HVAC shee v9

V-Belt

• Most commonly used belt • Cheap and have large range in horsepower and speeds • Come in many different material types and sizes Drive belts are also called V-belts because of the way their rubber teeth are tapered.

nitrogen oxides

(NOx) Major source is auto exhaust. Primary and secondary effects include acidification of lakes, respiratory irritation, leads to smog and ozone. Reduced using catalytic converters. Oxides of nitrogen are a mixture of gases that are composed of nitrogen and oxygen. Two of the most toxicologically significant compounds are nitric oxide (NO) and nitrogen dioxide (NO2). Other gases belonging to this group are nitrogen monoxide (or nitrous oxide, N2O), and nitrogen pentoxide (NO5).

in (or out of) step

(of two or more oscillations or other cyclic phenomena) having (or not having) the same frequency and always in the same phase.

too much excess air causes

- lower flame temperature - lower combustion gas temperature - higher flue stack gas temperature - poorer heat exchange to the distribution medium not enough excess air is much worse. CO, soot, rot out the equipment, clog flue with soot

Hot water boilers have two aquastats. One acts as an operating control which is just a pressure cut in and cut out. The other is a high limit control

/

bar to psi

1 bar = 1 ATM 1 bar = 14.5 psi

CRAC hvac systems

A computer room air conditioning (CRAC) unit is a device that monitors and maintains the temperature, air distribution and humidity in a network room or data center. CRAC units are replacing air-conditioning units that were used in the past to cool data centers.

stop valve

A device installed in a water supply line, usually near a fixture, that permits an individual to shut off the water supply to one fixture without interrupting service to the rest of the system.

flame retention head

Consists of center opening, primary slots, and secondary opening. Used on oil burners. More efficient than non-flame retention heads

mild steel

A ferrous metal alloy made from Iron and Carbon. It is tough, ductile and malleable and mainly used for nails, car body panels and construction beams. Mild steel is a type of carbon steel with a low amount of carbon - it is actually also known as "low carbon steel." ... The lack of alloying elements such as those found in stainless steels means that the iron in mild steel is subject to oxidation (rust) if not properly coated.

ceramic capacitor

A fixed value capacitor in which ceramic material acts as the dielectric. Not good in high vibration applications since just tapping the capacitor with your finger will produce a piezoelectrical voltage. So not gonna find it in any concert equipment.

eddy current

A looping of any fluid. Resulting from the fluid deviating from the main path. The fluid can be water, air, liquid, vapor, fields, etc.

What do you need to produce electricity?

A magnet and wire shaft (rotor). Just chop the magnetic flux and you'll induce a voltage. All you need is some method to spin the shaft; it could be a wind mill, water wheel, nuclear, etc.

serpentine belt

A ribbed drive belt that drives more than one engine accessory.

transistor

A small electronic device used in a circuit as an amplifier or switch. device used to produce and control logic gates

Solar thermal collector

A solar thermal collector collects heat by absorbing sunlight. The term "solar collector" commonly refers to a device for solar hot water heating, but may refer to large power generating installations such as solar parabolic troughs and solar towers or non water heating devices such as solar air heaters.

bimetallic thermometer

A temperature-measuring device usually consisting of two dissimilar metals that expand and contract differentially as the temperature changes.

absorption chiller

A vapour absorption system uses heat sources like steam, exhaust gas, hot water etc to produce cooling. This can be used for space cooling as well as process cooling in various industries like food processing, beverages, chemical processing, pharmacies, textile, breweries, semiconductor etc. A compression chiller uses electricity as a power source. Compression cycleEvaporator->Compressor->Condenser->Expansion Valve->Evaporator->... Absorption CycleEvaporator->Absorber->Pump->Generator->Condenser->Evaporator->... In an absorption system, the evaporator is where the refrigerant gets evaporated due to lower pressure at a lower temperature by using the heat from the chilled water and thus cooling the chilled water. The refrigerant vapours are then absorbed by the working fluid (because of its affinity towards refrigerant vapours) in the absorber. The dilute solution is pumped to the generator where by a heat source like steam,exhaust gas,hot water etc the refrigerant gets boiled out (separated) from the dilute solution. This refrigerant condenses in the condenser (using cooling water from the cooling tower) and the condensed refrigerant falls into the evaporator and the cycle continues. The solution which was dilute now becomes strong (as the refrigerant has been boiled out) and falls into the absorber and absorbs the refrigerant vapours. If there is waste heat available (like exhaust gas, excess steam, oil vapours, hot water from process) the cooling produced becomes extremely economical which is a major advantage of the vapour absorption system. Some other advantages are low power consumption (hence less electricty costs), less maintenance costs (as fewer number of moving parts compared to a compression system and good performance at part load. On the other hand vapour absorption systems have higher initial costs (though lower running costs) and require a larger cooling tower.

ANSI

American National Standards Institute: A private, non-profit organization that coordinates the development and use of voluntary consensus standards in the United States.

ASHRAE

American Society of Heating, Refrigerating and Air-Conditioning Engineers

How a transformer works?

An alternating potential difference across the first coil causes an alternating current to flow, creating a continuously changing magnetic field in the iron core, which induces an alternating potential difference across the ends of the secondary coil. It is only possible to do with AC voltage since its magnetic field pulses back and forth between polarities. With DC voltage the magnetic field is constant meaning it will not move electrons in the secondary of the transformer. The only way you could get DC to work with a transformer is by flicking the power on and off to allow the magnetic field to rise and fall continuously.

atom width

An atom is a million times smaller than the thickest human hair. The diameter of an atom ranges from about 0.1 to 0.5 nanometers (1 × 10−10 m to 5 × 10−10 m).

isolation valve boiler

An isolation valve is a valve in a fluid handling system that stops the flow of process media to a given location, usually for maintenance or safety purposes. They can also be used to provide flow logic (selecting one flow path versus another), and to connect external equipment to a system.

armature reaction

Armature reaction is effect of armature flux on main field flux. Basically there are two windings in a dc motor - Armature winding (on rotor) and field winding (on stator). When we excite the field winding, it produces a flux which links with the armature. ... This is referred to as armature reaction.

Demand controlled ventilation (DCV)

Demand controlled ventilation (DCV) is an automatic adjustment of ventilation equipment according to occupant choice. DCV is a control method that modulates the volume exchange of fresh or outside air into an enclosed space by mechanical air conditioning equipment. Usually hooked up to a sensor that will open a damper or economizer damper when a set amount of CO2 or CO is reached. Used in office buildings, movie theaters, etc.

DOE

Department of Energy

Is Nichrome better than kanthal?

Conclusion: The wire you like is going to vary from person to person. The benefits of Kanthal are it is more sturdy, it can take more heat, and a lot of people find it easier to wrap with because it stays in place better. Nichrome 80 heats up faster, loses its heat faster, and doesn't contain iron.

In what way is electrical tape different from regular tape?

Electrical tape has higher dielectric strength and thickness guaranteed so that you will not get shocked. It is intended to be used to insulate electrical wires. The dielectric strength is 1150 V/mil and its 7 mil thick (Scotch 33). Its insulation should withstand several thousand volts. Operating Temperature rating is 0 to 220°F.

Difference between expansion and compression tank

Expansion tank is vented and usually connected to water supply to provide boiler with makeup water. Compression tank is pressurized and absorbs fluctuations in water pressure caused by water temp changes.

why use flare fittings over compression fittings?

Flare connections are used when water pressure is high, or for gas distribution: applications with higher pressures than a compression fitting could handle. Flare for high pressures.

why does freezing food preserve it?

Freezing delays spoilage and keeps foods safe by preventing microorganisms from growing and by slowing down the enzyme activity that causes food to spoil. As the water in the food freezes into ice crystals, it becomes unavailable to those microorganisms that need it for growth.

HFO-1234yf

GWP of 4 Latent heat vaporization: 77 BTU/lb C3H2F4 Starting in 2011, automakers must meet the EU's MAC Directive, which prohibits the use of refrigerants with a global warming potential (GWP) higher than 150 in new vehicle types This Directive created a need for a globally-compliant replacement for R134a refrigerant, and it was a challenge that Honeywell worked to solve for several years. Honeywell is offering a drop-in or near drop-in solution called HFO-1234yf. Its GWP of 4 is 97% lower than the new EU regulation requires and 99.7% lower than R134a HFO-1234yf has an atmospheric lifetime of only 11 days - compared to 13 years for R-134a and more than 500 years for carbon dioxide. Unlike HFCs and CFCs, which take decades to decompose, HFO-1234yf does not persist in the atmosphere. Quite simply, vehicles using highly energy-efficient HFO-1234yf refrigerant will use less fuel and produce fewer emissions than many of the existing alternatives. HFO-1234yf performs well when used with polyalkylene glycol (PAG) and with polyol ester lubricants. Most automotive original equipment manufacturers have chosen specific PAG lubricants for their systems. For non-automotive applications, most compressor manufacturers recommend specific polyol ester lubricants. Users should check with the equipment manufacturer for the recommended lubricants for their system. Cylinders containing HFO-1234yf should be kept out of direct sunlight, especially in warm weather. Liquid HFO-1234yf expands significantly when heated, reducing the amount of vapour space left in the cylinder. Once the cylinder becomes liquid-full, any further rise in temperature can cause it to rupture or explode, potentially resulting in severe damage and injury. A cylinder should never be allowed to get warmer than about 50°C.

Galvanic isolation

Galvanic isolation is a principle of isolating functional sections of electrical systems to prevent current flow; no direct conduction path is permitted.[1][2] Energy or information can still be exchanged between the sections by other means, such as capacitance, induction or electromagnetic waves, or by optical, acoustic or mechanical means. Galvanic isolation is used where two or more electric circuits must communicate, but their grounds may be at different potentials. It is an effective method of breaking ground loops by preventing unwanted current from flowing between two units sharing a ground conductor. Galvanic isolation is also used for safety, preventing accidental current from reaching ground through a person's body. Transformers couple by magnetic flux. The primary and secondary windings of a transformer are not connected to each other (an autotransformer has a conductive connection between its windings and so does not provide isolation). The voltage difference that may safely be applied between windings without risk of breakdown (the isolation voltage) is specified in kilovolts by an industry standard. The same applies to transductors. While transformers are usually used to change voltages, isolation transformers with a 1:1 ratio are used in safety applications. If two electronic systems have a common ground, they are not galvanically isolated. The common ground might not normally and intentionally have connection to functional poles, but might become connected. For this reason isolation transformers do not supply a GND/earth pole.

tig welding

Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The main difference between these methods is the technique used. With MIG welding, a wire electrode is continuously fed through the spool gun to create the weld. TIG welding requires the welder to feed a separate filler material onto the weld with one hand while operating the torch with the other TIG can be used to weld copper, titanium, even two dissimilar metals, and is handy for making tricky welds (e.g. s-curves, or welds on round things).. TIG generates heat via an arc of electricity jumping from a (tungsten metal) electrode to the metal surfaces you intend to weld - usually aluminum or steel.

HFO refrigerant

HFO stands for hydrofluoro olefin. Opteon™ YF (HFO-1234yf) is a low global warming potential (GWP) refrigerant for use in automotive air-conditioning systems. Opteon™ YF (HFO-1234yf) has a chemical structure of CF3CF= CH2 2,3,3,3-tetrafluoropropene. YF has a GWP of just 4

what does it mean for a boiler to be waterlogged?

If the compression tank is allowed to fill with water, pressure in the boiler increases because there is no longer any air to compress. This will cause the safety relief valve to open.

IBC

International Building Code International Code Council (ICC)

cloud point

The temperature below which diesel or biodiesel appear cloudy owing to the formation of small crystals. The presence of these crystals thickens the fuel and clogs filters and injectors. point at which small wax crystals begin to form in fuel oil

How to wire a 3 phase 9 lead motor in star/wye?

Label 1 at top and rotate clockwise with sequential numbers The reason you can swap between high and low voltage operation on the same motor is because when it is in low voltage operation you short between one set of the inductive windings which means less magnetism is produced, in turn allowing the motor to operate at a lower level.

MIG vs TIG welding

MIG can weld thicker metals faster than a TIG weld. If the metal you're using is thin, TIG could be a better option. MIG welding works with most types of metals. ... TIG welding is also compatible with these metals but works better with thinner gauge materials. MIG welding was developed during World War II as a fast, portable process to create strong, durable joints. Today it is used in many shop and factory applications as well as by home hobbyists and welding enthusiasts. Learn how it works. MIG welding uses a machine to feed a wire through a contact tip into a MIG gun

mig welding

MIG welding is an arc welding process in which a continuous solid wire electrode is fed through a welding gun and into the weld pool, joining the two base materials together. A shielding gas is also sent through the welding gun and protects the weld pool from contamination. In fact, MIG stands for metal inert gas. The main difference between these methods is the technique used. With MIG welding, a wire electrode is continuously fed through the spool gun to create the weld. TIG welding requires the welder to feed a separate filler material onto the weld with one hand while operating the torch with the other

What are Maxwell's Equations?

Maxwell's equations is a system of four equations describing the interplay between electric fields, magnetic fields, electric charges, and electric currents. I'll write them out in their differential form to look cool, but I'll also explain what the equations tell us.

slip ring

Metal rings connected to the rotation coil in a generator. They make electrical contact with an external circuit. a device with attached brushes that allows the circuit to remain stationary while the armature rotates without breaking the electrical contact between them I did line maintenance on 1.5 MW turbines. Amongst which is annual replacement of brushes. There are five (5) such brushes; one for each of the phase, one for neutral and one ground. The slip rings are copper for each phase and neutral while the ground is stainless steel. One such project was early failure because of a out of round S/S ground ring. The brush was burned way back and the ground arced to the RTD's shield (resistive thermal device).

3 phase transformer core

Most common to use a shared core between the three phases

NOWL

Normal Operating Water Level

why are motor brushes called brushes?

Old motors/generators used copper brushes before carbon/graphite brushes existed

steam table

PT chart for water

Pulse Width Modulation (PWM)

Pulse width modulation, or pulse-duration modulation, is a method of reducing the average power delivered by an electrical signal, by effectively chopping it up into discrete parts. The average value of voltage fed to the load is controlled by turning the switch between supply and load on and off at a fast rate.

quartz heating

Quartz heating is a type of radiant heating, commonly referred to as short wave infrared heating. Radiant heating uses infrared waves to directly heat the surfaces of objects. All objects emit and absorb infrared heat, which is part of the electromagnetic spectrum with a frequency below visible light. Hotter objects will radiate more of this heat. This is the basis of the technology for most quartz heaters. A quartz heater is a common type of infrared heater and the creation and subsequent release of heat from the heater is made by the heating element, enclosed in a quartz tube. The heating element produces heat at the necessary wavelength to create the appropriate level of intensity to heat the specific material required. The purpose of the quartz tube is to protect the heating element and also to stop the escape of convection heat. The principle of quartz heating works with the heating element becoming very hot and the quartz tube experiencing a sudden build up of heat. When the quartz tube reaches the appropriate temperature, the heat is emitted out of the quartz tube. The wavelength of heat produced from this process has been acknowledged as ideal for the human body. The infrared heat is directly absorbed by the people and objects near the quartz heater and very little heat is absorbed by the air, due to the infrared spectrum being almost completely outside the absorption spectrum of air.

R-744

R744 / R-744 is hence the standard nomenclature for CO2 used as a refrigerant: "7" indicates the natural fluid while "44" refers to the fluid's weight. The term R744 is applied when referred to the refrigerant itself, and CO2, and/ or CO2 Technology is used when referring to an application or use. 3.

stick welding

Shielded metal arc welding, also known as manual metal arc welding, flux shielded arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld. Stick welding is a form of welding that uses electricity to melt a metal filler rod/electrode/stick (electrode is the proper term) that melts both the metal joint and electrode all at once to fuse two pieces of metal together and fill the joint with filler metal at the same time.

What is silica gel and how does it work?

Silica Gel, SiO2, is essentially a synthetic, microporous form of sand. It's produced in small, irregular beads that contain thousands of microscopic cavities. These cavities create a low vapor pressure inside it, which makes the beads hygroscopic - i.e. they tend to adsorb water molecules from the humid air, which has a higher vapor pressure. In a closed, humid container, pressure will be exerted on the container by the water molecules - this is vapor pressure. The air in the container has lots of water molecules, ergo it has a high vapor pressure. Because of its huge surface area due to all the microscopic pores, the dry silica will have a low vapor pressure inside it because there is no water there yet. The water molecules in the air will eventually be adsorbed (stuck) into the pores of the gel, because in closed systems, pressure will always try distribute itself equally. The gel will stop adsorbing water when equilibrium is reached, and the water vapor pressure is equal in the gel and the air. Logically, the more humid the air is, the more water will also be absorbed before equilibrium is reached. The gel is capable of holding up to roughly 40% of its own weight in water. Silica is especially useful as a desiccant because it is cheap to produce, nontoxic and nonreactive, and can keep products dry during transport that would otherwise be harmed by moisture.

Step up vs. Step down transformers

Step up: Voltage increases, current decreases Step down: Voltage decreases, current increases

555 timer

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element. Derivatives provide two (556) or four (558) timing circuits in one package.

How do you neutralize an armature reaction?

The compensating winding are basically used to neutralize the armature flux in the pole arc region which will otherwise cause sever distortion of main field flux. By using high reluctance pole tips, reduction in armature flux and using strong main field flux poles we neutralize the armature reaction.

servo motor encoder

The encoder is a sensor that notifies the driver of the speed and position of the motor. The encoders (position detectors) used in the servo motor can be structurally classified as "incremental encoders" and "absolute encoders".

one boiler horsepower

The evaporation of 34.5 lb of water/hr from and at a feedwater temperature of 212°F 33,472 BTU/hr

how to check for water in oil tank

To check for water in your oil tank, apply some of the water detection paste on a stick and gently place it inside the tank until it hits the bottom. Leave it for approximately 30 seconds and then carefully take it out of the oil tank. You will know if water is present if the paste has changed colour.

Transformer Iron Core

Transformer iron cores are laminated to reduce losses due to eddy currents. The reason transformers have ferromagnetic cores in the first place is to reduce losses from the initial magnetic field from the primary wire. The iron core acts as a guide for the magnetic field from the primary to the secondary.

Urethane foam

Urethane Foam. Urethane Foam - Rempac Foam Corporation. Urethane foam is a versatile and widely used type of foam material. Commonly used to refer to a material made from polyurethane, urethane foam can be both rigid and flexible and in a broad range of industries such as construction, furniture, automotive and medical .

amalgam

a combination of diverse elements; a mixture a mixture or blend.

magnetometer

a device that can detect small changes in magnetic fields an instrument used for measuring magnetic forces, especially the earth's magnetism.

torque

a twisting force that tends to cause rotation. Torque, moment, moment of force or "turning effect" is the rotational equivalent of linear force. The concept originated with the studies of Archimedes on the usage of levers. Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object.

boiler accumulation test

all discharge piping is closed and the boiler is operated until the safety relief valve pops open

Faraday cage

an electrically conductive wire mesh or other conductor woven into a cage that surrounds a room and prevents electromagnetic signals from entering or leaving Faraday cages cannot block stable or slowly varying magnetic fields, such as the Earth's magnetic field (a compass will still work inside). To a large degree, though, they shield the interior from external electromagnetic radiation if the conductor is thick enough and any holes are significantly smaller than the wavelength of the radiation. For example, certain computer forensic test procedures of electronic systems that require an environment free of electromagnetic interference can be carried out within a screened room. These rooms are spaces that are completely enclosed by one or more layers of a fine metal mesh or perforated sheet metal. The metal layers are grounded to dissipate any electric currents generated from external or internal electromagnetic fields, and thus they block a large amount of the electromagnetic interference. See also electromagnetic shielding. They provide less attenuation of outgoing transmissions than incoming: they can block EMP waves from natural phenomena very effectively, but a tracking device, especially in upper frequencies, may be able to penetrate from within the cage (e.g., some cell phones operate at various radio frequencies so while one cell phone may not work, another one will). Michael Faraday showed through his ice pail experiment that all charge resides on the outside of a hollow conductor. This means that if a person is inside a Faraday Cage then the charge is on the outside, and theoretically if the person touched the inside, would not get electrocuted. (But I wouldn't test it). This is why it is safe to be inside a car during a lightning storm. Or inside a metal suit (that is earthed) when working on high voltage electrical wires. Also used in RF receivers to block RF from leaking or interfering.

Lenz Law

an induced current is always in a direction which will oppose the motion or change that caused it Lenz Law states that "The direction of the induced current is such that it opposes the change that has induced it." In other words, Effect Opposes the Cause. Here effect is induced current and cause is changing magnetic flux.

try lever test

boiler test where you manually open the pressure relief valve to make sure it works boiler must be at a minimum of 5 psig before you test

Capacitive coupling

electricity transferred between two conductors that are separated by insulation Capacitive coupling is the transfer of energy within an electrical network or between distant networks by means of displacement current between circuit(s) nodes, induced by the electric field. This coupling can have an intentional or accidental effect. In its simplest implementation, capacitive coupling is achieved by placing a capacitor between two nodes.[1] Where analysis of many points in a circuit is carried out, the capacitance at each point and between points can be described in a matrix form. In analog circuits, a coupling capacitor is used to connect two circuits such that only the AC signal from the first circuit can pass through to the next while DC is blocked. This technique helps to isolate the DC bias settings of the two coupled circuits. Capacitive coupling is also known as AC coupling and the capacitor used for the purpose is also known as a DC-blocking capacitor.

boiler u-tube siphon

essentially a p-trap. used to protect boiler gauges and controls from high pressure steam by trapping condensate in bottom

general electric

in fear of technological competition, they created one of the first corporate laboratories in 1900, increasing corporate research and development labs, but causing a decline in government support in research. This attracted more skillful researchers and decentralized the sources of research funding.

boiler pop test

increase boiler pressure until the safety relief valve pops open. once it pops system firing rate is reduced.

whats heat tape made of?

insulated high resistive wire

drop leg

line between condenser and receiver

combustion chambers

make sure they are designed to fit the flame and not allow for eddy current formation or flame impingement

MAWT

maximum allowable water temperature

CO2, O2, and Excess air

oil burner

boiler pigtail siphon

protects gauges and controls from high pressure steam

valve chattering

rapid opening and closing of a valve usually referenced towards safety valves

boiler water column

reduces turbidity of water so it can be seen correctly in the gauge glass

electric boiler

steam is generated using electricity rather than the combustion of a fuel. More expensive than gas run boilers but are simple and easy to use use either resistance strip heaters or an electrode

how to frontseat service valve

turn clockwise all the way. normal system operation has the valve backseated

hot water reset control

used on hot water boilers. has a temperature sensor outside and one on the hot water supply. it will adjust the water temp of the boiler depending on how warm/cool it is outside

Barometric Draft Regulator (Barometric Damper)

used on the sheet metal flue exhaust on an oil heat system. has a counterweight that can be adjusted to increase or decrease dilution air used to adjust draft above the flame

interpole

used to fix armature reaction an auxiliary pole of a commutator placed between the main poles to increase its efficiency. Interpoles are used in DC Machines to reduce the effect of armature reaction and self induction, mainly in winding at commutators,of DC motors. Interpoles are connected in series with armature winding so that as the armature current changes the flux due to interpoles chances accordingly. Interpoles are temporary magnets,generally placed in between two consecutive poles.