Troubled Houses - The Home Owner's Resourcesm - Heat & AC
We see many interesting adverse conditions during our inspections, partly because of the unlimited number of ways people can mess up a house, but also because we do a thorough inspection to reveal these adverse conditions. We hope these stories and illustrations help home owners avoid these costly conditions by learning about causes, preventions, and remedies. A home purchase can create opportunities for the new owner to improve the home, possibly increasing its value, durability, and usefulness.
NOTICE TO BUYERS & SELLERS: This site does NOT encourage or discourage the purchase of any individual house, or style, age, location, or condition of house. Conditions shown and/or described in the following articles may have been remedied at the house where these conditions were found. These conditions typically can be remedied by qualified contractors. The presence of these conditions in any house is comparable to any other real estate consideration such as price, size, or location. Consult a qualified home inspector before purchasing any house, and consult a qualified real estate agent for more information on how to handle a real estate transaction where adverse conditions are reported in a home inspection. This site does not describe any house by address or knowingly show a readily identifiable exterior image. Further, no home actively listed for sale on the Twin Cities MLS will be described on these pages at the time the article is posted.
Copyright 2014 HankeyandBrown.com. All rights reserved. "Troubled Houses - The Home Owner's Resource" is a SERVICE MARK of Hankey & Brown Inspection Service Inc. List of topics and all articles in this resource. (Also includes Photos of the Month.)
Heating, Ventilation, and Air Conditioning (HVAC) story list
Improper air ducts reduce comfort
Why we open the attic hatch. (Broken vent)
Attic inspections are necessary
Chimney Cap Comparison
Furnace inspections are critical (damaged heat exchanger)
Frosted (deteriorated) siding (reversed vent terminal)
Warm but with the potential to poison (boiler leaking fumes)
Permitted, installed, but NOT inspected (poor workmanship)
The Unintended Humidifier (Condensate leaks)
Undisclosed Buried Oil Tank
Gas fired equipment should not make soot! (Gas fireplace)
Drywall dust hurts heating and cooling equipment!
Use the recommended furnace filter!
Clean the air intake on your heat recovery ventilator
Don't rely on inspections done for others!Also see our Carbon Monoxide Tests page
A rare, but potentially serious furnace maintenance issue (reversed cover panels)
Permitted, Installed, but NOT inspected! Incomplete and incorrect workmanship
Early in 2014 we inspected the furnace shown
Four adverse conditions in the HVAC system are shown in the photo at right:
1. The filter opening at the bottom right side of the furnace is uncovered.
The uncovered filter slot further reduces the return air flow at upper floors and permits unfiltered air to reach the coils of the furnace and air conditioner.
A check of the city records for this property found that a permit was issued for intallation of this furnace in November of 2009, but that three attempts to inspect the furnace in 2011 failed and it was not listed as approved. This could explain why we found these conditions in early 2014. We recommended these conditions be corrected by a qualified HVAC firm and that a final inspection by the city confirm a proper installation.
Improper air ducts reduce comfort in a heating-cooling system
A forced air heating & cooling systems include both supply and return air ducts. A large blower in the furnace moves air into the furnace via "return" ducts which have negative air pressure (suction) and out of the furnace via "supply" ducts. The return air ducts must be tight to establish good suction at the return air grills in the various rooms. The photos above show two of several problems with the return air system on this 1992 built home. The left photo is of a return air duct in the unfinished area near the furnace. The part of the return air duct was created by installing a sheet metal "pan" on the bottom of the floor joists. Unfortunately the installer forgot to install an end cap in this return, so this return is not conveying suction (negative or return air flow) to the return grill on the room above.
The right photo shows that the combustion air duct (black tube) is directly connected to the furnace blower cabinet. Each time the furnace blower runs, air is drawn in directly from outdoors, whether the house needs extra air or not. Installations similar to this (combustion air direct connected to the return air duct, not the blower cabinet) were commonly used in the 1970's and 80's. Good practice today is to simply bring the combustion air duct to the furnace room as a passive air supply (shown below). This prevents the blower from pulling unconditioned air (hot, cold, damp or dry) directly into the furnace by this air duct, whether the house needs extra air or not. The passive duct allows air to enter when the air pressure in the house is lower than air pressure outdoors. This can occur when exhaust fans, dryers, or the furnace or water heater are in use.
In this case, we recommended both the return ducts and outside air supply be corrected by a qualified heating contractor to improve air circulation in the house and improve the efficiency of the system. We also suggested replacement of the 17 year old furnace with a sealed combustion direct vent furnace to take advantage of the 30% Federal tax credit for energy efficiency improvements done by the end of 2010. Return to story list.
Furnace inspections are critical (damaged heat exchanger)
A careful furnace inspection is necessary to identify potentially dangerous conditions. This 53 year old furnace had a cracked vent connection on its heat exchanger. (between A & B in the photo) Replacement was recommended since this crack was on the suction side of the blower (see inset image) which could pull combustion fumes into the circulating air. (This furnace design was abandoned by manufacturer's more than 42 years ago.) The furnace had been "certified" by a reputable heating company only 5 days prior to our inspection. The company rechecked the furnace and agreed with our findings. Our customer obtained a $3,500 price reduction from the seller to help cover the cost of a new furnace.
This one year old house has cement fiber siding and a gas fired high efficiency furnace with a sidewall vent. The vent pipe and air intake pipe are reversed in the terminal directing moisture onto the wall and causing siding deterioration. The terminal needs to be turned 180 degrees to direct the vent out the front opening instead of onto the siding.
Warm but with the potential to poison
This 80 year old boiler was designed to burn coal, then converted with a gas burner over 42 years ago. Of course it is very inefficient, but worse yet it has not had regular maintenance and has many unsealed gaps and joints (one shown below) that leak combustion fumes into the building.
We recommended boiler replacement for efficiency, reliability, and to reduce the potential for carbon monoxide leakage. If the boilers are to remain in use, we recommend having a qualified technician seal all the holes, gaps, joints, etc. Click here to learn more about our services. Return to story list.
This modern high efficiency furnace is classed Category IV (condensing type) which means its vent temperatures are so cool (about 200ºF) that considerable amounts of water must be drained from the secondary heat exchanger and vent. Unfortunately this furnace has one or more condensate leaks in the hoses and fittings which are intended to convey the liquid condensate (slightly acidic water) to the nearby floor drain.
This kinked hose is one of at least two places where the condensate is leaking out of the furnace and into the blower cabinet. Note the extensive corrosion due to the acidic condensate spill. This is a common problem with this type of furnace. Annual service is recommended to catch these conditions before the furnace is damaged.
The furnace blower cabinet and its insulation are wet. The metal is rusty and the insulation has a high potential for mold growth. Another common adverse condition is the installer's failure to secure and seal the bottom panel of the furnace blower cabinet. Presently the furnace draws some air through this loose panel whenever the blower runs, reducing the effectiveness of both heating and cooling. Our inspection report identified these conditions and recommended correction by a qualified heating technician.
The seller of this "Prairie School" architect designed home near a city lake was unaware they had an abandoned buried oil tank. Our inspection saved the buyer the $3500 tank sealing costs. Click here to see what our customers say about our service.
The chimney on the left has had its cap replaced with a concrete cap which sheds water. The chimney on the right has its original mortar cap (a typical mortar crown) which lets water run down the side of the chimney. This has lead to freeze - thaw damage to at least six bricks on the visible side of the chimney. This chimney would benefit from brick repair AND a new cap to prevent further freeze thaw damage. Our inspections include roof & chimney when readily accessible. Click here for more information.
We occasionally get some resistance from real estate agents and home owners about opening an attic hatch that has its original spray texture or drywall joint cement coating. These hatches are installed to permit the attic to be insulated and for service work such as cable installations, etc., as well as inspections. These hatches are not "sealed" and typically can be opened with simple upward hand pressure. When carefully opened and reclosed, there is almost no sign that the hatch was even disturbed.
If the ceiling finish on the hatch is completely intact, it is unlikely anyone has viewed the attic since the house was built. There are a wide variety of adverse conditions that might be present in the attic, and can ONLY be discovered by an attic inspection.
This six year old townhouse has a metal vent for the furnace and water heater which extends about 3 feet above the roof. When viewed from the exterior, the vent looks completely normal. The attic hatch had not been opened.
A view of the vent from the attic hatch shows the vent in the far corner of the attic, rising up and out near the top of the attic. There is a slight indication of an abnormality at the 45º elbow near the roof penetration. A closer look, obtained by crawling across the roof trusses and verified by inserting a folding rule into a gap in the vent, reveals the vent has separated at a joint in the elbow.
This broken elbow can permit the products of gas combustion, carbon dioxide and water vapor, to enter the attic. Left undiscovered, winter operation of the furnace vent would discharge a large amount of water vapor into the cold attic where it would condense on the roof sheathing. Conditions such as this have caused extensive water damage in other cases. A prompt repair of the broken vent elbow, by a qualified HVAC firm, was recommended. We contacted the management of the townhouse owners association and recommended attic inspections of other units in the townhouse complex. Potential causes for the break in the elbow are impact with the exterior portion of the vent due from activities such as reroofing, or use of the sheet metal angle brackets on the underside of the roof. These brackets may restrict the movement of the vent as it expands and contracts from heating and cooling, causing the vent to pull itself apart at the elbow joint.
Gas fired equipment should not make soot!
The metal box on the wall below this elevated porch is the vent terminal for a direct vent gas fireplace of a 1990 built home in Chanhassen, MN. Notice the blackened area on the box and darken siding above the vent terminal. This area is shown in detail below.
The black deposits on the vent terminal and siding are soot, a form of carbon that is a classic sign of poor combustion. (Often due to insufficient combustion air). This is true of ALL gas fired equipment from a kitchen stove to a furnace. Soot should not be present in the combustion chamber or on the vent. The equipment should also NOT be making any odor (although a gas furnace or gas fireplace may occasionally create a slight odor of toasted dust when operated after a long period of non-use. The carbon monoxide reading in the vent was over 41 0 ppm. (Under 100 ppm would be normal). The recommendation in this case was to have the fireplace serviced as soon as possible by a qualified gas fireplace technician and tested for carbon monoxide.
Attic inspections are necessary
A thorough home inspection involves examining ALL readily accessible areas of the house, AND mentally connecting the conditions found in one area with the condition of related components located elsewhere in the house. This is particularly true of a heating system which often has components such as a chimney that extend from the foundation to above the roof. Often, when conditions are found in multiple areas, the experienced inspector will relate these individual observations to the overall performance of the system. The chimney of this 99 year old St. Paul home is a good example.
The City of St. Paul Truth in Sale of Housing report indicated that the attic was all finished rooms with no attic access, but this was not the case. We found and opened a hatch to the attic above the 3rd fl. rooms and found two conditions not listed in the city report.
We recommend that home buyers do NOT rely solely on required municipal Truth in Sale and Time of Sale evaluation reports. These reports are NOT the same as an inspection done to the ASHI® Standard of Practice home inspection. Also see: Don't rely on inspections done for others.
DRYWALL DUST HURTS FURNACES AND COOLING COILS
Forced air heating systems are not intended to be used during construction. This is particularly true during the sanding of the gypsum wallboard joints. We have recently encountered several homes where this recommendation was not followed. We have seen this in both new homes, and older homes where an area was remodeled and where new rooms were added.
Gypsum wallboard dust is composed of very fine particles and this dust is almost pure white. It travels throughout the heating system and coats the blower, heat exchangers, cooling coils, ducts and continues to blow into the home whenever the blower operates.
The dust is much more than a cosmetic problem. First, drywall dust is a known health risk. There are occupational regulations on the control of drywall dust. Further, and more important to the home owner, manufacturers of furnaces, air handlers, and coiling coils know that the drywall dust can cause corrosion on metallic surfaces of the heating equipment, and a layer of dust reduces the efficiency of heat transfer on the heating and cooling components. Most manufacturers do NOT recommend use of the furnace as a construction heater, and when the furnace is used, the installation instructions carry very specific instructions on how the furnace is to be used, maintained, and cleaned prior to regular use of the equipment. Failure to follow the instructions can void the warranty.
Most reputable builders do not use the furnace during construction and best practice is to seal off any heat registers and grills during drywall sanding so that the dust does not contaminate the heating and cooling system.
<- One way to check for drywall dust is to open the filter cover and look into the return air duct.
Use the recommended furnace filter.
The image at right shows that whoever installed the blue and white filter did not read the CAUTION label or deliberately chose to ignore the message on the label. Worse yet, the 1" wide filter selected is a costly filter and if left in place more than a month has a high potential for causing over heating damage to the furnace. Four inch thick filters are recommended whenever the filter rack can accomodate that size filter. Four inch thick filters can last six months to a year and do an excellent job of filtering out fine particles from the air.
Clean the air intake on your heat recovery ventilator
Thousands of Minnesota homes built since 1985 have air to air heat exchangers, also known as heat recovery ventilators installed to improve indoor air quality. These devices drawn in fresh outdoor air while exhausting an equal volume of stale indoor air. The two air streams pass each other in a heat exchanger and the exhaust air gives up about two thirds of its heat to the incoming air. Hence, the name, heat recovery ventilator. See drawing below.
Unfortunately some of the maintenance tasks described in the drawing are overlooked or forgotten by a large majority of home owners. This is particularly true of the task of checking and cleaning the air intake. A typical air intake location is shown below.
A look into the hood reveals that the metal mesh over the intake is completely clogged with cottonwood tree fuzz and dust.
When operating without intake air, the device becomes an exhaust only fan. This can lead to numerous adverse consequences including elevated levels of moisture and radon, cold drafts, and higher heating costs. Cleaning the screen is easy with a car windshield snow brush. The key is to make a schedule to ensure that this screen is checked several times a year so that it can be kept clean.
Don’t rely on inspections done for OTHERS.
The information provided in disclosure documents or inspections done for OTHERS can be incomplete, incorrect, false, or not intended to meet the needs of home buyers. We recommend that home buyers obtain inspections done to meet their needs by vendors that respond directly to them.
Editor's Note: This article was submitted to US Inspect, City of Minnetonka Inspections Dept., the heating contractor, and our customer, for comments prior to posting. This article incorporates comments received from the heating contractor and the city inspections dept.
Inspection reports done for purposes other than pre-purchase often include statements that home buyers should not rely those reports. For example, the Worldwide Employee Relocation Council (ERC) Property Assessment has headlines and text which state:
This document is a Property Assessment. It is not a buyer's home inspection.
This document should not be used in place of nor be mistaken for a general home inspection or specialty type inspection performed by a licensed or trades professional (e.g., professional home inspector, engineer, pest control operator, electrician, plumber, roofer or HVAC specialist, pool/spa specialist, etc.).
This Property Assessment was prepared exclusively and for the sole use of the Client identified below (the "Client") under an established business-to-business relationship for the specific purposes of assisting with the relocation of an employee. It is not intended for use, nor is it to be relied upon, by any party other than the Client, including, but not limited to, buyers, sellers, lenders, real estate brokers/agents, and/or appraisers.
The Client may be required to provide this Property Assessment to other parties in order to comply with disclosure obligations under applicable federal, state and/or local law(s); however, no disclosure of this Property Assessment to other parties, including prospective buyers, shall be deemed to create or give rise to a duty of care or performance on the part of the Property Assessment Provider identified below or the Client toward such OTHER (emphasis added) parties.
Accordingly, no party OTHER THAN THE CLIENT (emphasis added) may rely upon or be influenced by this Property Assessment when considering the property. The Property Assessment Provider prepared this Property Assessment in accordance with Client directives and based it on findings gathered at the property address identified below AND OTHER (emphasis added) property information sources. END OF QUOTE.
We recommend you obtain a copy of reports such as the ERC or other inspections and provide them to the inspector YOU hire. The inspector will benefit from some of the basic information provided in the report and will be able to cross check the inspection findings.
We recently encountered an ERC report, done in September 2014, by US Inspect, a nationwide vendor of relocation inspections.
Our customer had forwarded us the ERC report which we reviewed prior to our inspection. Starting on line 1 of the first section, the report was incomplete (no status rating for walkways). The attic section had 3 unrated line items. There were 2 unrated basement items. The electrical section had no rating on the smoke detector line. The heating section had 4 unmarked line items: thermostat, humidifier, draft control, and pressure relief valve. Further, the furnace was listed as approximately 5 years old, when a check of the online city permit records showed the furnace was installed in April 2013.
We participated in the design of the ERC form, over 20 years ago, and know that every item is to be marked, since one of the ratings is “not present”. ERC reports also include a set of photographs. Our review of the photos led us to believe that there might be unreported concerns in the attic. Given the many unrated items and the unreported possible concerns in the attic photos, the customer hired us to do an inspection of most of the systems in the house.
Our inspection revealed one main area of concern:
- the furnace vent was connected to a masonry chimney without a metal liner as required by the furnace manufacturer
The furnace situation illustrates why home buyers should not rely on city permit inspections or heating contractors. We found the installer’s test tag proving the date of installation. (4-26-2013). Also present was the furnace installation manual for this Goodman GMH 80 furnace which stated that if a masonry chimney is used as a vent, the chimney must have a metal liner. No metal liner was present.
Online city permit records show the permit was issued April 30, 2013, for a furnace & AC. The city final inspection was on 5/17/2013, and approved by inspector Todd T.
The furnace is an 80% AFUE induced draft model. (Fan-assisted category 1)
An article entitled “Venting Gas Appliances” by Bob Dwyer & Mark Gronley in the Feb. 2003 Journal of Light Construction, outlines the reasons why the furnace needs to be vented into a metal liner.
“Fan-assisted Category I furnaces use an inducer fan to overcome air resistance in the combustion chamber but do not pressurize the vent system. No dilution air is introduced, so the exhaust is damp and condenses readily.”
A few basic do’s and don’ts will take you a long way toward getting good results:
• Never use unlined chimneys. Avoid masonry chimneys even with tile liners.
Reline chimneys with listed liners or B vent.
Chimneys are especially vulnerable: Acidic condensate eats through tile flue liners and destroys brick masonry.” END OF QUOTE.
Our inspection report had a photo of the interior of the chimney showing the lack of a metal liner, a correct listing of the age of the furnace, a statement indicating the installation was not in conformance with the furnace manufacturer’s requirements and increases the potential for moisture damage to the chimney. We recommended the installation of a liner or furnace replacement with a high efficiency sealed combustion model that does not use the chimney. While not in our report, the cost estimate for the replacement furnace would be about $3,000. Also see Attic Inspections are necessary.
The City of Minnetonka response is: “We are very proud of the quality and consistency of the inspections conducted by our city inspectors at both homes and businesses in Minnetonka,” said Bob Manor, city of Minnetonka building official. “However, we are providing an inspection at a certain point in time, often when work has already been completed. In this case, we missed a manufacturers requirement we should have caught. Once it was brought to our attention, we offered to re-inspect the work, but the property owner didn’t take us up on that offer.”
“Our city inspectors are highly trained professionals who have caught many more potentially dangerous or hazardous conditions than they have missed, so I continue to believe in the value of our inspections to protecting the health and safety of our residents,” Manor finished. End of Minnetonka response.
We found several less costly concerns including:
Displaced and compressed attic insulation (visible in ERC photos)
Uncapped openings in the front cover of the electric service panel
Exposed wiring on the rear patio for a former hot tub (visible in ERC photos)
Sump pump discharge was within 2 ft of the house foundation
Water intrusion questions raised in the ERC report were found to be a prior slow leak at the main water valve.
We also found that the ERC report included a completely false and distracting comment about the lack of a fireplace damper clamp for a “gas fireplace log”. No gas fireplace log was present, and NO evidence was found that there had EVER been a gas line installed to ANY of the fireplaces in the home.
Our customer was very pleased he chose to have an inspection done on his behalf, since the final resolution of this matter was that the heating contractor replaced the furnace with a direct vent sealed combustion furnace that did not rely on the chimney for venting.
A rare, but potentially serious furnace maintenance error
The result of the misplaced covers was an extremely dirty system since the blower cabinet was pulling in unfiltered air. Our report recommended the system be cleaned and corrected by a qualified HVAC firm. We further stated that the furnace was at the end of its normal service life.Nine days later, I found another Carrier 58WAV furnace, 21 years old, with the same reversed covers situation. In this case, the furnace was clean enough to operate briefly. However, a carbon monoxide test in the vent produced results consistent with a heat exchanger defect. (CO levels rising after the blower came on.)
This furnace is VERY similar to its down-flow twin, model 58ZAV. The image shown at right compares both models. Notice the similar size, shape, and cover designs.
These images suggest that Carrier found it cost effective to make the covers fit either furnace. There is no marking on either cover to inform the owner or occupant of the proper cover locations. Both covers will fit in either location and when installed, both will depress the blower safety switch. This model furnace was also offered in the Bryant label and other brands built by Carrier.
Persons unfamiliar with furnaces or who have only seen down-flow furnaces may not realize the proper cover position on up-flow furnaces, and vice versa. While it is easy to correct reversed covers, the consequences of reversed covers include poor air circulation particularly in cooling mode, improper combustion due to insufficient air in the burner compartment, and if the covers have been reversed for an extended time, inefficient heat transfer due to dust coating all the surfaces of the heat exchanger and cooling coil. Additionally, if an atmospherically vented water heater is alongside the furnace, the unrestricted airflow into the blower has the potential to downdraft the water heater.
While researching this story, I was able to find only one other inspector’s website with an image or discussion of reversed furnace covers. His example was a Trane furnace.
HOME INSPECTORS: When encountering any of these very popular furnace models, it is recommended you explain the proper cover location to the customer and mark the proper locations on the covers, in addition to recommend cleaning and any other necessary corrections by a qualified heating & cooling contractor.Return to story list.
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