Ignition / Operation & Chimney Venting Recommendations For High Efficient Heating Appliances

 

Ignition / Operation & Chimney Venting Recommendations

For High Efficient Heating Appliances

Most of the heating appliances we inspect are higher efficiency. Yes there are some dinosaurs out there, but most have been updated. The efficiency of some units are over 90%. I want to go over the sequence of operation and important recommendations a home inspector should be looking for when inspecting higher efficiency chimney vented appliances. We will define “high” efficiency heating units as whole house furnaces / boilers that have an induced fan. You can see past newsletters discussing direct vent units. First the sequence of operation:

1 – Thermostat calls for heat

2 – Combustion air pressure switch proves induced blower operation. Pressure switches are factory set and require no adjustment

3 - After a 15 second pre-purge, the hot surface igniter or electronic ignition energizes

4 – Within 20 seconds, the gas valve solenoid opens

5 – The gas should be ignited within approximately 4 seconds

6 - Flame sensor proves the flame and the combustion process continues uninterrupted

7 – If a flame is not detected after the first ignition trial, the ignition sequence will repeat 3-4 more times before locking out the gas valve.

8 – If the unit does not respond, it will automatically repeat the entire heating sequence. Some units will have to be manually reset

9 – Depending on the unit, a reset button can be depressed or the thermostat can be turned to “off”, then back to “heat”

 Many times we see these units go through the starting sequence a couple of times before they activate. I would make a note on my report that “The heating unit did respond to the thermostat, however it cycled twice before properly activating.” It would be a good idea to advise your client to have it evaluated by a heating contractor.

 Many high efficient units are not vented properly. Sometimes there seems to be some confusion related to this. Often times we see a new high efficient unit installed in place of an older low efficiency unit. What about the flue pipe lengths? What about lining the chimney? What about the size of vent pipes? How many other appliances can be connected with a high efficiency unit?  Here is what a home inspector should be looking for:

 

·       Metal flue pipes should be secured to the furnace collar with 3 self drilling sheet metal screws or a mechanical fastener

·       The first metal vent connector should not have an elbow within 6 inches from the unit

·       The vent pipe should be properly supported without any dips / sags and shall slope a minimum of ¼” per foot

·       High efficiency (direct vent) appliances should never be vented into a masonry chimney without a liner

·       Many manufacturers recommend a masonry chimney that is tile lined must be lined with B1 vent or a listed insulated flexible metal vent (check with manufacturer recommendations)

·       An exterior tile lined chimney that is sealed and capped should be lined with a listed flexible metal vent

·       Insulation for the flexible pipe should be an encapsulated fiberglass sleeve recommended by the flexible vent pipe manufacturer

·       Do not insulate the space between the liner and the chimney wall with puffed mica or any other loose granular insulation

·       For multiple appliances venting into one chimney refer to the chart above

·       A type B1 vent liner shall terminate above the roof surface with a listed cap

·       A manual damper, barometric draft damper / regulator, or flue restrictor should not be installed between the unit and the chimney. (This may exclude oil fuel burning units – refer to the manufacture)

·        A flue pipe should never share a chimney with a solid fuel appliance or wood burning fireplace

·       When the flue pipe for a high efficiency appliance must be located or pass through a crawl space, attic, or other areas that may be cold, that portion of pipe shall be constructed of double wall type B vent material or material having equivalent insulation qualities

·       No portion of the venting system can extend into, or pass through any circulation air duct or plenum

·       The vent connector should not be sized more than 2 size diameters over the size of the draft hood outlet or flue collar outlet

·       The maximum length of a flue pipe for a high efficient chimney vented appliances:

      3” connector diameter = 4.5 feet

      4” connector diameter = 6 feet

      5” connector diameter = 7.5 feet

      6” connector diameter = 9 feet

      7” connector diameter = 10.5 feet

Inspecting Through The Wall Thimbles & Flue Pipes

 

Inspecting Through The Wall Thimbles & Flue Pipes

 

I think every home inspector has seen a flue pipe from a wood stove or a gas unit penetrating a wall or ceiling and think; “that does not look safe.” Whether it is the pipe itself or clearances, I have outlined some guidelines that may assist you in the field. Although there are many codes and accepted standards this is a good rule of thumb. Through the wall thimbles should be used for all applications unless not required by the manufacture. Horizontal runs of vent pipe must be supported to prevent any downward sagging. If the wall being penetrated is constructed of noncombustible material only, i.e. masonry block, brick, or concrete only, a hole with zero clearance to the vent pipe is permissible if allowed by the appliance manufacturer. See the graphic for through the wall thimble locations. The vent should not run downward. A downward slope can trap heat and become a possible fire hazard. Listed below are some recommended clearances by one manufacture:

 

• Clearance above the ground, veranda, porch, deck, or balcony is 12 inches minimum or over the snow line.
• Clearance to a window (operable or fixed closed) or door is 12 inches minimum.
• Vertical clearance to a ventilated soffit located above the termination cap (if soffit extends a horizontal distance of 2 feet out over the centerline of the termination) is 18 inches minimum.
• Clearance to an unventilated soffit is12 inches minimum.
• The flue should not be installed above a gas meter/ regulator assembly within 3 feet horizontally from the centerline of the regulator.
• Clearance to a service regulator vent outlet is 6 feet minimum.
• Clearance to non-mechanical air supply inlet to a building or the combustion air inlet to any other appliance is 12 inches minimum.
• Clearance to a mechanical air supply inlet is 6 feet minimum. 
• Clearance under a veranda, porch, deck or balcony: 12 inches minimum.

 

In addition to the recommended clearances a home inspector should be looking for the following conditions:

 

• Fire stops are required at each floor / ceiling level.
• Twist lock connections do not require screws are not required to secure the joint, but are acceptable provided they do not penetrate the inner wall of the vent pipe.
• Horizontal pipe sections should be supported at least every 4 feet.
• Most vents do not require sealant, unless specifically required by manufacturer.
• The horizontal run of venting must be level, or have a 1/4-inch rise for every 1-foot of run towards the termination.
• The arrow on the vent cap should be pointing up
• The Vinyl Siding Standoff prevents excessive heat from potentially warping or melting the vinyl siding material and is required
• If a vent passes through any occupied areas above the first floor, including closets and storage spaces, it must be enclosed. The enclosure may be framed and dry walled / plastered with standard construction materials, but required clearances to combustibles must be maintained.
• Air spaces should not be filled with insulation.
• If a vent passes through an attic space, an attic insulation shield, or a chase enclosure, it must be installed to prevent contact between flue sections and the insulation or other debris.
• For vaulted ceilings a chase enclosure must be constructed for the flue to pass through
• The through the wall thimble should be centered through a square framed opening in wall /  ceiling

Audible Ground Fault Circuit Breakers

 

Audible Ground Fault Circuit Breakers

Audible Ground Fault Circuit Breakers provide multiple levels of protection and alerts for the home owner, and also the home inspector.  Once while inspecting a basement I tested a GFCI with my simple push button tester. It tripped and also tripped a duplex receptacle close to it. A basement freezer was plugged into that receptacle. I heard the freezer turn off when the GFCI tripped. I always reset the GFCI / AFCI receptacle or breaker and then test it again to ensure it is powered. After the inspection (my clients backed out of the transaction based on the home inspection), I received a call from the homeowner telling me that I tripped the GFCI to the freezer and all the meat spoiled. Fortunately the Realtor and my client provided statements that I did reset the GFCI and the freezer was operating when we left the basement. If that GFCI was an audible one, we would have “heard” if it properly reset. Audible GFCI’s automatically self tests to ensure there is power to the GFCI and there is not an issue with the power supply or wiring. They will also not function if improperly wired. Most also have a green light, which gives a visual indication that it is wired properly and has power. Another example is a sump pump. Many home inspectors do not recommend a sump pump is plugged into a GFCI protected circuit. However, an audio alarm will alert the homeowner that there is an issue. Just another way a home inspection is really and education about the house you are purchasing. So how should a home inspector inspect Audible GFCI’s:

 

• When power is interrupted the GFCI will sound an alarm
• A green status light should be visible. This indicates it is wired properly
• Copper or copper clad wiring should be used unless the receptacle is specifically approved for aluminum
• GFCI’s, even with audible alarms should not be used for any type of life support equipment
• GFCI’s installed in wet locations must be Listed and marked as Weather Resistant (WR)
• GFCI’s installed in wet locations should be protected with an approved cover plate or outlet box suitable for wet locations
• The plug face should not be exposed to the weather
• If the reset button will not reset that may indicate the outlet is improperly wired, there is no power, or the GFCI cannot pass its internal test
• Normally GFCI receptacles should not be installed in an electrical box containing more than 4 wires (not including grounds) or cables with more than 2 wires (not including the grounding wire). If these conditions exist, a qualified electrician should evaluate.
• If necessary you can silence the audible alarm by pressing and holding the reset button fully for 3 seconds. Contact an electrician if this happens.
• Any GFCI protected receptacle should have a sticker on it indicating such
• A flashing or solid red light indicates an issue with the GFCI and you should recommend a qualified electrician evaluate
• Recommend your client “test” the GFCI’s monthly by pressing the test & reset button

Inspecting Manufactured Homes

                                               Inspecting Manufactured Homes

Sometimes referred to mobile homes, manufactured homes have come a long way. When I first started my home inspection business and would get a call for a “mobile home” inspection, I would always think; “this is going to be interesting”. These should not be confused with modular construction. Modular construction consists of house components built in a factory with very close specifications. These panels or sections are trucked to the building site and placed on a foundation. Most manufactured homes are normally built in one or two pieces.  If the home was built prior to June 1976, there were no universal building standards required. From 1976 to 1994 manufactured homes were built to a single HUD standard. While better than homes built prior to 1976, there were still some issues with these homes. Since July 1994 every manufactured home has been required to comply with the Manufactured Home Construction and Safety Standards or HUD Code. Part of this code was conformity with certain wind load zones. Any manufactured house I am hired to inspect built prior to June 1976 I warn the owner that it was probably built with no industry standards. I also let them know that homes built prior to July 1994 may also be substandard construction and have other issues that have been rectified since that time. Look for steel tags on the outside of the home that contain build information. What are some of the issues with manufactured homes that a home inspector should be looking for:

 

• Push on exterior walls to ensure they are solid. Movement in exterior walls may indicate rot at the floor or roof areas
• Look for spot spots in the floor
• Wavy floors / unleveled floors
• Sticking / damaged doors and windows
• Older mobile homes used a compressed fiberboard that would rot over time. Newer construction now employ ¾ inch water resistant plywood
• Polybutylene Pipe should be removed
• 100 amp electric service is recommended
• Water stains on the ceiling and walls (you should be able to walk most modern manufactured home roofs)
• Check underneath the home and ensure any pipes are insulated
• Insulation missing or hanging down
• Animal nests
• Foundation blocks should be plumb and not damaged
• The house should be properly attached to the foundation piers
• Deflection of the main beam
• Perimeter blocking normally used for additional support at larger openings greater than 4 feet should not be rotted or damaged
• The house should be properly anchored or strapped to the piers or foundation supports. Manufacturers have specific recommended anchors. Sidewall anchors are located on the long side of the house. End wall anchors are located on the short side of the home. Centerline anchors are located underneath the marriage walls of a double or triple wide home (see diagram).

What is Street Creep?

 

What Is Street Creep?

 

This is a term that I have never used in my home inspection reports. Because we are only inspecting one house and not an entire neighborhood; we would not necessarily be able to determine if the compromised foundation we are inspecting is limited to just that house. However we see many areas that are prone to foundation issues. I know every time I get a call for an inspection in one of these towns, I understand there is a chance there will be foundation issues. Again, we are only inspecting one house, so this term would probably not be put on a report. I had to do a little research on Street Creep

Street Creep, is a slang for movement, shift or expansion in concrete streets or sidewalks. Force or pressure, caused by expansive soils, heavy vehicles, and long term settlement, pushes the street or walkways against the driveway and possibly into the home's foundation producing serious cracks in foundation walls. This problem may be more significant on homes with concrete driveways and attached garages. Homes located at the end of "T" intersections, at the end of cul-de-sacs, and on the outside of a curve are especially susceptible to Street Creep damage. Homes built on hills are more susceptible to creep because gravity will induce paved streets and driveways to "slide" downhill.  Although this is a national problem, it is more prominent in wet areas and areas with expansive clay soils. Expansive soils expand significantly when saturated with water. This expansion is largely due to a chemical attraction of water molecules between layers of clay minerals called Smectites. Dry regions experience the downhill slide scenario. Typically, it is not as noticeable in regions without basements but it still occurs.

 The most common preventative fix for street creep is installing an expansion joint between the slabs to absorb the flex. Expansion joints, also called isolation joints, are used to relieve flex type stresses due to vertical movement of slab-on-grade applications. An expansion joint is simply a buffer made of a rubberized material inserted between two slabs of concrete. Properly installed, it will shrink and expand as the concrete moves, absorbing the pressure and stress of the movement before it starts cracking and shifting foundation walls. The driveway may already have an expansion joint but Street Creep may still occur if it not installed properly. Some individuals recommend installing a vertical flexible buffer joint in the foundation walls. So what are things a home inspector could look for:

• Take a screwdriver and try to tamp it down between the expansion joint and the concrete. You should be able to drive the screwdriver or knife blade down a good 4-5 inches. But, if you're hitting concrete at just 2 or 3 inches, the expansion joint is not installed properly.
• Most contractors will pour the entire driveway and then while the concrete is still wet insert the expansion joint material into the wet concrete. If the depth of the concrete exceeds the width of the expansion material, there can be inches of concrete beneath the expansion material that renders the expansion joint useless. When the slab expands it will push the concrete underneath the expansion material and could then push into foundation walls causing damage to the home.
•  Check expansion joints: If the joints seem unusually tight or compressed -- you might say, "squeezed" or "crushed" – there may be a problem.
•  Check garage floor / foundation walls: If there are cracks in the foundation, outside or in, or if the garage floor slab is pulling away from the garage wall (foundation) this may indicate an issue.
•  Remember, these are just possible indicators of Street Creep. If you see real concerns, note it in your report and refer a structural engineer or a professional foundation repair contractor to further evaluate. 

Inspecting Residential Entrance Ramps

 

Inspecting Residential Entrance Ramps

                                                                

I see many entrance ramps and often times my clients are planning on removing them. Every so often, they plan on keeping them in place. I inspect the physical condition of the materials, stability and visually look at the pitch. However, there are requirements that meld the building codes and ADA requirements. We see this also in other areas of the house. If the house is being build for ADA compliance, the codes may be altered to accommodate these requirements. The guidelines I will outline can also be modified to accommodate the individuals needs; however safety and egress requirements must be maintained. Remember, the remap will probably serve as a means of egress and these requirements also come in to play. The ADA requires a slope of 1:12. So basically if the door entrance threshold is 24 inches off of the ground, you would need a 24 foot long ramp. The maximum height of any section of ramp should not exceed 30 inches. If the height does exceed 30 inches a flat rest platform should be in place before the ramp continues. The minimum width of a ramp between hand railings should be 36 inches. Hand railings must be installed; therefore the deck of the ramp must be at least 42 inches wide to accommodate the width of the hand or guard rail. So what else should a home inspector be looking for when inspecting entrance ramps:

 

• Minimum door opening is 32 inches (clear width = measurement taken between the face of the door and the stop of the frame with the door open 90 degrees)  
• Handrails or guards must be installed if the ramp has a rise more than 6 inches or longer than 72 inches on both sides
• Tops of hand rails should be mounted between 34 & 38 inches above the ramp surface and continuous
• Spaces between the ramp and any wall or surface should be at least 1 ½ inches
• Ramps over 30 inches above ground should employ railings with spindles and a curb stop to ensure the wheels do not go over the sides of the ramp
• Curb guards or barriers shall be at least 4 inches high
• Maximum height of ramp should not exceed 30 inches per run
• There must be a flat landing at the top and bottom of all ramps
• Landings should be at least as wide as the ramp and a minimum of 60 inches by 60 inches
• The minimum headroom for all areas of the ramp must be at least 80 inches
• The floor or ground surface of the ramp run or landing shall extend 12 inches minimum beyond the inside face of a handrail
• Non-slip materials should be used for the ramp surface
• Ramps should be designed to ensure water does not accumulate on walking surfaces

Inspecting Synthetic / Composite Engineered Roof Coverings

            Inspecting Synthetic / Composite Engineered  Roof Coverings

 I’ll never forget the first time I saw a polymer slate roof covering. I first looked with my binoculars, as I always do before climbing. I was struck by the incredible condition of the “slate” tiles on this very old lake house. However when I went up the ladder, I discovered they were a rubberized material. Since then I have seen many. Although the materials used are very durable; it is the installation that can be problematic. There have been some manufactures that have had issues with their product materials in the past. Most of the newer products are very durable and if installed properly should have a long serviceable life. However it is important that other materials including flashing and fasteners are also durable. We normally refer to these coverings as just “composite” because of the many different materials used like: rubber, plastic, and other polymers. It is much more expensive than conventional roofing materials; however the serviceable life, if installed properly is longer. Composite roof coverings will tend to fade or oxidize over time. If you observe different colors / variations in different areas; that may mean that the shingle bundles were not mixed prior to installing. The installer should mix shingles from different bundles to ensure they are properly blended due to color variations. Special installation requirements are recommended for slopes of 2/12 or less. Composite shingles should not be installed on flat roof surfaces. I have outlined broad recommended guidelines. The specific manufacturer installation recommendations should always be referenced. What should a home inspector be looking for when inspecting composite roof shingles?

 

• Snow guard devices should be installed
• ½ Plywood is the minimum thickness required for 16” on center rafters, although 5/8” is recommended. 5/8-inch plywood is required for 20” rafter spacing or greater. OSB is not recommended.
• Minimum 1 ½ ” large head ring shanked roofing nails Stainless steel are recommended
• Nails must be fully covered by shingles and not visible in joints
• Where applicable, only a “pure silicon” sealant should be used to cover up exposed nail heads or to seal joints on ridge caps. The sealant should be color matched
• Every shingle should have 4 nails
• Every cap should have 2 screws
• It is important that the head of the nail not be driven below the top surface of the shake. This may cause leaks in this area.
• The joint between 2 shakes in one course should never be closer than 1 ½” to a joint below or above it.
• A Synthetic underlay is required. Ice / water shield may also be used
• The second course should be installed directly over the starter course, but should project a maximum 1/2" beyond the starter course (drip edge)
• The exposure should be less than 9 inches (7-7.5 normally). (This will vary depending on the shingle size and manufacture)
• A 24” wide W-flashing (heavy gauge) should be used in the valleys
• Stainless steel flashing is recommended