Repairman servicing or repairing basement furnace unit

HEATING experts say that homeowners who have not prepared their heating systems for the winter should do so right now. Test runs and precautionary measures, they say, can help avoid surprises when the thermostat sends its first call for heat and the furnace grunts and rumbles in response.

Here, then, are some tips for insuring a successful heating-system startup and avoiding a last-minute emergency call to the service company on the first bitterly cold day of winter.

”The first thing to do is make sure the boiler starts,” said Robert Frezzo of Jules Frezzo Oil Service, a plumbing and heating company in Union City, N.J. While such advice may seem obvious, Mr. Frezzo said, a significant number of service calls on the first really cold day are prompted by heating systems that simply fail to start.

Mr. Frezzo said four kinds of heating systems were generally in use today.

An all-electric system, he said, is made up of a number of electrically powered heating elements, much like long, wall-mounted toasters. Electric heating elements either work or they don’t. Those that don’t should be repaired or replaced by a licensed electrician.

More common than all-electric systems, however, are systems that use either an oil- or gas-fired furnace to generate heat.

With steam-heat systems, he said, the furnace heats water to a boil and distributes the resulting steam through pipes and vertical risers to radiators throughout the house.

Hot water systems, he said, use a pump to move the hot water itself — rather than steam — through pipes, risers and radiators and then back to the furnace. With hot-air systems, Mr. Frezzo said, air is heated instead of water. The heated air is pumped throughout the house via ductwork and then back to the heat source for recirculation.

The way to check whether a furnace is going to start when it is supposed to, he said, is to raise the thermostat setting to a point where the room temperature — whatever it happens to be — is lower than the setting on the thermostat. After a minute or two, Mr. Frezzo said, the furnace should come to life.

But what if it doesn’t?

”Check the switches and the circuit breaker,” he said, explaining that over the summer, the main cutoff switch to the furnace — typically located at the top of the basement stairs — or the switch on the furnace itself might have been turned off. It is also possible, he said, that the circuit breaker may have tripped or a fuse may have blown on the circuit that powers the furnace.

If all the switches and circuits check out, Mr. Frezzo said, homeowners with steam heat should insure that there is water in the boiler by checking the water level in the glass tube attached to steam furnaces. Most such systems, he said, have low-water cutoff switches that automatically shut down the system if the water in the boiler falls below a certain level. The low-water cutoff device should be flushed anyway, Mr. Frezzo said, to remove any sediment that may have accumulated. That can done by opening the valve at the bottom of the cutoff fixture and letting it drain until the water runs clear.

Homeowners with oil-fired furnaces that refuse to start, he said, should insure that the valve from the oil tank to the furnace is open and that there is oil in the tank. Those with gas-fired furnaces, he said, should make sure the gas line to the furnace is open and the furnace’s pilot light is lit.

If, after the above measures are taken, the boiler still doesn’t start, Mr. Frezzo said, a call to a service company is probably necessary. ”The sooner, the better,” he said, explaining that most plumbing and heating contractors will undoubtedly be swamped with calls during the first cold snap.

Once the furnace starts — either on its own or with help from a professional — there are some other things to do. ”Let it run for a while, at least until it makes some heat,” said Tom Berry, the owner of Laurelhurst Oil Company in Seattle.

Mr. Berry, who answers questions about heating systems on his Internet Web site (, said that problems will be revealed only by letting the system go through its paces. Among the easier-to-identify problems, he said, are malfunctioning air-vent valves in steam-heat systems and low water levels in hot-water systems.

Air vents on steam systems, Mr. Berry said, allow cooler air to escape as the steam fills the system. The vent — which should close when the hot steam reaches it — can get stuck either in the open or closed position. If a radiator fails to get hot from one end to the other, Mr. Berry said, it is a good bet the valve is stuck in the closed position and will not allow air in the radiator to escape.

On the other hand, he said, if the radiator gets hot and then continually hisses, it is likely that the valve is stuck in the open position, allowing steam to escape when it shouldn’t. In either case, Mr. Berry said, the faulty valve should be removed and cleaned or, better yet, replaced.

Mr. Berry said that radiator valves come with different-sized vent holes that allow for fine-tuning a heating system. Generally, he said, valves with smaller vents can be installed on radiators closest to the furnace while those with larger openings can be installed at more distant locations.

Proper placement of appropriately-sized valves, Mr. Berry said, can insure that all radiators heat up at the same time, as opposed to those closest to the heat source heating up — and possibly switching off the thermostat — before more distant radiators are fully heated. Vent sizes and instructions for placement, he said, are typically printed on or enclosed within vent packaging.

Hot-water systems, Mr. Berry said, are meant to be completely filled with water. That means that if gurgling sounds are heard, or if some radiators fail to get hot, there may be air in the system. The air can be purged, he said, by opening the bleeder valve at the top of the radiator and allowing all trapped air to escape. The valve should be closed only when water begins to emerge.

Mike Spall, a spokesman for Consolidated Edison of New York, said that homeowners with hot-air heating systems should replace the filters in their systems at the beginning of the heating season and at least once a month thereafter. In addition, he said, all visible ductwork should be inspected to insure that no combustible objects have been placed on or near the ducting. Radiators and radiator covers should be cleaned and any items that have been placed on top of unenclosed radiators should be removed.

All the experts interviewed said that furnace vents and chimney flues should be inspected — preferably by a professional — to insure proper venting of the gases created during combustion of natural gas or oil.

”Carbon monoxide is a colorless, odorless gas that is created by many combustion appliances, particularly furnaces,” said Andrew L. Port, a certified industrial hygienist with Environmental Waste Management Associates, an environmental consulting firm in Parsippany, N.J. ”Basically, carbon monoxide is an asphyxiant that takes the place of the oxygen in your blood. ‘First, it puts you to sleep; then it kills you.”

Mr. Port said that every home that uses any form of combustion for heating should have carbon monoxide detectors installed near the furnace and in various rooms of the house. ”You usually don’t realize you have a carbon monoxide problem until it’s too late,” Mr. Port said. ”Why take chances?”

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