Hot
Water Heater or Time Bomb?
By
Frank G. Ross
One
aspect of a home included in an inspection is the plumbing system,
particularly the hot water heater. In addition to the interior burn
chamber, I include five readily visible items in my check: presence
or absence of the discharge tube, proper ventilation, corroded
fittings, rust on the shroud, and the presence or absence of a drip
pan.
A
key safety feature of the water heater is the pressure and
temperature relief valve. This valve is either on the side of the
water heater close to the top edge or it is on the very top of the
water heater. This P&T relief valve has a very specific purpose. It
is designed to release excessive pressure from the water heater in
case of some kind of malfunction and to prevent the water heater
from exploding. Many times I have seen this valve with a metal plug
screwed into it or I have seen a metal plug screwed into where the
valve used to be. Both cases will make the water heater into a bomb
powerful enough to take out a wall in the house.
The
safest condition is for the P&T relief valve to have a discharge
tube of at least ¾ inch in diameter going from the valve to the
outside of the house or to within a few inches of the floor, not to
an unmonitored crawlspace. The purpose of the discharge tube is to
direct the high temperature water and steam safely away in case the
P&T valve opens. A person can then safely access the water heater
to shut it off. If the discharge tube is too short or not installed,
the discharging hot water or steam would be at face level and not
allow a person to get near the water heater to shut it down. Should
the discharge tube terminate in the crawlspace an opened or leaky
valve could go unnoticed for quite some time. The discharged water
would collect in the crawlspace causing other problems for the home.
At
times a gas water heater is located in a closet inside the home. In
this situation it is critical that the air inlet duct that brings in
fresh air from the outside and the door louvers that vent air from
the closet are never blocked. Proper combustion of the burner can
only occur when the air is allowed to flow freely. Don’t store items
on top of the water heater, possibly blocking off the draft area for
the flue. If any of these are blocked off with stored items there is
a good chance that the water heater can produce deadly carbon
monoxide gas.
Corrosion at the hot and cold water fittings on the top of the water
heater is common. This mineral buildup is an indication of past
seeping or dripping which may only have stopped because of the
corrosion. The underlying cause of the problem is still present and
although an active leak may not be visible today, the chance is good
that a leak will occur one day in the future. In that instance a
plumber may not be able to simply replace the leaky fittings without
damaging the water heater due to the excessive corrosion.
On
occasion rust will be found on the outer metal covering of the water
heater. The presence of rust is not necessarily an indication of a
leak. Frequently the source of the rust is a result of condensation
caused by the combustion process. Water vapor is one of the
predominate byproducts of gas combustion; therefore a thorough check
of the venting system is essential. Many gas-fired water heaters are
returned as leaky when the real culprit was condensation fooling not
only the inspector, but the plumber and property owner as well. In
general condensation is greatest during winter and early spring when
the water temperature entering the unit will be at its lowest.
Seasonal differences in water temperature can vary by as much as 30
degrees F.
It
is important to note that excessive condensation can also cause the
pilot light to go out due to water running down the flue tube onto
the main burner. This situation will cause premature corrosion of
the tank, but not necessarily the water heater’s visible outer
surface.
One
more thing about a water heater, if it is inside the home and there
is not a floor drain near by, it is a good idea to have a drip pan
installed under the heater to catch any drips or slight leaks that
may occur, thus helping to prevent damage to the floor or structure.
Every now and then go look at your water heater. Look for signs of
corrosion, rust, water leaks, drips, and moist areas around pipe
fittings. Know how to shut off the water heater in case of an
emergency. Know where your main water shut off valve is in case of a
major water leak. Keep the water heater closet clear of all stored
items, such as brooms, mops, plastic shopping bags, vacuum cleaners,
etc. The unit has to be able to breathe properly in order to
function properly. If you question whether your water heater is
operating properly call a licensed plumber to evaluate it. And
remember a capped P&T relief valve or missing or plugged discharge
tube is a serious safety problem which should be corrected
immediately by a licensed plumber. Protect your home and family by
defusing the bomb before it has a chance to go off.
Frank Ross is a Certified Utah Home Inspector for Pillar to Post
Professional Home Inspection, a full member of the National
Association of Certified Home Inspectors and a member in good
standing with the Utah Better Business Bureau. Readers may contact
Mr. Ross at (435) 867-6400 or
frank.ross@pillartopost.com or visit
www.pillarposthomeinspection.com
