0
if increase the pressure in positive way. the furnace's life degrades rapidly moreover you are getting back pressure / fire from fuel feed door similarly exit the air in gaps between insulation brick it leads to chance of collapse brick wall easily ref this page describes very clearly http://www.brighthub.com/engineering/mechanical/articles/62184.aspx
thanks
t.p.sivanandan from
http://www.share2others.com
Wiki User
∙ 13y ago
Add your answer:
Earn +20 pts
How FD and ID fan control the air flow?
FD or Forced Draft Fans supply combustion air to the boiler. Different combustion controls demand a supply of combustion air in different ways but what they have in common they control the FD fan to provide enough air for complete combustion in the boiler furnace. In most systems in use today the ID or Induced Draft fan sucks the products of combustion from the boiler furnace, through the various passes of the boiler and pushes it out the chimney. How much or how fast this fan works is based on furnace pressure. The ID fan control set point is based on combustion side furnace pressure. If the furnace pressure goes up the ID fan removes more air to lower the pressure. As the furnace pressure goes down the ID fan removes less air. This air flow out of the boiler is referred to as draft. Both the FD and ID can be controlled by various means. The air flow can be restricted in the plenum or ducts by dampers or louvers or the speed of the fan can be changed by mechanical means from a fixed speed driver. Also the speed of the fan can be changed by the use of a variable steam turbine or an electric motor with VFD (Variable Frequency Drive)
Can you use a down draft as an updraft furnace?
yes u can if u are good with duct work put a down draft furnace in a basement and pipe it up one floor well not recommended it will work i did this to help a lady get threw winter who had low funds and it has worked quite well u need to build a custom box for the furnace to sit on to make this work and pipe directly from box and use smallest duct work u can i.e mobile home duct work or 4 to 6 inch What you did is still a downdraft furnace
Is forced draft has negative pressure drop?
No, the forced draft fan has positive pressure as it just forces yhe air into the combustion chamber.only the induced draft fan has negative pressureas it removes the flue gases & exhaust gases is stacked up
How do you detect a crack heat exchanger in a furnace?
The most comon way to detect a crack in a heat exchanger is with a visual inspection, removal of the burner assembly and the use of a mirror and flash light. Or a smoke bomb test. A special little smoke bomb is placed in the burner area with the burners OFF. The blower is runnig and you light the smoke bomb, the smoke will draft up the flue vent or if a crack or rust hole is present then the smoke will get sucked into the air stream and come out of the duct work. Other than that using a carbon monoxide detector to see what the CO levels of the furnace are and comparing them to the supply air of the furnace to verify that there is no CO present in the air stream. The best and most accurate way is to contact a local Heating and Air Conditioning specialist or your local gas company should come out and perform a CO test on the furnace. Good Luck and God BLess
Should the air induction blower continue to run after furnace blower motor starts?
If you are refering to the inducer motor( the one with the little wheel that you see when you take your units doors off) Yes it should keep running when your blower motor is running and before ignition to create your draft and during to rid the gases out your flue Hope I kept it simple
Why induced draft fan operate first instead of a forced draft fan?
The procedure for starting draft plant (fans) in a boiler is to start the ID Fan first. Remember that the purpose of the ID Fan is so that the Furnace operates at a slight vacuum. (See Related Link: FD Fan vs ID Fan.) Any casing or furnace leaks then allow air to leak in, rather than allowing air with pulverised fuel and fly ask to leak out.
What is draft in boiler?
when the weight of warm air in the stack is less than the cool air around the stack , it causes an upward flow pulling air thru the furnace
What is draft in a boiler?
when the weight of warm air in the stack is less than the cool air around the stack , it causes an upward flow pulling air thru the furnace
What is natural draft in a boiler?
when the weight of warm air in the stack is less than the cool air around the stack , it causes an upward flow pulling air thru the furnace
Forced draft fan vs induced draft fan?
In a balanced draft boiler, you actually have both: forced draft (FD) fans supplying air to the furnace, and induced draft (ID) fans removing flue gas. Typically, the FD fans control airflow, while ID Fans control furnace pressure to slightly below atmospheric pressure. In general though, the choice between forced draft and induced draft is based on how "tight" the system is - if you have leaks, it is better to use ID, as FD will cause product loss.
How FD and ID fan control the air flow?
FD or Forced Draft Fans supply combustion air to the boiler. Different combustion controls demand a supply of combustion air in different ways but what they have in common they control the FD fan to provide enough air for complete combustion in the boiler furnace. In most systems in use today the ID or Induced Draft fan sucks the products of combustion from the boiler furnace, through the various passes of the boiler and pushes it out the chimney. How much or how fast this fan works is based on furnace pressure. The ID fan control set point is based on combustion side furnace pressure. If the furnace pressure goes up the ID fan removes more air to lower the pressure. As the furnace pressure goes down the ID fan removes less air. This air flow out of the boiler is referred to as draft. Both the FD and ID can be controlled by various means. The air flow can be restricted in the plenum or ducts by dampers or louvers or the speed of the fan can be changed by mechanical means from a fixed speed driver. Also the speed of the fan can be changed by the use of a variable steam turbine or an electric motor with VFD (Variable Frequency Drive)
What is a balanced draft and how is it controlled?
furnace equipped with FD(force draft) and ID(induced draft) fan /blower are called balanced draft system.Fd used to regulate combustion airflow while ID used to regulate furnace pressures type of furnace operate slightly below ATM pressure .
What is the function of forced draft fan?
force draft fan is helped in producing draft. therefore, no requirement of more chimney height. with the help of forced draft we would rapidly circulated the air from boiler to chimney. this fan is mounted near the boiler bottom.
What removes the combustion gases from a balanced draft furnace?
A balanced draft has both ID and FD fans. ID Fan works by pulling the gases through the furnace hence creating the required draft. Where as FD fan pushes the gases into the furnace. Hence in a balanced draft frunace, the ID fan can said to be removing the combustion gases.
What is furnace draft control?
A valve that brings atmospheric air into the furnace exhaust to help expel the exhaust gases.
What is Difference between natural draft and forced draft in modern furnace technology?
natural draft depends on:ambient air conditionsconditions of the leaving gaschimney height
What is the purpose of the draft diverted on a gas furnace?
It protects the Pilot Light from being blown out
