Renewable Energy Design

What is an efficiency rating?

An efficiency rating is a unit of measure developed by the U.S. Department of Energy to rate the energy efficiency of a piece of equipment. The higher the efficiency rating, the more efficient the equipment is.

If you have a boiler, do you need a separate hot water heater?

No, the hot water is heated directly by the coil in the boiler.

What is an expansion tank used for? Where is it located?

An expansion tank is used on a boiler, as the water heats up it expands and needs a place to go. Usually the expansion tank is located above the boiler and holds more than 2 gallons of water.

Why would an expansion tank need to be drained? How is this done?

If all the setting are correct on a boiler the expansion tank should never need to be drained. The tank constantly has water in it so ever if you drain it water will flow back into the tank. To drain the tank, you need to open the relief valve at the bottom of the tank, hook up a tube and drain.

What is the difference between a hot water and steam boiler?

A hot water boiler has an expansion tank and a steam boiler has a sight glass.

Why do you need to purge the system? What is involved?

You would need to purge a system because air is in the lines and water is not flowing to the radiators. By using a key from a hardware store, open the valve on the radiator until you get a steady stream of water. You will need to start at the first floor radiators and work your way up.

Boiler systems have a pressure/temperature settings that are visible on the boiler, what are the proper settings? What temperature/pressure is dangerous and should the CSR advise the customer to shut off the unit?

A steam boiler's pressure gauge should read about 4-5lbs and a hot water boiler's gauge should read about 12-15lbs. The temperature should be less than 200 degrees and if it reaches 250 degrees the unit should be shut down.

Can a crack in a boiler be patched, or does the entire unit need to be replaced?

If a boiler has a crack, it cannot be patched, and it will need to be replaced.

Where is the emergency switch located? When should this be used?

The emergency switch is usually located at the basement's exit, at the top of the steps or near a back door. This switch is identical to a light switch, but it usually has a red switch plate. It should only be used when you need to cut the electricity to the furnace or boiler in case of a problem.

Where is the reset button located? Why should you only press it one time?

The reset button is always red and is usually located on or near the burner. On systems that are 40 years old or older, the reset button is located on the smoke pipe. When the reset button is pressed it causes fuel to flow into the system. It is a bad idea to press the reset multiple times, because it can cause the system to flood.

What is a prime and start? Is this procedure different for a furnace than a boiler?

A break in the fuel line or an empty fuel tank would make it necessary for a technician to perform a prime and start on a furnace or boiler. To do this, the technician must first trace the oil line to the pump and loosen the bleeder valve. Then he must attach an oil line to the pump, press the reset button on the system, and allow the line to run until there is a steady stream of oil reaching the furnace or boiler. This process is the same for both a furnace and a boiler.