How to have a boiler replaced (without getting steamed)
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Published
August 11, 2009
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I
felt her frustration, but I have to admit, my first thought wasn't about what
she should do. I was thinking about
what she should have done. You see, the way I figure it, the best time
to discuss heating problems is when you're contracting the job, not after the
job is finished.
There's
an easy way to avoid the most common heating problems. All it takes is a good checklist, some
negotiating skills, and the willingness to shop for the best value rather than the lowest price.
Here's
some advice I'd give my best friend if she were shopping for a boiler.
Let's say you have a steam system . . .
If
your steam boiler leaks, or if you realize the old unit has the efficiency of a
campfire, you're probably going to find yourself interviewing heating
contractors. Only the bravest
do-it-yourselfer will tackle an old steam system. As you negotiate with your
contractor make sure you do these things:
* Walk them through your home and discuss your
comfort concerns. If it's too hot in
this room and too cold in that, let the contractor know. If there are gurgling or banging noises in
the pipes or radiators, mention them, and ask the contractor to suggest a
remedy.
Don't
expect a new boiler to magically solve your system-related problems. Explain to the contractor that you're buying comfort, not just a new boiler, and that
you expect the entire system - boiler, pipes and radiators - to work properly
when the job is done.
At
this point, a good heating contractor will most likely explain your
options. Don't be surprised if those
options add to the cost of the job. Many
steam systems suffer from ailments that have nothing to do with the
boiler. When the contractor suggests
these changes, ask if he will guarantee results. A good heating contractor will. If he's not willing to stand behind his work,
there's a good chance he doesn't know what he's doing. Call someone else.
* Don't let the contractor base the size of
your new boiler on the size of your old boiler.
He must measure your radiators
and analyze their ability to condense steam.
If he bases the size of your new boiler solely on the size of your present
boiler, he's discounting the possibility that something may have changed during
the past 60 or 70 years. He's also
acknowledging that the original installer was infallible. (Chances are, that guy wasn't!)
If
the contractor says, "Well, the old one worked well for years so let's use
the same size," know that this guy is not someone who pays attention to
details. Show him to the door.
* Also, don't let the contractor base the size
of your new boiler on a heat-loss calculation of your home. Believe it or not, heat loss calculations
mean absolutely nothing when it comes time to replace an old steam boiler. These calculations mean a lot when you're
sizing the steam radiators, but
you're not replacing the radiators, are you?
Consider
this. Steam is a gas that will eagerly
condense on cold metal. The boiler must
be able to make enough steam to reach the furthest radiator before all the
steam turns to water. In other words,
the boiler's ability to produce steam
must match the system's ability to condense
steam. If the boiler is too small, parts
of your home will always be cold. You'll
burn lots of fuel. If the boiler is too large, the burner will
short-cycle, run inefficiently and the burner parts and controls will wear out
long before their time.
If the contractor doesn't take the time to
survey and carefully measure your pipes and radiation, he doesn't understand
steam heating. Tell him to have a nice
day, and then throw him out.
* The piping around a modern steam boiler is
crucial to the production of "dry" steam (steam that contains no more
than 2% water). If the steam is wet, it
will condense before it reaches all of your radiators. You'll wind up with high fuel bills and
uncomfortable rooms.
Nowadays,
most reputable steam boiler manufacturers consider the piping immediately
around the boiler to be a part of the boiler.
They publish installation booklets showing the contractors how they must
install their boilers. If a contractor
doesn't follow the manufacturer's instructions, the boiler won't operate
efficiently, and there's a good chance the manufacturer won't honor their
warranty should you have a problem.
So,
insist on seeing the installation-and-operating manual beforehand. Have the contractor show you the correct
near-boiler piping for the unit. And
have him include in his contract a clause saying that he will install the
boiler in full accordance with those instructions. This alone will scare away heating
contractors who don't know what they're doing when it comes to old steam
systems. Good riddance to those guys!
* Don't accept copper tubing for the boiler's
supply piping. Copper expands and
contracts much more than steel. Because
steam piping can take some odd angles, the expansion of the copper often puts a
lot of torque on the soldered joints.
That twisting action frequently causes the joints to come undone after a
few years. And then you're on your own.
Proper
steam piping calls for threaded steel pipe and fittings. The threads allow the steel pipe to twist
without coming apart. Copper tubing is
the province of the low bidder. If
you're planning to stay a while in your old house, insist on properly
installed, threaded steel pipe.
* Modern high-efficiency boilers sometimes
don't get along well with old chimneys. Make
sure you ask every heating contractor who steps into your home about your
chimney. This is for your safety and
protection.
An
old chimney may need to be lined with stainless steel to keep the flue gases
from condensing inside the chimney.
Condensing gases form an acid that can eat through the mortar and cause
parts of your chimney to fall apart.
This, of course, leads to poor venting and potentially dangerous levels
of carbon monoxide in your home. Carbon
monoxide is deadly. If the contractor won't
talk about your chimney - if all he cares about is the boiler sale - he is not
a professional. Go no further with this
person.
* Steam pipes must be insulated to keep the
steam from condensing before it reaches the radiators. In the old days, we used asbestos. Nowadays, we spend a lot of money removing
the asbestos, and we rarely replace it.
Most folks figure the heat isn't "lost" because it's still
inside the house. But if the steam is
condensing in your basement pipes, it won't be condensing in your bedroom
radiators on the second floor. You'll be
burning lots of fuel and you'll be miserably cold.
If
your steam supply pipes are uninsulated, have the contractor include a price
for new insulation. Or insulate them
yourself. You can work wonders with a
few rolls of fiberglass insulation and some duct tape. It may not look pretty, but it works well.
* Reputable boiler manufacturers include
cleaning instructions in their installation-and-operating manuals. The contractor must follow these instructions
if your new boiler is to make dry steam.
Have the contractor show you these instructions, and have him write on
the contract that he will follow them to the letter. Then make sure he does.
It
takes nearly a full day to properly clean an old steam system. There is no chemical or magic potion I know
of that can make decades worth of dirt vanish.
Don't accept shortcuts.
* Have the contractor install a drain valve in
the boiler's mud leg. The mud leg is the
drum at the very bottom of the boiler, the place where sediment will
gather. If you don't insist on this
drain valve, you probably won't get it.
Most contractors will leave the drain valve out to save a few bucks, but
without it, you won't have a way to flush sediment from your boiler as the
years go by. Dirty boilers have shorter
life spans than clean boilers.
* Get the contractor to inspect your air vents
and replace them if necessary. You'll
find these air vents on your radiators (if you have a one-pipe steam system)
and near the ends of your mains (on both one- and two-pipe steam system). Good air vents make a dramatic difference in
system performance. Even a brand-new
boiler will gobble fuel if the air vents are old and clogged.
Be
prepared to pay extra for the vents. But
take some comfort in knowing that this
is one of the best investments you can
make in your old steam system.
* Heating contractors buy their equipment from
plumbing and heating wholesalers who handle specific brands of boilers. Since the wholesaler extends credit to the
contractor, the contractor will usually buy what the wholesaler stocks.
Because
of this, you may find it difficult to get three or four competitive prices if
you base the comparison on a particular boiler.
You see, the contractors you speak to may buy from different
wholesalers. If you ask for Brand A and
the contractors' wholesalers stock Brands B or C or D, each contractor will try
to sway you to the brand he's used to installing.
Rather
than try to level the playing field by having them all quote on a certain
boiler, do this: Let each contractor
quote on what he thinks will best heat your home, but have each contractor
guarantee the results in writing. Have
them say, for instance, that when they're finished, your house will heat comfortably,
evenly and with no noise or squirting air vents. Some contractors will run for the hills when
they realize you're buying results instead of just a boiler, but you're better
off without those guys anyway.
A
good contractor will talk to you seriously about your system's problems and
their solution. He'll most likely
suggest things that go beyond a simple boiler replacement. There are people out there who have no
problem guaranteeing results.
A
final note on steam heating. Competent
steam contractors generally charge more for a boiler replacement than others,
but these guys deliver those wonderful results - increased comfort and
substantial fuel savings. They'll never
be the low-bidder, but they're well worth their price.
And
please remember that to be proficient at steam heating, a contractor doesn't
have to be 70 or 80 years old. He just
has to be someone who's done his homework well, and who knows how to listen
well to your concerns about comfort in your old house.
Changing that hot water boiler?
Hot
water heating systems aren't as touchy as steam systems, but when it comes time
to replace the boiler, there are still plenty of things you need to watch out
for. Here are a few:
* Insist that the contractor do an accurate
heat loss calculation of your home. Hot
water heating is very different from steam heating. With steam, the boiler's ability to produce
steam has to match the system's ability to condense steam. In a hot water heating system, the heat
travels on the water like a passenger on a train. It gets on in the boiler and off in the
radiators. The water doesn't condense
along the way as it does in a steam system.
It stays liquid throughout the trip.
Because
of this, the only correct way to size
a new hot water boiler is by measuring how much heat your old house will lose
on the coldest day of the year. We call
this a heat loss calculation.
Now,
you're going to learn that many contractors are in a hurry. They'll use "rules of thumb" to
size your new boiler. These methods are
usually very conservative. They're
designed that way so they won't cause a problem for the contractor.
The
trouble is, you might wind up with a boiler that can heat your home with the
windows and doors wide open. And then
you'll have to feed it.
Other
contractors size boilers by the "Label Method." They look at the existing boiler and say,
"Hey, it's worked fine for years!"
Then they give you the same thing.
This makes no sense because whoever sized the old boiler did it long before decent
windows and effective insulation came along.
Every structural improvement you've made to your old house affects its
heat loss. Don't buy more boiler than you need.
Insist on accuracy.
To
do an accurate heat loss calculation the contractor must measure all the walls,
windows and doors. It takes an hour or
more to size the typical house by the book.
Nowadays, many progressive heating contractors use computerized heat
loss software that makes the job a snap.
But whether it's done longhand or by computer, ask the contractor to
include a copy of his heat-loss calculation with the contract.
* And as with steam, discuss comfort related
issues with the contractor before you
give him the job. Here again, let him
know if some rooms are too hot while others are too cold. If possible, base the contract on final
system performance, rather than on the boiler replacement alone. And be prepared to invest more than the cost
of the boiler, if necessary. Remember,
you're not buying a boiler. You're
buying comfort.
* Be aware that you don't necessarily have to
insulate hot water pipes, unless, of course, they run through areas where the
circulating water might freeze. Hot
water heating is very different from steam heating. With steam, we're dealing with a gas that
desperately wants to become a liquid. In
a hot water heating system, we start with a liquid and end up with a
liquid. Remember, the heat rides the
flow like a passenger on a train. If
some heat gets off in the basement, you'll still have heat moving to that far radiator
up in your bedroom because hot water can't condense into anything other than
what it already is.
* If the contractor suggests you fill the pipes
with antifreeze instead of water, make sure the antifreeze he uses is the type
specifically designed for hot water heating systems. Automobile antifreeze is not suitable for a
hot water heating system because it can't take the extreme temperatures you'll
find inside a boiler.
And
if you go with antifreeze, know that you'll have to check it from year to year
and change it periodically. If you
ignore antifreeze it will become corrosive and eat away at the metal parts of
your system.
* If you have an old gravity hot water system
and the contractor is installing a new boiler with a circulating pump, make
sure he uses a flow-bypass line around your new boiler. This is very important because without the
bypass, the water entering the boiler will be too cool. Cold water can crack hot metal. It can also cause the flue gases to condense
inside the boiler and munch on the metal.
Reputable heating contractors are very aware of this potential problem.
The
boiler manufacturer specifies the piping arrangement for the bypass. Ask the contractor to show you the
manufacturer's drawing in the installation-and- operating manual before you
give him the job.
Discuss
heat balance with the contractor as well.
Old gravity hot water heating systems often do strange things when a
contractor adds a circulator. Remember,
you're interested in comfort more than you are in the components of the
system. Base your contract on system
performance and you'll be fine.
* Insist on a good air separator. Every hot water heating system needs one of
these important components because when you heat water, air comes out of
solution. Without an air separator, the
air winds up in your radiators, and you wind up bleeding those radiators every
few weeks during the winter. Save
yourself a lot of time and aggravation by asking for an air separator.
* Although they're not required by law in most
states, I think every residential hot-water boiler should have a low-water
cutoff switch. All states call for this
important safety device on steam boilers, but they haven't yet gotten around to
mandating them for small hot water boilers (they are required on multi-family
housing and commercial buildings).
Should
the water leave the boiler, for whatever reason, a low-water cutoff will shut
off the burner. An automatic water feed
valve, which is a common component on residential hot water boilers, offers
little or no protection against a low-water condition, and can actually add to
the problem should the boiler or a pipe spring a leak.
If
you're changing your boiler, ask your contractor about low-water cutoffs. The protection they offer is well worth the
small additional cost.
* Have the contractor clean and flush your
entire system after he installs the new boiler.
Like steam systems, hot water systems work much better when they're
clean. Smart contractors know this and
they'll flush a new system as a matter of course. Ask about cleaning before you sign on the
dotted line.
I've
found that heating contractors pay the greatest attention to, and take the
greatest care with, knowledgeable
consumers. If you show an interest,
they'll take the time to explain the latest technology and they'll tell you
about the newest products.
I
know of no heating contractor who is looking for trouble. The seeds of most problems get planted with
bad communication. So take the time to
discuss your comfort concerns with
your contractor. Ask if the new product
you're planning to buy - be it a boiler, a new radiator or whatever - will
solve your comfort-related problems. If
he assures you it will, he should have no problem basing his contract on the
results.
A Glossary of Common Heating System Components
Air Separator: We use these on hot water heating systems to
scrub air bubbles out of flowing water.
There are several types available and the more expensive ones work
better than the cheaper ones. The air
separator belongs on the main supply pipe where the water is hottest.
Aquastat: This electrical control is a component on
every hot water boiler. Its job is to
limit the water temperature to a preset high point. Some aquastats also keep the circulating pump
from starting until the boiler reaches a minimum temperature.
Automatic water feeder (for steam systems): This optional
device, which is widely used on steam boilers, will maintain a safe, minimum
water line in the boiler. It's a back-up
safety device for the low-water cutoff.
Don't think of an automatic water feeder as a convenience item. You still need to check you boiler's water
line regularly.
Backflow preventer: Used on hot water boilers, backflow
preventers keep boiler water from flowing backwards into the public water
supply should a water main break. In
many states, backflow preventers are required by law.
Boiler: This is the vessel that holds the water. Steam boilers and hot water boilers are very
similar in appearance. The main
difference lies in the water content and the controls.
Burner: The burner is the device that makes the fire
inside the boiler. Burners run on
natural gas, propane and fuel oil. They
need to be cleaned periodically and tuned using specialized instruments.
Circulator: Like the motor on a Ferris wheel, the
circulator in a hot water heating system turns the water around and
around. The heat moves on this flow like
a passenger on a train. It gets on in
the boiler and off in your radiators.
Compression Tank: When you heat water it will expand. Since a hot water heating system is closed to
the atmosphere, we have to give that expanding water a place to go. That's the job of the compression tank. You'll almost always find the tank hanging
around near the boiler, but if you have an old gravity hot water system, look
in the attic. When tanks are in the
attic (with an overflow pipe that runs out onto the roof), we call them
"expansion" tanks. But by any
name, the tank does the same thing.
Feed valve: This is the valve that puts the water in your
hot water heating system. Sometimes
called a pressure-reducing valve or, simply, a PRV, this valve's job is to lift
water to the highest point in the system and to place that
Low-water cutoff: Low-water cutoffs have one job to do. Should the boiler lose water, for whatever
reason, this device will shut off the power to the burner before the situation can
become dangerous.
Tridicator gauge: You'll find this gauge on your hot water
boiler. It shows you three things: the water temperature, the boiler pressure,
and the height of the water in the system.
A service contractor will use the tridicator gauge while troubleshooting
your system.
Relay: A relay is a sort of electrical traffic cop
for a hot water heating system. It
relays signals between the room thermostat, the circulator, the aquastat and
the burner, and gets all these important components working together.




