This blog addresses the lightning or
power surge damage investigations to HVAC and other equipment we are often being asked to provide this time of the year.
Claims dealing with theft of the copper wiring of these units as well as
excessive replacement costs are on the rise.
Lightning or wind storms are two of the
most obvious sources of a power surge, but there are other causes as well. A lot of power surge damages are caused by electric power line
failures, transformer problems, improperly installed generators, cycling of air
conditioning units, generators, and other motors, to name a few.
In addition to lightning, the
classic example is a windstorm that causes a tree limb to contact a power
line. The breaker at the electric substation
senses that there is a problem somewhere on the circuit, and opens momentarily
in an effort to blow the closest fuse and isolate the fault. This is what we have all experienced during a
storm when the lights momentarily blink off and on. When this occurs all people on the circuit,
which could number into the thousands, experience the momentary blink. If
an air-conditioner or heat pump is running when the power goes off, it should
have a time delay relay to prevent the compressor from coming on right away. If the air compressor fails to turn off and
tries to re-start under pressure, it will cause premature failure or burnout of
the air conditioning compressor. In this very common case, the
cause is most likely the failure of a safety feature of the compressor
preventing excess electricity from entering the air conditioner
compressor.
Typical HVAC systems or “split
systems”, also known as central air conditioning systems are comprised of three
main components: the interior unit that
consists of an air handler unit, the air filter, a gas furnace or electric heat
strip and an evaporator cooling coil or heat exchanger; an exterior unit that
consists of a refrigerant compressor, condenser fins/coils and a cooling fan
that circulates outdoor air across the condensing coil to cool it; and the air
distribution duct system. The
refrigerant used with a typical split system is either R-22 or R-410A, although
other refrigerant types also exist. After
2010 no AC can use R-22 refrigerant due to the Clean Air Act of 1990.
Figure 1: Dirty Condenser Unit that failed. The unit seized due to the clogged coil
(right photo) and damaged contactors and capacitor. The contactor terminals were heavily rusted
and it stuck, leading to compressor overload.
This is typical failure mode based on our investigations. The insureds and the HVAC techs always claim
that power surge caused the failure.
Figure 2: Central air conditioning system compressor, condenser fins/coils and the removed cooling fan (left, placed on the
grass) for inspection of the unit. Note
the dirty condenser fins. The dirty fins
limited the amount of air for cooling, which led to the overheating and failure
of the air compressor. No lightning or
power surge caused this damage.
Hi-tech damage claims
are initially categorized as lightning losses or power surge losses. Based on the
results of our investigations, very few (less than 1 percent) of the reported
lightning strikes or power surges are caused by lightning or windstorms. Most appliances fail due to refrigerant leak that led to
compressor failure, poor installation, lack of maintenance (dirty air filters
or dirty condenser coil) or old age (wear & tear) and there may not be any
basis in fact for a lightning claim. Air conditioning compressors are particularly
susceptible to failure due to poor installation procedures and lack of
maintenance. Next to refrigerant leaks, compressors
represent the next highest rate of failure of any HVAC component. Out of 21 of lightning strike claims we handled last month, 14 of
the claims were a result of a lack of maintenance that resulted in the failure,
5 were misdiagnosed and were repaired on site, 2 had mechanical damage but were
under manufacturer’s warranty; none of
them was caused by lightning. Nine times out of ten the HVAC technician will
tell the insured that he had a "big" power surge; the tech then goes
on to recommend replacement of the entire system, including the air
handle.
Commercial insureds with
3-phase equipment that isn't properly protected are susceptible to
loss-of-phase damage. This condition can
occur, for example, if a vehicle strikes a pole and causes a fuse to blow on
one of the phases but not the other two. The insured is now in a single-phase condition
until the utility can get a lineman dispatched to replace the fuse. HVAC units, elevator motors, and air
compressors without loss-of-phase protection to automatically shut them down
can all be damaged.
More often than not, the
only evidence we find in lightning damaged equipment is a burnt odor and
sometimes a capacitor or a small resistor or diode that is burnt through. See Figure 3 for a damaged capacitor following
high temperatures and pressures in the system.
The capacitor failure was not caused by a power surge. The life of a capacitor is typically 5
years. Run capacitors are used on 1-phase
compressors. The run capacitor remains
in the circuit all the times to help improve the energy efficiency of the
motor. If a run capacitor fails, the
motor will draw about 10% too much current and may over heat. If the run capacitor looks over heated or
distorted it has probably failed and must be replaced. If the insured fails to change the capacitor,
then the compressor will be damaged.
Figure
3. Damaged dual run (fan and the
compressor) capacitor of the exterior condenser unit. Note the rusted terminals and the bulging at
the top. The top of the capacitor must
be flat; this one is bulging like a shaken pop can. If the capacitor is not replaced immediately,
it will lead to compressor overheating and failure.
These types of claims involve several steps, to insure prompt and
cost-effective investigation of the damage.
First Step- Verification of the Cause of the Damage
The first step involves the verification of the cause of the
damage: was it power surge, direct lightning strike, wear & tear, loss of
refrigerant, mechanical failure, incorrect installation, failure to
inspect/maintain, etc. Knowing what caused a loss
to occur is the first step in determining whether or not it will be covered
under the insured’s policy. We work with
all parties (insured, independent adjuster, public adjuster, insurer, reinsurer,
etc.) to identify what happened, why it happened, and if any product recalls or
outside factors (such as lack of maintenance, known defects, or wear and tear)
contributed to the loss. We identify the
distinguishing characteristics of the damages to determine if an electrical
event was a viable cause for the loss.
Once verified, we work with multiple lightning activity resources, local
weather reporting stations for windstorms, and electric utilities to
substantiate any reported lightning activity or power irregularities, damaged
utility equipment, etc. on the date of loss.
Complemented by STRIKEnet® Lightning
verifications and power company incident reports, our assessment reports
provide precision and accuracy in resolving small to more complex claims. We had not a single insurer complaining to us
for spending $95 to obtain the STRIKEnet® Lightning report. Final reports are made as per the clients’
requirements and they can be few pages long to more comprehensive. The reports include replacement cost, repair
cost, restoration as well as salvage options when applicable.
Second Step –
Determine the Actual Damages for Repair
The second step involves the establishment of the actual damages
for repair (if feasible) of the damaged equipment.
Third Step-
Review of Repair Estimates and Invoices, LKQ, RCV/ACV
The third step involves the review of repair estimates and
invoices provided by the insured’s contractor for reasonable and customary
material and labor charges. This step
also includes Like Kind and Quality (“LKQ”) analysis of the HVAC unit
reportedly damaged at the insured property to determine the appropriate
Replacement Cost Value (“RCV”) or Actual Cash Value (“ACV”). There
is an increasing pattern of overstating the amount of actual damages to the
HVAC system. We often see recommendations
from vendors to replace the entire system, including the air compressor,
condenser fins, evaporator coils, and so on, when all that is needed to do the
repairs is replacement of a capacitor.
Very rarely there is need for such wholesale replacement.
TYPICAL PROBLEMS ASSOCIATED WITH HVAC SYSTEMS
Below, we provide few typical Problems Associated with HVAC
Systems during the investigations to HVAC and other equipment.
During
the first step we interview the insured and any witnesses to the damage. Witnesses typically tell us that they heard a
sound and that they saw sparks and smoke coming out of the equipment; at other
times they state that the compressor worked just before the storm and then it
stopped working. Even the HVAC repair
technicians many times state that the oil was black, or that the insulation was
burned or the terminal was blown. They
then assume that a lightning hit the unit without performing an investigation
into the actual mode of failure.
If the motor
windings are electrically sound, then the compressor was not damaged by a surge
voltage or lightning stroke. However, a
mechanical failure (a broken valve, worn bearing, blocked coils, rusty
terminals, etc.) may have been the cause of an electrical failure. On the other hand, an electric failure rarely
causes mechanical failure of the equipment.
The often heard statement “the
blackened acidic oil indicates the motor was damaged by a lightning stroke” is
also false. The compressor oil will
blacken and form an acid only when the oil is exposed to excessive heat for an
extended period of time. Overheating of
the motor-compressor unit is the most frequent symptom of system problems. The heating and charring of motor winding
insulation causes a chemical breakdown that combines with the oil. This will then blacken the oil and form an
acid. When a motor fails as a result of
a surge voltage or lightning stroke, the oil is normally in a like-new
condition. A surge voltage or lightning
strike occurs in an extremely short period of time which does not allow enough
time for the oil to blacken and turn acidic.
Thus, if the
refrigerant oil is burnt or acidic there is a good chance that the damage is not
lightning/power surge related. It should
also be noted that burnt or acidic refrigerant oil does not require the
replacement of the entire system as is commonly stated.
Another misconception about
lightning is that it can damage a motor-compressor unit even if the equipment
is turned off during a storm. If a surge
voltage or lightning stroke has enough voltage to gap the open contacts on the
main contactor, then there will be damage to various other components in the
air-conditioner and possibly to the building’s entire electrical system. Therefore, the insulation melts and could possibly
start a fire before the air-conditioner is damaged.
We
often see problems associated with contamination of the refrigerant, especially
the mixing of the R22 with the R410 refrigerants. Many times the air flow through the
condensing coil has become clogged with debris;
this will cause overheating and subsequent failure of the air
compressor.
Other problems
include, but are not limited to, corroded terminals, lose terminal connections,
high refrigerant pressure, refrigerant leaks, failed electronic controls and
sensors, worn out internal components of the compressor, bad electric and
mechanical installation, failed fans, a short
to ground in the fan motor or a short to ground in the fan motor wires that
lead to the motor. and
so on. Over time, low refrigerant levels can
cause overheating and premature failure of the compressor, often requiring
complete replacement of the compressor or the entire condensing unit. The electronic controls and sensor that cause
your air conditioner, fan and condenser to kick off and on properly are often
the first components to go. Sometimes these sensors are merely knocked out of
position causing the air conditioner to cycle constantly or behave erratically.
Terminal Pin Problems
Problems
with terminal pins are also a common cause of air-conditioning compressor
failure. See Figure 4.
If the terminal pins are loose or “blown” on a compressor, then the
compressor will need to be replaced.
However, pin failure does not indicate damage by a surge voltage or lightning
stroke. The most likely cause of a
burned electrical terminal on a compressor is a loose electrical connection.
This loose connection causes a buildup of heat and results in a burned
terminal.
Rusty
terminal connections also create the same low voltage condition as loose
terminal pins. When a low voltage condition occurs, the motor will slowly
fail. This low voltage condition also
causes even higher heat to develop at the terminal pin connection causing even
greater rust. This results in more
disintegration of the connection and causes low voltage to be supplied to the
motor which eventually causes the motor to fail or the terminal pin(s) to
become dislodged.
It is
possible to have damaged pins due a lightning strike, but this is limited to
situations where the lighting strike damage is severe. In these cases there is
a lot of other evidence of a lightning strike. The condenser fan motor or other
electrical components of the system will have been damaged. The wires are burnt and there is evidence of
arc marks to the cabinet where the wires run close to the cabinet. There is also considerable damage to other
motors and appliances as well as to the electric panel.
Figure 4.
Burned compressor plug due to defective (loose) connection to the
compressor. Initially the HVAC techs
claimed that this was caused by power surge.
However, there were no other evidence (storms, lightning, utility
reports, etc.) to support that claim. A
power surge big enough to do that damage to the compressor plug would have damaged
the whole control section, capacitor, contactor and most of the wiring. No such evidence was observed.
In case of any equipment or HVAC
compressor-related problem, identify the root clause, without jumping to the
conclusion that the equipment was damaged by lightning or power surge. If the compressor is replaced without
attending to the root cause, the replaced compressor surely will also fail.
Metropolitan Engineering,
Consulting & Forensics (MECF)
Providing Competent, Expert and Objective
Investigative Engineering and Consulting Services
P.O. Box 520
Tenafly, NJ 07670-0520
Tel.: (973) 897-8162
Fax: (973) 810-0440
E-mail: metroforensics@gmail.com
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