2019 AHR Expo

Just returned from attending the Air Conditioning, Heating, and Refrigeration Expo held in Atlanta Georgia.  Some of the biggest names in the HVAC industry, such as Carrier, Trane, and York, were in attendance.  Along with cooling and heating equipment, those manufacturers that make specialty items such as boilers, compressors, piping, controls, motors and refrigerants were also in attendance.  Visitors, as well as vendors, came from all over the world to see new product lines as well as to showcase their products.  The trend, as has been the case for several years now, is to make machines more energy efficient.  Incorporating electronics to measure different parameters such as temperature and pressure, is now routinely done.  Depending on the type of equipment, manufacturers are also offering options on how the equipment is monitored.  Some owners prefer to let their on-site personnel keep up with the operation of their equipment while others are connected by internet to a servicing agency.

No matter how efficient or how well built a machine is, it will eventually fail.  Hopefully, when it does, there won’t be any property damage or personal injury.  But if there is,  the information collected during the Expo on various products will be invaluable in helping to determine the cause of failure and subsequent damage.  More specifically, the literature can be used to help identify a machine by model number, determine the pressure limitations, or establish the power requirements.

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Beware of Acucraft Wood-Burning Fireplaces

Not many people know that Underwriters Laboratories certifies manufactured fireplaces.  Underwriters Laboratories is a testing organization that tests and certifies many products for use in residential, commercial and industrial applications.  The UL label is a consumer’s indication that a product has been tested and found safe for use by the consumer.  Specifically, manufactured fireplaces have to meet the requirements of UL 127 before certification is approved by Underwriters Laboratories.  In an effort to safeguard life and property, codes organizations, such as the International Mechanical Code, have incorporated the standard.  Municipalities that adopt the International Mechanical Code use the code as a means to determine if a mechanical installation is safe.

A situation was recently brought to our attention involving an Acucraft manufactured wood-burning fireplace.  The fireplace was purchased for $9000.00 for use in a renovated bonus room.  During the renovation, a structural issue arose that required a building inspector to visit the property.  Upon doing so, it was discovered that a permit for the installation of the fireplace had not been issued by the city.  Upon further inspection, the mechanical code inspector discovered that the fireplace did not meet the code requirement for the fireplace to have been certified according to UL 127.  As a result, work on the project was halted.  The useless fireplace is shown below.

 

Acucraft Uncertified Wood-Burning Fireplace

 

Acucraft was later contacted and verified that their wood-burning fireplaces were NOT subjected to any testing protocol such as UL standard 127.  As a result, the homeowners are left with an expensive fireplace that the local codes department will not approve and therefore cannot be used.  Acucraft wood-burning fireplaces can be seen on their website at www.acucraft.com.  It is understood that Acucraft does not sell its products through a retail network but instead, sells directly to the customer.  Before buying a product, be sure that the product meets applicable code requirements in the local area where it will be installed and that the installing contractor obtains the necessary permit for the installation.

Watch Those Connections!

Some appliances such as stoves and dryers, do not come with line cords when the appliances are purchased.  As a result, consumers have to make separate purchases in order to use their new machines.  When attaching the cords to the appliance, pay close attention to the way the manufacturer requires that the line cords are connected.  For many do-it-your-selfers, this is no big deal.  It shouldn’t be a big deal for a professional electrician either.  However, we are all human and subject to making mistakes.  Case-in-point: the following dryer fire.  Although minor as residential fires go, the damage could have been much worse.  The photographs shown below illustrate how the manufacturer called for the installation of the line cord and the subsequent way, the cord was connected.

The manufacturer’s schematic drawing shows how the “hot” (red and black wires) lines of the line cord were to be attached to the L1 and L2 terminal block terminals.  The common line or white wire was to be connected to the N terminal on the terminal block.  Lastly, the green wire or earth ground, was to be connected directly to the appliance housing.  The photograph below shows how the white and black wires were reversed on the terminal block.

 

 

Since the common and earth ground points are electrically the same point, the dryer was, in effect, energized through the housing.  Anything in contact with the dryer housing, such as the exhaust duct, will also become energized.  Dryer ventilation ducts are usually coils of steel wire wrapped with a thin layer of vinyl or aluminum material.  As current flows through the steel wire, the external covering is heated.  If not stopped, the heat will cause the covering to melt and possibly ignite.

Happy Holidays!

R.j. Hill Consulting would like to wish everyone a Happy Holiday Season.

Wheel Separation in 2016 Ford Taurus-Possible Recall?

One of our recent investigations involved the separation of the left front wheel and whether it was the cause of a two vehicle accident.  The scenario was such that the driver made a right hand turn and felt the vehicle pull to the left.  The driver also stated that he lost control and hit a parked car.  Typically, in these types of impacts, the wheel is pushed into the wheel well.  But, in this case the wheel separated from the car.  Upon examination, it was determined that the threaded connection holding the strut to the frame was broken as well as the clamping part of the lower steering knuckle.  The failed parts are shown below.

DSC01046

Failed strut threaded connection

DSC01042Clamping part of lower steering knuckle found broken

It should be noted that the steering arm tie rod was also bent and broken and that a stabilizing rod connected to the strut was separated from its knuckle joint.  If either of these connections is broken, then the wheel will become unstable.  Are there other instances where drivers have experienced similar situations?  Is this a condition that warrants a recall?

Combined Heat and Power

I just completed a webinar refresher on combined heat and power systems.  If you don’t know or have never heard of a combined heat and power system just picture a jet engine that doesn’t move.  The heat coming out of the exhaust is used to make steam.  On the other end, the rotating fan is connected by shaft to a generator and produces power.  Another type of system uses a boiler to make steam.  The waste heat from the flue gas is reclaimed using a heat exchanger to make additional steam.  The primary steam is then routed to a turbine which in turn, turns a generator and makes electric power.  The secondary steam is sent to whatever process will utilize the steam, such as an absorption chiller, for air conditioning.  Most CHP systems are well suited for industrial applications where large quantities of steam and power are required. However, smaller systems are also made and suited for light commercial applications.  Advertised efficiencies run between 70 and 75% depending on manufacturer.  These machines are fairly reliable and so, in the course of my practice, I have only encountered one instance where a gas turbine (jet engine) failed to perform as required.  Two engines were installed in a university setting and used to provide steam and power to various campus buildings.  Shortly after installation, it was noted that one of the gas turbines was not performing as warranted by the manufacturer.  After review of the design of the entire system, it was determined that one of the gas turbines was not performing according to its design specifications. The claim was finally resolved when the manufacturer agreed to replace the machine with a new gas turbine.

Veteran’s Day Appreciation

veterans day desert

The above photo of a special dessert was given to me after a Veteran’s Day dinner at a local Restaurant.   While I am very appreciative of the gesture, I would also like to say thank you to those who are appreciative of those of us who have proudly served.

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