Water Heater Backdrafting

Backdrafting at a water heater is a common defect identified during home inspections, and it’s almost always a condition that the homeowner or occupant is not aware of.  This happens when the exhaust gases from an atmospherically vented water heater spill out into the room, rather than safely leaving the house through the vent.  Exhaust gases contain carbon monoxide and high levels of moisture, so this is always a condition that should be corrected.

An atmospherically vented water heater is a type with a draft hood, which relies on gravity to get the exhaust gases out of the home.  Exhaust gas is hot and therefore lighter than the surrounding air, which is what allows it to rise up the vent and out of the house.  These are very simple devices that require no electricity to operate, however, this isn’t a very reliable draft method.  Today I’m going to share some clues that could indicate a problem with a water heater drafting properly.

Backdrafting exhaust gases can condense at the top of the water heater tank.  Over time, this corrosive condensate will begin to corrode the top of the tank.  A leaking shutoff valve can also cause corrosion at the top of the tank, but that type of corrosion is easily distinguishable back corrosion caused by backdrafting because the worst area will be located directly below a valve.

If you can see condensation at the top of a water heater tank, you’re basically watching the water heater backdraft.  The photo below shows moisture, rust, and melted plastic at the top of the water heater.

The vent connector at a water heater needs to pitch upwards towards the vent, and should ideally not have any quick turns, especially right at the draft hood.

If you find these types of clues, there might be a problem with the water heater drafting properly.

I have several different tools that I can use to check for proper draft at a water heater if I’m feeling fancy, but there’s really no need.  If I want visual evidence to put in an inspection report, I usually hold a mirror up the draft hood and take a picture of the mirror getting fogged up. 

Any water heater backdraft condition should be evaluated and corrected by a qualified professional.

Top 4 issues found during home inspections

Buying a house is the biggest investment most people make during their lifetimes. Whether it’s a newly built home or a fixer-upper, having a certified home inspector evaluate its condition is highly recommended before committing to a purchase. Here are the top four common causes of defects inspectors regularly come across during home inspections.

Water Damage

Moisture and drainage issues can lead to dry rot, foundation problems, structural damage and toxic mold in a home. Some common causes include:

• Grading that slopes toward rather than away from the structure

• Roof leaks from missing shingles, improperly installed flashing or failed sealant around penetrations

• Leaks from connections to kitchen and bathroom fittings and fixtures

• Tree roots invading and clogging lines, causing water to back up into the home through the drains

• Gutters clogged with leaves or other debris that overflow and damage the stucco or siding

Faulty Wiring

Faulty electrical wiring is a common cause of house fires, especially in older homes. Home inspectors often find the following dangerous conditions:

• Exposed wires or improperly spliced connections

• Wrong size breakers in electrical panels that allow circuits to become overloaded

• Overloaded circuits that cause wiring to heat and its insulation to melt away

• Improperly wired receptacles where the black hot wire and neutral white wire are reversed, which can be a shock hazard

Mold

Surface mold in poorly ventilated bathrooms is common and usually not harmful. Black mold in basements or crawl spaces, however, is a serious problem. Here are some of the concerns associated with black mold:

• Black mold can cause asthma and other serious health problems

• Black mold can be expensive to remedy

• Although it can be removed, ensuring it won’t return can be difficult

• Black mold almost always indicates a serious underlying problem, such as cracks or leaks in the foundation

Water Heater Issues

Whether it’s heated by gas or electricity, water heaters are among the most neglected items in a home. Signs that a water heater needs replacing include the following:

• Rust on the heater’s bottom surface and lower edge indicate the heater is on the brink of failing and replacement is overdue

• A stuck or jammed TPR valve can cause the water temperature and pressure inside the tank to exceed safe levels, potentially causing serious personal injuries from scalding and property damage from an explosion

• Blackened areas near a gas water heater’s burner usually result from improper combustion, which can be a sign of deadly carbon monoxide emissions

• A water heater more than 10 years old is at risk of failing, and unless it’s situated in an area where flooding won’t cause serious damage, it should be replaced

The Role Of Expansion Tanks In Your Water Heating System

When a water heater is connected to a closed system, an expansion tank must be installed to prevent excessive pressure in the water. To help understand what this is all about, please read on.

OPEN SYSTEMS
When a water heater fires up, the water in the tank expands. When this happens, where does the water go? Right back out the cold water inlet, all the way back to the water supply coming into the house. The municipal water supply for the house acts as a gigantic expansion tank… and nobody notices. This is illustrated in the diagram to the right.

CLOSED SYSTEMS
What happens when a one-way valve, or check valve, gets installed on the water supply piping for the house? The water has nowhere to go. As the water heater heats the water, it expands, which builds up pressure. When the pressure builds up enough, the temperature and pressure relief valve on the water heater simply does its job. It relieves the excess pressure by leaking a little bit of water.

This doesn’t happen every time that a pressure reducing valve or check valve is installed, but there may be other problems that show up in the house, such as the toilet fill valves randomly re-filling toilets, or faucets chronically dripping.

In Texas, it’s rare for a check valve to be installed on the water supply line for the house, but it’s fairly common to have a pressure regulator installed. The problem that these regulators can create is that they will act as a check valve; they’ll allow water into the home, but they won’t allow water back out. This creates what is called a ‘closed system’.

EXPANSION TANKS
When a closed system exists on the water distribution piping in a home, an expansion tank needs to be installed somewhere on the plumbing system. This is a fairly simple and straightforward fix; an expansion tank uses an air bladder which is compressible which gives the water somewhere to go when it expands, and the temperature and pressure relief valve on the water heater will stop causing problems.

REQUIRED OR JUST A GOOD IDEA?
As of 2018, the International Plumbing Code 607.3 requires an expansion control device whenever a check valve or pressure reducing valve is used in the water supply.

Where a storage water heater is supplied with cold water that passes through a check valve, pressure reducing valve or backflow preventer, a thermal expansion tank shall be connected to the water heater cold water supply pipe at a point that is downstream of all check valves, pressure reducing valves and backflow preventers. Thermal expansiontanks shall be sized in accordance with the tank manufacturer's instructions and shall be sized such that the pressurein the water distribution system shall not exceed that required by Section 604.8.

How Drone Photography Can Help Sell A Home

Photography is key when selling any property.  Professional pictures are the best way to show off your home’s features and immediately grab buyers’ attention. But, depending on the type of property you have, traditional photos may not be adequate. More and more, sellers and their REALTORS® are using drone photography to take their marketing to the next level. 

An aerial shot of a property, as opposed to a simple street-level shot, can give depth and dimension, and also provide a view of a home’s surroundings – a backyard pool, a nearby creek, a neighborhood park, etc. With a drone, you have a virtual tripod that you can use to get camera shots at unique heights and angles.

Prior to the use of drones, aerial shots were only possible by hiring a helicopter, which is not only time consuming, but also very cost prohibitive. Now, it’s possible for a licensed remote pilot to easily capture aerial pictures and videos and send them to an agent’s inbox in just a few hours. Prices vary depending on the project, but aerial packages for small residential properties typically range from $100-$500. 

This technology is becoming increasingly popular and is almost expected on large, unique properties and higher end homes. If a property sits on a large parcel of land, or has a barn, farmlands, outbuildings, a pool, etc… details can get lost with the limitations of standard photography. 

In addition to this, drone photography can often provide sweeping views to give potential buyers great perspective of how a home is positioned in relation to desired amenities, nearby schools and landmarks.

While anyone can purchase a drone online, there is much more to getting great real estate footage. For best results, REALTORS® should hire local professionals who are licensed to fly drones, are insured, and have experience with shooting and editing aerial photography. There are strict rules and regulations to consider, so working with a professional is critical. 

Today’s buyers are more interested in pictures and video, They don’t want to read about a home’s features, they want to see them. As they say, you only get one chance to make that first impression, and professional photography and drone technology can give you that edge. 

Drone Land Survey Accuracy

Modern commercial drones have made mapping any area or an object a matter of few minutes or hours, instead of the typical days or weeks it used to take before.  A small commercial drone can now let a qualified operator achieve survey-grade accuracy in a photogrammetric map or 3D model.

But just how accurate can these surveys be? How is accuracy defined and measured in these drone based aerial surveys?

SURVEY ACCURACY VS. PIXEL SIZE

One of the most important parameters of a survey is the spatial resolution. Spatial resolution is described as GSD (Ground Sampling Distance). In literature, it is defined as the distance between two consecutive pixel centers measured on the ground. In practice, it is simply the size of the pixel in the field.

The GSD depends on the parameters of the camera being used (mainly camera resolution and focal length) and the flight altitude. For example, to achieve 1 cm (3 inches) pixel size using a smaller professional drone like the DJI Phantom 3 Professional or DJI Mavic Professional, you will need to fly at an altitude of 25 m. Using a larger professional device like PrecisionHawk’s Lancaster 5 will let you achieve 1 cm GSD at 60m.

RELATIVE ACCURACY VS. ABSOLUTE ACCURACY

Relative accuracy is the measurement of how objects are positioned relative to each other in a reconstructed model (Orthophotomap, Digital Surface Model or 3D point cloud). Absolute accuracy refers to the difference between the location of the objects on the reconstructed model and their true position on the Earth (or a geodetic coordinate system). For most small areas and simple use cases, the relative model works just fine. It accurately measures distances, volumes and height differences and allows for operations like applying vegetation indexes to your data.

However, if professional photogrammetric survey documentation is needed, or if the data is to be combined with other data layers (e.g. GIS vector data) or do any operations with geographic coordinates in a geodetic reference system, the absolute orientation of the reconstructed model will need to be determined by using Ground Control Points or GCPs. They help to increase the accuracy of your drone survey and allow you to fit the model in a geodetic coordinate system. These points must be measured by a land surveyor using professional equipment, such as the RTK GPS or a Total Station.

WHAT RELATIVE ACCURACY CAN BE ACHIEVED IN DRONE PHOTOGRAMMETRY?

When it comes to relative accuracy (Surveys without GPCs), the literature says you can expect an error of 1-3 times the pixel size for a correctly reconstructed model, both horizontally and vertically. This means that for a 2 cm GSD, one should be able to achieve the accuracy in the range of 2-6 cm.

CONCLUSION

The accuracy requirements of any survey depend on its final application and the use case. In many cases, 30 cm (1 foot) will be more than enough, while on other projects 2 cm is the maximum acceptable error. Using a small professional drone without GPCs placed by land surveyors can still provide a highly accurate product for many standard use cases.

About Ground Fault Circuit Interrupters (GFCIs)

What is a GFCI: The ground-fault circuit interrupter, or GFCI, is a fast-acting circuit breaker designed to shut off electric power in the event of a ground-fault within as little as 1/40 of a second. It works by comparing the amount of current going to and returning from equipment along the circuit conductors. The GFCI will “sense” the difference in the amount of electricity flowing into the circuit to that flowing out, even in amounts of current as small as 4 or 5 milliamps.

Purpose: A ground fault circuit interrupter can help prevent electrocution. If a person’s body starts to receive a shock, the GFCI senses this and cuts off the power before he/she can get injured.

Where should GFCIs be used: GFCIs are generally installed where electrical circuits may accidentally come into contact with water. They are most often found in kitchens, bath rooms and laundry rooms, or even out-doors or in the garage where electric power tools might be used.

How should a GFCI be tested: Whether you have a receptacle or circuit breaker GFCI, pushing the TEST button should turn off the power to the circuit. For the receptacle-type GFCI, pushing the TEST button should cause the RESET button to pop up. (Remember to push the RESET button to re-establish power and protection.) For the circuit breaker-type GFCI, pushing the TEST button should cause the handle to move to the tripped position. (Remember to reset the handle to re-establish power and protection.)

When should GFCIs be tested: GFCIs should be checked monthly to determine if they are operating properly. A portable GFCI should be used out-of-doors with various electrical power tools (i.e., drills, mowers, trimmers) and should be tested before each use!

Read more about GFCIs from InterNACHI here https://www.nachi.org/gfci.htm