MANAGEMENT OF HEATING PLANTS
The following instructions on the care and management of steam and
hot-water heating plants is printed with permission of the American
Radiator Co. They were prepared as a guide to the successful operation
of the Ideal heating plants but apply with equal force to other plants
of a similar character.
=General Advice.=--No set rules can be given for caring for every
boiler alike--chimney flues are not alike--some have strong draft,
some are average and some are weak. There is much more difference in
the heat-making qualities of coal than is commonly known, and it is
important that the right size coal for the draft be used. These rules
apply to most all fuels. A little trying of this way or that way of
leaving the dampers (when regulators are not used) often discovers the
better way. It is well to vary from the rules a little if any of them
do not seem to bring about the best results.
With good, average chimney flue draft and the right kind of fuel, these
rules will govern the large majority of cases.
=The Economy of Good Draft.=--In many cases a boiler with sluggish
draft will burn more coal than a boiler with good draft. In the first
case the fuel may be said to “rot”--in lacking air supply the gases
pass off unburned. The “nagging” which a boiler has to take under these
conditions increases the waste of fuel. A boiler under sharp, strong
draft maintains a clear intense fire and burns the gases--getting the
larger amount of heat from the coal.
=General Firing Rules.=--
1. Put but little coal on a low fire.
2. When adding coal to the boiler, open the smoke-pipe damper (inside
the smoke pipe) and close the cold-air check damper. This will make a
draft through the feed doorway inward and prevent the escape of dust or
gas into the cellar when the feed door is open to take fuel. Put these
parts back to their regular places after feeding.
3. When it can be done, in feeding a large amount of coal (as for
night) leave a part of the fire or flame exposed, so that the gases may
be burned as they arise.
4. When a regulator is not used, learn to use the dampers correctly
and according to the force of the chimney draft. Learn to use cold-air
check damper. Often, when closing, the ash-pit draft damper does not
check the fire enough; opening the cold-air check damper will check it
about right. Increasing or lessening the pressure of a steam boiler
must be done by changing the weight on the regulator bar.
5. Carry a deep fire or a high fire; let the live coals come up to the
feed door--even in mild weather when from 4 to 6 inches of ashes stand
on the grate.
[Illustration: FIG. 57_a_.--Indicates the general condition of the
furnace fire during very cold weather. The fuel should fill the
fire-pot to _C_. The ashes should not be allowed to accumulate beyond
_B_, on the grate. There should be no more ashes than appear at _H_, in
the ashpit.]
6. In severe weather give the heater the most careful attention the
last thing at night.
7. Do not overshake or poke the fire in mild weather; once in a while
shake enough to give place for a little more fuel.
8. Do not let ashes bank up under the grate in ash-pit. Grate bars are
very hardy, but it is possible to warp them with carelessness. Taking
up the ashes once a day is the best rule, even if but little has fallen
into the pit.
9. Keep the boiler surfaces and flues clean; a crust of soot 1/4 inch
in thickness causes the boiler to require half as much more fuel than
when the surfaces are clean.
10. If convenient, have a water hose to spray the ashes when cleaning
out the pit.
11. Attend the boiler from two to four times per day. In mild weather,
running with a checked fire, morning and night is usually often enough.
In severe weather, once in early morning, again at mid-day, again at
five or six o’clock and finally thorough attention at from nine to
eleven o’clock in the evening.
12. If, through burning poor coal, the fire pot gets full of ashes,
or slate and clinkers massed together, the quickest way to get a good
active fire is to dump the grate and then build a new fire--from the
kindling up.
13. If a _hard clinker_ lodges between the grate bars, do not force the
shaking, but first dislodge the mass with a poker or slicing bar. Then
the grate will operate without damage.
=Weather and Time of Day.=--In _severe weather_ keep the fire pot full
of coal, and run the heater by the dampers or regulator (if one is
used). Thoroughly clean the grate twice a day. Let the top of the fire
in front be level with the feed door sill. Bank up the coal higher to
the rear.
In _moderate weather_ there should be from 2 to 6 inches of ashes
between the live coal and the grate. As the weather grows colder keep
the grate and the fire pot a little cleaner--sometimes it helps to run
the poker or slicing bar over it through the clinker door. With some
fuels this is never necessary.
=Night Firing.=--In very _cold weather_, when the house should be kept
warm all night, clean the grate well at a late hour--the last thing.
Clear the bottom of the fire pot of all ashes and clinkers so that the
grate is covered with clear-burning, red-hot coals, then fill the pot
full of fuel. If possible, leave some of the flame exposed to burn the
gases. Leave the drafts on long enough to burn off some of the gas,
then check the heater for the night. Thus there is plenty of coal
to burn during the night and some on which to commence early in the
morning. Some drafts do not make it necessary to leave the dampers on
to burn off the gas after feeding.
With the ash-pit draft damper closed and the cold-air check damper
open at night, but part of the coal is burned and there is much of it
not burned in the morning. So, by reversing the dampers in the early
morning the fire starts up quickly and often the house may be well
warmed before any coal is put into the fire pot.
Some boilers are run the other way--a very poor way. If the grate is
cleared off in very cold weather and coal added at five or six o’clock
in the afternoon, by eleven o’clock at night nearly one-half of the
coal is burned and the grate is covered over with a mass of ashes and
clinkers. With little coal remaining, to shake the grate will quite
likely put out the remaining fire; to put fresh coal on a low fire
reduces further its declining temperature. The result is a cold house
that will grow colder until a new fire is started.
Often in cold weather with this poor way of night firing, it takes one
or more hours of forced firing to warm the house in the morning, and
all the coal saved the night before is more than used to get the house
or building “heated up”--while the people who should be comfortable
have to get up, bathe and take breakfast in chilly rooms. At no time
in the day is heat more wanted than about the time of getting up and
starting the day. A fire well cared for late in the evening makes a
warm house all night. And so it follows that it is much easier to add
a little more heat in the morning. And surely less coal is burned, for
the forcing of a fire part of the time often overheats, and wastes coal.
=First-day Firing.=--In the morning of _moderate winter weather_,
with the ash-pit draft damper open, before adding any coal allow the
fire to brighten up if it seems to be low; then (for such conditions)
spread over a thin layer of fresh coal and set the drafts for a brisk
fire. After the new fire is well started add as much coal as may be
necessary to last until next firing. Do not shake much if any--just
enough to give space for more coal. Then by setting the regulator (if
one is used), or, by closing the ash-pit draft damper and opening the
cold-air check damper a little, the boiler should keep up its work
until the next firing time.
In _severe weather_, if the boiler has been attended to at night as
directed in the section on “night firing,” the drafts can be turned on
and the boiler run for half an hour before adding coal. Or, if more
convenient to give it immediate attention, the grate can be thoroughly
shaken and enough coal added to last until mid-day. Often the cold-air
check damper will need to be entirely closed and the ash-pit draft
damper partly open if the heater is a water boiler. If a steam boiler,
the regulator should then be set to maintain the number of pounds of
pressure wanted and so left.
=Other-day Firing.=--In _severe weather_ more coal should be added
about noon, sometimes the draft may be left on for a few minutes and
then checked. And in such weather it is often well to give the boiler
further attention at five or six o’clock. In severest weather the
boiler should not be attended more than four times a day; and generally
not less than three times.
Often much coal is wasted by “nagging” the fire--poking, shaking and
feeding it until it becomes “dyspeptic.” A sure cure is a little common
sense in regular feeding, etc.
=Economy and Fuels.=--In running many boilers for _moderate weather_
better results follow if the grate is not shaken too much or too often.
Sometimes in _moderate_ weather a body of ashes on the grate checks the
fire and there is enough heat without a useless burning of fuel. Many
houses are overheated in _moderate_ weather and too much coal burned by
running the boiler as for zero weather.
So we repeat--_it is not wise to overshake or overfeed a boiler in
moderate weather_. The fire should be in such shape that if a change
comes at night there is a basis for a good fire to start on. When
the grate is shaken but once during the 24 hours (during _moderate_
weather) late at night is the best time.
When one stops to think that heating is needed during about 7 months
out of the year, and that _a greater portion of this time is usually
moderate weather_ when a very little heat is needed, it must be seen
that the science of running the heater to save coal is to apply common
sense rules of limiting the feeding and the attention in such periods.
In _severe weather_ we believe in giving the boiler a liberal quantity
of fuel regularly and at the right time. The time to save coal is when
there is no need for burning it. This is where a great many people make
errors in running the boiler--in forgetting to “let up” on the shaking
and feeding in moderate weather.
With some drafts and for boilers using hard coal or coke, good
economical results often are secured by opening the feed door a little
when it is desired to check the fire in moderate weather. This depends
on the draft.
=For Burning Soft Coal.=--Some types of boilers are made to burn
soft coal with economy, with least work. Some types are made
specially to burn the meaner grades of soft coal. Firing to prevent
smoke is a source of economy and these ways of running should be
followed--specially with large sectional boilers.
There are two types of soft coal, viz.: The free-burning coal, which
breaks apart when burning, allowing the gases to freely escape; and
the fusing-coking coal, which, when burning, first fuses into a solid
burning mass with a hard crust over the top, slowly coking as it burns.
The latter kind is most valuable for house-heating boilers because the
gases are more thoroughly consumed. The fusing-coking coal is worth
about 20 per cent. more for this purpose than the free-burning coal.
The gases should be allowed to pass off from the coal _slowly_. Leave
air inlet on the feed door open if draft permits. If possible, use
uniform sizes of coal. Avoid using coal having too much dust--the
“run-of-the-mine” may be lower in price but its heat-making value is
also low.
For the purpose of slow burning of soft coal, it is well in feeding at
night to let the fire burn up freely so that the coals are very live
with heat. Then fill in enough coal to last all night--leaving some of
the live coals uncovered if possible. With large sectional boilers this
exposure should be at the rear of the fire so that the flame will pass
over the live coals. Thus the gases coming off from the fresh coal are
burned and a larger amount of the full heat-producing value of soft
coal is made use of and with less smoke.
After a boiler is so fed, the dampers (unless an automatic regulator is
used) should be left about as follows:
Ash-pit draft damper open a little or closed, as draft may require.
Cold-air check damper open about one-eighth to one-third distance of
the opening.
Smoke-pipe damper about one-half closed.
A little experiment with the draft will usually tell the operator the
best way of leaving these dampers.
It will be found in the morning that the entire charge of coal is well
burned or partly coked.
The coked fuel, or that which sticks together in a mass, should be
broken up by the poker and more added generally as by rules given in
other sections.
It must always be remembered that the soft coals mined in different
parts of the country have widely varying heat-making capacities. To
obtain satisfactory results brands must be selected which have an
established reputation for excelling results in small boilers.
=For Burning Coke.=--It is best to keep the pot _full_ of fuel--keeping
a large body of coke under a low fire rather than a little fuel under a
strong fire.
It must be remembered that coke makes a very “hot fire” because the
coke is free-burning. Care should be taken not to leave drafts on too
long in boilers not having regulators.
Coke burns best for house-heating purposes with less draft than is
required for coal, therefore to keep a low fire the ash-pit draft
damper should be kept closed, and the smoke-pipe damper almost entirely
closed. The regulator (when used) can be set to keep the dampers about
as here advised. Coke is practically smokeless and its quick-burning
character makes a cut-off damper in the smoke pipe (which will stay
fixed as it may be set) quite necessary.
It is well to keep a layer of ashes on the grates and when shaking stop
before red-hot coals come through the grate. The coke then burns more
slowly, which increases its effectiveness.
With some drafts it may be well to “bank the fire” at night with
coke--pea coal size. This is a matter of experiment, and depends on the
character of the chimney draft.
Fire should be tended regularly--two times a day, or four at the
outside.
With an extra strong draft, at night the fuel should be packed down by
tamping with the back of a shovel.
With ordinary condition of draft, crushed coke, small egg size, should
be used.
=Other Rules for Water Boilers=--_To Fill System._--Open the feed-cock
when the heater is connected with a city or town water supply; if not,
fill by funnel at the expansion tank. Fill until the gage-glass on the
expansion tank shows about half full of water. In filling the system
see that all air cocks on the radiators are closed. Then beginning with
the lower floor, open the air cocks on each radiator, one at a time,
until each radiator is filled; then close the air cock and take the
next radiators on upper floors until all are filled, after which let
the water run until it shows in the gage-glass of the water tank. After
the water is heated and in circulation, vent the radiators by opening
the air valves as before. Then again allow the water to run into
the system until it rises to the proper level in the expansion tank
gage-glass.
Always keep the apparatus _full of water_ unless the building be
vacated during the winter months, when the water should be drawn off to
prevent freezing. _Never draw water off with fire in the heater._
To draw off water, open the draw-off cock at the lowest point in the
system, and then open air cocks on all radiators as fast as the water
lowers beginning with the highest radiator.
=Air-vent Valves on Radiators.=--In order to secure the full benefit of
the heating surface of a hot-water radiator, the inside of the section
must be free of air. When a radiator is “air-bound” it means that parts
of the sections are filled with air in pockets which remain until the
air is allowed to pass off through the vent valve.
Air will gather from time to time at the highest points inside the
radiators, especially in those placed in the upper stories of the
building. These air accumulations inside cut down the working power of
a radiator exactly in proportion as they rob the inside of the casting
of proper contact with heated water. Air pockets not only reduce
effective heating surface, but they also prevent the circulation of hot
water.
Therefore, it is well once in a while to take the little key provided
by the heating contractor and open the air valves on radiators to allow
the air (if any) to escape. When a radiator does not work as well as
usual, open the air valves until the water flows, which indicates that
the air has been fully released. Then close the valve.
=Valves on Cellar Mains.=--If cut-off valves have been placed on the
main and return pipes in the cellar, see that the valves on one line
of main and return pipes (at least) are open when the boiler is under
operation. Be sure that the system is open to circulate water through
the supply and return pipes before building a fire in the boiler.
=End of the Season.=--At the close of the heating season clean all
the fire and flue surfaces of the boiler. Let the water remain in the
system during the summer months. No bad results will follow if the
system is not refilled more often than once in 2 or 3 years. But,
generally, it is thought that best results are secured by emptying the
system once a year (after fire is out) and refilling with fresh water.
It is a very good idea to take down the smoke pipe in the spring,
thoroughly clean and put it back in place. Leave all doors open on the
boiler in the summer time.
=Other Rules for Steam Boilers=--_To Fill Boiler._--Open the feed-cock
when the heater is connected with city or town water supply; if not,
fill through the funnel. Let the water run until the gage-glass shows
about half full of water.
In the first filling, after the water has boiled, get up a pressure
of at least 10 pounds, draw the fire and blow off the boiler under
pressure through draw-off cock to remove oil and sediment, after which
refill with fresh water to the water line. This is best done usually by
the steam-fitter.
The damper regulator will control the pressure of steam, closing the
damper when the pressure is raised beyond the desired point and opening
the damper when the pressure falls below that point. By removing the
weight on the lever, different degrees of pressure can be kept up. The
regulator should be allowed to control the drafts without interference.
Examine the water glass often to see that the _water line_ is at the
proper height. If lower than normal open the supply pipe until the
water runs in and stands at the proper level. It is best when no water
stands in the glass, nor shows at the bottom of the try-cock, to
quickly dump the grate and do not put water into the boiler again until
it is cooled off.
If there is one or more shut-off valves on the main or return pipes,
before starting a fire see that one line of piping at least (main and
return) is open to circulate the steam.
=To Control Radiators.=--When it is desired to shut off steam from any
radiator (if the regular radiator valves are used), close the valve
_tight_, and when it is turned on see that the valve is _wide open_.
A valve partly turned off will cause the radiator to fill with water.
This rule applies only to one-pipe heating systems.
=The Air Valves.=--If little keyed air valves (sometimes called
“pet-cocks”) are used, follow generally the same directions as outlined
for hot-water radiators on page 49--only, of course, in releasing the
air from the radiator open the valve with the key provided and close it
just as soon as the steam unmixed with air comes through the nose of
the valve.
If “automatic” air valves are used they must be carefully adjusted by
the steam-fitter and then left to operate without undue interference.
=End of the Season.=--At the close of the heating season fill the steam
boiler with water to the safety valve and let it thus stand through the
summer.
Also thoroughly clean all the fire and flue surfaces of the boiler and
at the opening of the next season withdraw the water and refill with
fresh water to the water line, starting the boiler as before.
It is advisable to have a competent steam-fitter blow off the boiler
under pressure and thus give the inside a thorough cleaning when the
boiler is first set up and ready for fire.
A low-pressure boiler, using good water, rarely needs blowing off after
it is once cleaned at time of setting up.
THE RIGHT CHIMNEY FLUE
The area of the flue should never be less than 8 inches in diameter
if round, or 8 by 8 inches if square--unless for a very small heating
boiler or tank heater. Nine or 10 inches round, or 8 by 12 rectangular
is a good average size. The flue should generally have a little more
area than that of the connecting smoke pipes.
Draft force depends very much on the height of the flue.
The chimney top should run above the highest part of the roof and
should be so located with reference to any higher buildings nearby that
the prevailing wind currents will not form eddies which will force the
air downward in the shaft. Often a shifting cowl which will always turn
the outlet away from the source of adverse currents will promote better
draft.
The flue should run as nearly straight up from the base to the top
outlet as possible. It should have no other openings into it but the
boiler smoke pipe. Sharp bends and offsets in the flue will often
reduce the area and choke the draft. The flue must be free of any
feature which prevents a free area for the passage of smoke. The outlet
must not be capped with any device which makes the area of the outlet
less than the area of the flue.
The best form of flue is a round tile--in such there is less friction
than in the square form and the spiral ascent of the draft moves in the
easiest and most natural manner.
If the flue is made of brick only, the stack should be at least two
4-inch courses in thickness.
If there is a soot pocket in the flue below the smoke-pipe opening, the
clean-out door should always be closed. If this soot pocket has other
openings in it--from fireplaces or other connections--such arrangements
are very liable to check the draft and prevent best action in the
boiler.
The smoke pipe should not extend into the flue beyond the inside
surface of the flue, otherwise the end of the pipe cuts down the area
of the flue and injures its drawing capacity.
The inside of a flue should be smooth (pointed or plastered). When
the courses are laid with the mortar bulging out from the joints the
friction within the flue is very much increased. Often a troublesome
flue is corrected by lowering some sharp-edged weight by a rope which
should be worked against the sides of the flue until the clogging is
scraped off.
A new chimney when “green” will not have a good drawing capacity. Short
use dries out the mortar and better results follow.
=“Smokey” Chimneys.=--The failure of draft in flues may be due to a
variety of causes, one of which is illustrated in Fig. 57_b_. The short
chimney on the left side of the roof shows the course of the wind
as it passes over the ridge of the roof and why the draft in such a
chimney is retarded whenever this condition exists. The force of the
wind, as it comes into contact with the roof, causes a compression of
the air on the windward side and a rarification on the lee side. This
inequality of pressure causes a downward sweep of the wind as indicated
by the arrows. The effect on the low chimney is to retard the draft and
sometimes the pressure is great enough to reverse the action of the
flue and force the smoke into the house. The only remedy for such a
condition is an extension of the chimney that will raise its top above
the ridge.
[Illustration: FIG. 57_b_.--Effect of the wind in causing down draft in
low chimneys.]
The same effect is often produced by a neighboring building or a border
of trees that are higher than the chimney and dense enough to effect
the wind pressure.