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A: How much heating energy do you get for your
dollar?
- 1 gal of #2 oil contains 140,000 Btu of
energy.
- 1 gal of #6 oil contains 153,000 Btu of
energy.
- 1 therm of gas (or 100 cubic feet of
gas) contains 100,000 Btu of energy.
- [1 Btu (British thermal unit) is the
amount of energy needed to raise the temperature of water one degree
Fahrenheit (1F).]
- 1 watt-hour of electricity = 3.4 Btu
- 1 KWH (kilowatt-hour) is 1,000 watts for
1 hour, the same as 3,400 Btu
Example: When #2 oil costs
$2.00/gal and gas, s $0.87 a therm, what is the cost comparison?
Solution:
1. How much does an energy unit of gas cost? Using your calculator, divide
the cost of a therm of gas by the 100,000 energy units in a therm, as
follows:
.87 divided by 100,000 = 0.0000087. Leave that number in your calculator.
Multiply that number by the energy units in a gallon of oil (140,000).
The answer should be 1.218 ($1.22) Therefore, you would pay $1.22 for the
same heating energy as you would get from a gallon of No. 2 oil.
2. You can go one step further. Divide the cost of the gas by the cost of
the oil: 1.22/2.00 = 0.61, which means that your fuel bill would be 61% of
your oil bill. But keep in mind that the cost of fuel is not stable. The
answers here apply only when oil and gas prices are as assumed above. Use
your own numbers!
B: How to Have an Efficient Oil-Fired Boiler
The Right Nozzle: No oil burner can be tuned properly without the right
nozzle. Few mechanics bother sitting in traffic for an hour or two to buy
the right nozzle. Usually, they install whatever they have on the truck.
To find out what nozzle your oil burner needs, write down the firing rate
from the boiler's nameplate or from some registration papers you find. Do
not go by the numbers on the oil burner because oil burners are manufactured
to run at different firing rates on different boilers. On the boiler's
nameplate, it is called the firing rate, the input rating or the input.
Don't bother with "gross output," "output," "net output," etc. Just "input."
Also, write down the brand name and model of the boiler, if you can find it.
Then, call the company that manufactured your oil burner and ask them what
nozzle should be on your burner for use with your boiler. They will tell
you, for free, and be very helpful. From them, you need to know gallons per
hour, spray angle and spray pattern. Some will also recommend a brand of
nozzle that works best. Also, ask the oil burner manufacturer to mail you a
copy of the adjustment instructions for your oil burner.
You can buy that nozzle from a heating parts supply house or ask the
mechanic to install only that nozzle. They cost $5. for #2 oil, $60. for
either Nos. 4 or 6 oil. (Most burners have only one nozzle.)
Install a Pressure Gauge: Ask your mechanic, also, to install a pressure
gauge on the burner to indicate oil pressure, because adjustment of pressure
is also very important. Ask for the more expensive ($20.) liquid filled
gauge instead of the cheaper gauges that are normally used.
Have your mechanic install the nozzle and gauge and then adjust the oil
burner according to the instructions. Proper adjustment can be made only by
repeated taking of exhaust gas readings with instruments, then repeatedly
making adjustments until the readings are just right. The measurements of
carbon dioxide (CO2) and Smoke Number are used to decide what burner air
adjustments are needed. The Smoke Number should be Zero on all oil burners.
CO2 should be between 10% and 13%.
Install a Thermometer in the Chimney: Have your mechanic to install a
thermometer in the chimney (costs about $40 to buy) if there is none there
now, using a one-half inch floor flange. The flange is available sometimes
for about $2. at some plumbing supply stores. Read the temperature soon
after the boiler has been cleaned and tuned. Mark it with a Magic Marker.
Later, if the temperature has risen by up to 50 degrees Fahrenheit, don't
worry about it. If it goes up 100 deg or more, the boiler is out of tune,
dirty or both. If the temperature does not go up, you can be sure the boiler
is pretty clean and reasonably well tuned compared to when you first
measured and recorded the temperature. All readings of the thermometer
should be taken after the burner has been running a few minutes from a cold
start.
Don't Ask Only "How Much!" Most owners ask only "How much?" and nothing else
about tune-up. Thus, there is tremendous pressure on mechanics to hurry and
cut corners. This causes you to burn more fuel and have many more
breakdowns. A properly installed and tuned burner will average 3+ years
between break-downs. I know because I do this work all the time.
Unfortunately, most burners break down much more frequently.
Good Enough? If you take the time to get the right nozzle, you will save
about half of the time that a tune-up takes to be done right. Mechanics
usually work without instructions for specific burners. Thus, ignition
settings and other things are set at an "average" setting that is less than
optimum for your burner. If your mechanic says that he "tunes it by looking
at the fire" or has a nozzle that is "good enough," he is right, for this is
how it is normally done. But don't stand for it! He'll say that he has been
"doing it this way for 30 years with no trouble," and he will be right
because he has had no trouble. If he disagrees, ask him to call the oil
burner factory and argue with them.
P.S.: Oil burners common around New
York City basements: Beckett (800) 645-2876 and Carlin (800) 989-2275. If
you need to find another company's or the boiler manufacturer's number, try
calling (800) 555-1212 or call the public library's Reference Desk and ask
them to look up the company in a trade name directory.
APPENDIX: Suggested Arrangements for Making Heat and Hot Water for
Different Size Buildings
1,2 or 3-family houses: (Heated with hot water) Install a direct vent,
sealed combustion boiler and a stainless steel indirect water heater.
Install thermostatic radiator valves (TRV’s) on every radiator or convector,
with locks on the tenant radiators. My favorite locking operator (limited at
the high end but tenant adjustable lower) is the Danfoss #013G820. Wire the
boiler for cold start and outdoor reset. Heat-Timer’s HWM-100 is my favorite
control to do this. Protect the boiler from condensation with a
non-adjustable mixing valve such as Danfoss Thermic Valve #065B8923.
Larger than 2 or 3-family: (Heated with Hot water) The dividing line is
where the load is too large for a direct vent, sealed combustion boiler
(about 45 kilowatts = about 153,000 Btu per hr). Use a chimney-vented boiler
and stainless steel indirect domestic hot water heater. Install thermostatic
radiator valves on each radiator. Wire the boiler for outdoor reset, and,
maybe, a minimum temperature. A very low mass boiler may be able to start
from cold to warm up the hot water tank quickly enough, especially if the
tank is oversized a bit; in this case, install a thermic valve to protect
the boiler. If you don’t do cold start or you find out after installation
that the boiler doesn’t warm up quickly enough, just set the "boiler
minimum" in the control for 120 or 140. The thermic valve should still be
installed in this case.
Larger than 8 or 10 families: (Hot water heat) Dividing line is where the
largest stainless steel indirect domestic hot water heater (120 gallons)
can’t carry the load. Use chimney-vented boiler with copper coil in the
boiler and a Tour-Anderson mixing valve to make hot water at 120F. Install
the valve in accordance with the manufacturer’s instructions. Wire the
boiler to stay at 150 or 160F minimum all year, and reset the heating system
water temperature with a mixing valve controlled by an outdoor reset
control. Use the end switch in the mixing valve to run the boiler up to 200F
in the coldest weather. Install thermostatic radiator valves on each
radiator.
In all systems for heating with hot water, the heating water circulation
pump should run non-stop whenever the outdoor temperature is cold enough for
the building to need heat, usually around 55 to 60F. In all the above cases,
there should be a return line on the domestic hot water piping with a Taco
003 or larger pump running non-stop to keep the mixing valve working, if you
have one, or to prevent stratification (and overheating water) in an
indirect water heater. Calculate the friction in the piping to size the
piping and the pump. Size radiators and boiler according to Manual J, which
can be purchased from ACCA at (202) 483-9370.
With steam systems, make hot water in the boiler. Use stainless steel
indirect heater for up to 8 or 10 families Use coil and Tour-Anderson mixing
valve for larger buildings. Size boiler to radiators, not house.
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