true of people from previous generations and people here in South Salem, Oregon.


If I had a nickel for every automotive part used in plumbing repairs that I have seen….I would have enough for a happy meal….maybe.


Recently while diligently checking a home’s heating system this dryer control knob was noted on a wall heater. I am not sure how hot ‘permanent press’ is or even ‘Delicate sheer’ but I am sure the knob fits tight and with a little training, might help dry the home’s air.



Air conditioning your Home when it’s cool outside (how to ruin your AC unit)


I came across an outdoor AC compressor the other day that was running at full speed. This was not immediately unusual, because it is August. Then I realized that at this early hour of the morning the outdoor temperature was only 50 degrees Fahrenheit! Upon closer inspection I noticed one whole side of the compressor was covered with about a 2 inch layer of ice!!

After I ran into the home and quickly turned the air conditioning off, I took a side bar with my clients and explained how an Air conditioner works: Through the powerful processes of evaporation and condensation the AC unit is able to absorb heat from the inside air and exhaust it outside. Right before the coolant enters the home it has been cooled and evaporated so it is a low pressure gas. After the warm house air is passed over the cool coil the coolant that has absorbed that heat travels outside is compressed and is a high pressure/high temperature liquid. Now the outdoor air which is cool compared to the compressed high temp liquid (100 degrees F is much cooler than 180 degrees F) is passed over the coils and heat is exchanged. Then the liquid is evaporated and it is cool again and cycled back in to the home.

The fatal flaw that can be noted on a cool day, is the inside air is not warm enough to absorb an adequate amount of heat from the gas. This causes ice to form. The ice covers the small metal fins that the air is blown through to exchange heat. If the heat cannot be exchanged the low pressure/low temperature gas cannot continue to drop in temp. Eventually the compressor, which should only compress gas, will try to compress liquid. When the unit tries to compress liquid the AC unit is toast.

The outside temperature being above 65 F is critical to testing AC units. For around 6 months of the year home inspectors in Salem, Oregon cannot test the AC system because the outdoor temperatures are too low. On most units there will be a fuse or switch near the outdoor unit. After September it may be a good idea to turn the unit off to prevent accidental cycles.