Getting Hot After Heating Systems:
Cold weather always gets here before you know it
so invest a little time in checking your heating
equipment before you become totally dependent on
it. Do not attempt to adjust or repair anything
unless you are absolutely certain you know
exactly what you are doing. Looking and checking
is one thing, adjusting or repairing is quite
another. Most homeowners should leave
adjustments and repairs to professionals.
What Kind of System Do You Have? If your house
has grilles in the walls or floors you have an
air system with a furnace. If you have radiators
or baseboards, you have a water system with a
boiler. (Furnaces heat air while boilers heat
water.) The vast majority of air or water
systems are fueled with gas.
Gas Furnace/Boiler:
Make sure the appliance is deactivated prior to
any examination. Turn off the service switch
attached to the furnace or boiler or in its
absence, turn off the circuit breaker or take
out the fuse controlling the furnace. Next
remove the access covers. There are usually two
for furnaces and just one for boilers. (They can
usually be lifted slightly and then pulled
straight off.) Once the access covers are out of
the way trace the gas pipe into the front of the
boiler/furnace and observe where several other
pipes tee off this pipe and extend horizontally
back into the furnace itself. These are the
flame tubes. Shine a flashlight along them to
see if any rust is covering the little holes
where the gas comes out. A little rust is
expected but if there is enough to clog gas
ports or cover a burner, it will need to be
vacuumed out. You can do this yourself but you
will have to turn out the pilot light and
relight it when you are done, following
manufacturer's instructions. Naturally you will
choose a relatively warm afternoon and avoid
working until the furnace has cooled down.
WARNING:
Significant quantities of rust over burners can
prevent the gas exiting the flame tubes from
quickly igniting at the pilot and in severe
cases can cause a minor explosion when a gas
buildup finally reaches the pilot light. If in
doubt at all, call a professional serviceman.
Air Handlers: The air handler is usually behind
the lower panel. If it is beltdriven by an
outside motor, push on the belt with your
finger. You should get about 1/2 to 3/4 inch of
play. A significant difference either way merits
an adjustment (usually with a screw on the motor
housing or on the motor pulley.) Look for
cracking or shiny sides of the belt, indicating
wear and age. Replace the belt if either symptom
appears. Look for little cap covered tubes on
each end of the motor and the air handler. These
are lubrication cups and each cup should receive
2 or 3 drops of 20 weight machine oil about
every 3 months of operation.
Circulating Pumps:
Boilers often have circulating pumps which serve
to help the water quickly flow through the
boiler and around the house. These usually are
red or green in color and look like motors
nosing up against the pipe that enters the
bottom of the boiler. These need to be
lubricated during the heating season. Use 20
weight machine oil (3 or 4 drops) in each lube
cup. You will find one on each end of the drive
motor and one on the pump itself.
Check The Flames:
Next observe the burners in operation. (Be sure
to replace the air handler access door on
furnaces first.) Turn up the thermostat and
reactivate the service switch or circuit breaker
or fuse. The furnace should quickly light along
the flame tubes and within minutes, the air
handler should come on in furnaces. Once this
has happened, observe the flames on the flame
tubes. Flame should be coming from all of the
gas ports and it should be blue in color. Yellow
flames indicates an excess of air (the appliance
will operate inefficiently) and an adjustment is
called for. (A little yellow at the tips of
flames is quite common but a lot of yellow in
the flame body indicates a very inefficient burn
which will release larger quantities of toxic
gasses.) A glowing reddishorange color along the
flame tubes indicates remaining rust
accumulations which should be vacuumed out.
Major Trouble: In furnaces with the air handler
operating, a fluttering of the flames along a
flame tube accompanied by large amounts of
yellow coloring can mean a crack or hole in a
heat exchanger. This is major trouble and should
be verified by a professional. Call the gas
company. Be prepared for them to turn the gas
off to your furnace if they discover a defective
heat exchanger. Younger furnaces should have the
heat exchanger itself replaced while those 15
years and older are good candidates for complete
replacement. You can double check the yellowing
by observing the flames when the burners first
come on without the air handler yet in
operation.
The Flue:
With the furnace or boiler operating, place your
hand several inches from the vent hood. (The
flue pipe on gas appliances is not a solid
connection. It usually has a cone shape where it
joins the top of the boiler/ furnace or an
access where it joins the top of the
boiler/furnace or an access slot under the flue
pipe on the forward part of furnaces. This
opening is intended to allow air into the
chimney to cool it somewhat and to allow the
occasional down drafts in the chimney to escape
outside the appliance without extinguishing the
pilot light.) If heat is pouring from this area,
it usually means that the flue or chimney is not
drawing properly. You may have a birds nest or
loose brick down in the chimney. In any case,
the appliance should not be operated like this
since toxic combustion fumes are pouring into
the house. Call a serviceman.
Gas: If
you smell gas around the furnace/boiler,
especially if the pilot is lit, call the gas
company.