Term
| All pneumatic controls require a source of ___, ___, and ___ compressed air. |
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Definition
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Term
| What is the location of the 30 PSIG safety relief valve? |
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Definition
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Term
| What device is added to a duplex air compressor set to ensure that equal wear would occur on each compressor? |
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Definition
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Term
| What are two types of lubrication system used in air compressors? |
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Definition
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Term
| To operate properly, what should a compressor's run time be? |
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Definition
| 1/3 to 1/2 the operating time. |
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Term
| What is the value of scim used for in the pneumatic control industry? |
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Definition
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Term
| Pressure drop is measured as the difference between the ___ pressure and the ___ pressure of a control valve. |
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Definition
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Term
| What part of a valve actuator assembly will most likely fail first? |
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Definition
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Term
| How often should a control valve be replaced? |
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Definition
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Term
| State the valve piping rule. |
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Definition
| The plug must always close against the flow. |
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Term
| Explain the term "unison operation". |
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Definition
| All dampers move at the same time. |
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Term
| An air to close valve is normally ___. |
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Definition
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Term
| Which type of damper should be used in a hot deck/cold deck application? |
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Definition
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Term
| What is the fail safe position for a return air damper? |
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Definition
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Term
| In a rod and tube measuring element, the rod is made of ___ and the tube is made of ___. |
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Definition
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Term
| What type of measuring element is a helix? |
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Definition
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Term
| The element that varies the pressure of the control air to position the controlled device is called the ______ element. |
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Definition
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Term
| What is the proper control name for a freezestat? |
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Definition
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Term
| What type of controller should be used when the point of temperature measurement is affected by vibration at the controller's location? |
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Definition
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Term
| What is the action of a thermostat used with a normally closed chilled water valve? |
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Definition
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Term
| Insertion controllers are usually mounted in a ___. |
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Definition
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Term
| The range of temperature above and below the set point that allows a proportional controller to open and close is called its ___. |
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Definition
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Term
| Which wall should a room thermostat never be mounted on? |
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Definition
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Term
| Turning the set point knob on a thermostat to a lower set point stimulates a rise or fall in room temperature? |
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Definition
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Term
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Definition
| Pressure on the inside of a duct. |
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Term
| Which pressure inside of a duct cannot be directly measured? |
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Definition
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Term
| What is the name of the device mounted on a duct to sense static pressure? |
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Definition
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Term
| An EP operates a ____ switch when an ____ signal is applied to it. |
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Definition
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Term
| On a control drawing an EP is connected electronically to "LSFS". What do the letters LSFS stand for? |
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Definition
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Term
| A PE operates an ____ switch when a ____ signal is applied to it. |
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Definition
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Term
| Water build up in a receiver tank will not affect the run time of a compressor. |
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Definition
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Term
| The bottom port of a 3 way mixing valve is NO. |
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Definition
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Term
| When installing a humidistat, it is important to touch the hydroscopic element to activate it. |
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Definition
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Term
| A system that recycles its process or medium and maintains control of it. |
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Definition
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Term
| The end device in a control system. |
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Definition
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Term
| The medium being controlled by a receiver-controller where the transmitter is located. |
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Definition
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Term
| A manual pneumatic switch for adjusting air pressure output from zero to 100%. |
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Definition
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Term
| The action of a controller that increases the output pressure as the medium being sensed increases. |
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Definition
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Term
| An external input to a receiver-controller that can reset the set point of a controller. |
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Definition
| Control point adjustment (CPA). |
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Term
| An auxiliary device that changes a pneumatic signal to an electrical signal. |
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Definition
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Term
| The substance being sensed or controlled (also called a process). |
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Definition
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Term
| The condition a controlled device or control system assumes with a loss of a signal (air or electrical). |
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Definition
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Term
| The order in which a control system executes the sequence of operation. |
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Definition
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Term
| What is the most important concept to consider in the control of the heating, cooling, and ventilating of all types of building? |
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Definition
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Term
| What are four advantages of using pneumatic controls? |
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Definition
1. Simple operation.
2. Flexible application.
3. Built-in safety.
4. Reliable service. |
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Term
| In which kind of loop would you find the effect of feedback? |
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Definition
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Term
| What are the three basic parts of an automatic closed control loop? |
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Definition
1. Controller
2. Controlled device.
3. Process. |
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Term
| Plant air is suitable for use with pneumatic controls. |
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Definition
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Term
| What is the device that reduces the dew point of control air? |
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Definition
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Term
| What causes an oil filter to get clogged with dirt? |
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Definition
| Reversing its position from downstream to upstream. |
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Term
| What two places are safety relief valves installed? |
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Definition
| The receiver and downstream of the PRV. |
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Term
| What weight and type of oil should always be used in a control air compressor? |
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Definition
| 20 or 30 weight non-detergent oil. |
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Term
| What annual preventative maintenance must be done to an oil-less air compressor that is not required on oil lubricated types? |
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Definition
| Replace the rings, skirts, and valves. |
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Term
|
Definition
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Term
|
Definition
| (on time/cycle time) X 100 |
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Term
| List four operating features that make an instrument air compressor better than a general use compressor. |
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Definition
1. Low operating RPM.
2. Cooler running temperature.
3. Less oil carryover.
4. Longer life. |
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Term
| A coalescent filter is a type of ___ filter. |
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Definition
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Term
| What are four classifications of pneumatic controls? |
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Definition
1. Two-way NO.
2. Two-way NC.
3. Three-way mixing.
4. Three-way diverting. |
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Term
| What two letters are used in control valve sizing formulas to denote capacity index? |
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Definition
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Term
| What pressure drop should be used in the formula for sizing a heating water control valve if the pressure drop is not specified? |
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Definition
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Term
| What are four major parts of a valve actuator? |
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Definition
1. Housing.
2. Cup.
3. Diaphragm.
4. Spring. |
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Term
| What are the seats of a balanced valve made of? |
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Definition
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Term
| What is wrong with a pneumatic control valve that is hammering? |
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Definition
| It isn't closing against the flow. |
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Term
| List the four parts of a control valve that make up it's trim? |
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Definition
1. Seat.
2. Disc.
3. Plug.
4. Stem. |
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Term
| Name three kinds of packing commonly used in pneumatic control valves. |
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Definition
1. Rope.
2. Cone or ring.
3. U-Cup. |
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Term
| How many inlets and outlets does a three-way mixing valve have? |
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Definition
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Term
| What is the meaning of the term "spring range"? |
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Definition
| The range of control air pressures the spring will operate through. |
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Term
| What is spring range shift? |
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Definition
| A change in the spring of a control valve if the control signal is lost to the actuator. |
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Term
| What kind of packing is used in a butterfly valve? |
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Definition
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Term
| What two parts of control valve trim give tight close-off? |
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Definition
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Term
| Linear and equal percentage are the names of what kind of control valve? |
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Definition
| Contour plug or skirted V port. |
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Term
| What kind of plug is used on a quick-opening style control valve? |
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Definition
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Term
| Which part of the valve trim does not move? |
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Definition
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Term
| Metal to metal seat valves do not have tight close off. |
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Definition
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Term
| The bottom port of a three-way diverting valve is normally open. |
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Definition
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Term
| Valve actuators have rubber diaphragms. |
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Definition
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Term
| List the five parts of a damper actuator: |
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Definition
1. Housing.
2. Spring.
3. Cup.
4. Diaphragm.
5. Push rod. |
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Term
| What are the two types of multiblade control dampers? |
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Definition
| Parallel blade and opposed blade. |
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Term
| Which type of damper should be used in a mixing box? |
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Definition
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Term
| What problem with airflow will occur if the mixing box dampers are the opposed blade type? |
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Definition
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Term
| Which type of damper is generally used to control static pressure at an air handling unit main fan outlet? |
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Definition
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Term
| What is the fail safe position for an outside air damper? |
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Definition
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Term
| How often should the bushing of a damper be lubricated? |
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Definition
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Term
| Where are single blade dampers used? |
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Definition
| VAV, CAV, and terminal units. |
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Term
| Opposed blade dampers are best suited for... |
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Definition
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Term
| What important feature is found on dampers used for smoke control? |
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Definition
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Term
| An air blender is a modulating damper used in the mixing box. |
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Definition
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Term
| Manufacturers supply control damper in both normally open and normally closed configurations. |
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Definition
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Term
| Dampers can be mounted with the blades horizontal or vertical. |
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Definition
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Term
| A device that measures a condition and takes a control action based on a change in that condition is a ____. |
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Definition
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Term
| What are three of the most common measuring elements? |
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Definition
| Temperature, pressure, and humidity. |
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Term
| Name three types of controlling elements. |
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Definition
| Bleed, non-bleed, and pilot bleed. |
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Term
| What are the two metals used to make a bimetal strip? |
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Definition
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Term
| A bellow can be found in what two types of measuring elements? |
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Definition
| Temperature and pressure. |
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Term
| Name three types of pressure measuring elements: |
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Definition
| Bellow, diaphragm, Bourdon tube. |
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Term
An enthalpy controller has two measuring elements.
The ___ element measures ____ and the ___ element measures ___. |
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Definition
| bimetal;temperature. membrane;humidity. |
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Term
| When mounting a safety low-limit, where should the housing be located in reference to the capillary? |
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Definition
| At the highest point above the capillary. |
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Term
| Give the definition for reverse action. |
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Definition
| An increase in the controlled variable will cause a decrease in the BLP to the control valve. |
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Term
| A direct acting thermostat would be used with a two-way hot water valve that is normally... |
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Definition
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Term
| Immersion controllers are usually mounted in an... |
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Definition
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Term
| Which controller is hygroscopic in the way it operates? |
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Definition
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|
Term
| Which controller mode of operation has a differential? |
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Definition
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Term
| What are the three pressures at work inside a duct? |
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Definition
| Static, velocity, and total. |
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Term
| List the names of the four ports on a pneumatic two-position switching relay. |
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Definition
1. Pilot.
2. NO Port.
3. NC Port.
4. C Port. |
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Term
| What two kinds of pilot signals will activate a special pneumatic snap-acting two-position relay? |
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Definition
| Two position and proportional. |
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Term
| What proportional relay can be added to a control valve to prevent spring range shift? |
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Definition
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Term
| Gradual pneumatic switches are used to manually position devices, which require ___ control. |
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Definition
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Term
| How far should a flow switch be mounted from the nearest fitting? |
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Definition
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Term
| A pneumatic flow switch is a two-position device. |
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Definition
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Term
| A single pressure thermostat will operate on a range of single main air pressures from ___ psig to ___ psig. |
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Definition
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Term
| Other than temperature controllers, what other kinds of controllers must operate on a dual pressure main air. |
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Definition
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Term
| In a direct acting thermostat, the heating valve is normally ___ and the cooling valve is normally ___. |
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Definition
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Term
| How much pressure must separate the two main air pressures in a dual pressure main? |
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Definition
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Term
| What is the purpose of the external level or button on a day/night thermostat? |
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Definition
| To manually override the system. |
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Term
| Day/night thermostats change their ___ |
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Definition
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Term
| Heat/cool thermostats change their ___ |
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Definition
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Term
| How can automatic changeover between summer and winter operation be accomplished? |
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Definition
| By replacing the manual switch with a controller and two position relay. |
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Term
| Name four different devices which can be used to change the main air pressure supplied to a system. |
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Definition
1. Dual pressure PRV.
2. Three-way switching valve.
3. Pneumatic switch relay.
4. Two-position pneumatic. |
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Term
| How is a three-way air valve different from a three-way water valve. |
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Definition
| Three-way air valves are not interchangeable. |
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Term
| A thermostat with a remote-measuring element connected to it with plastic tubing operates like a ___ and ___. |
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Definition
| Temperature transmitter; receiver controller. |
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Term
| How far away from the thermostat can a remote measuring element be located using plastic tubing. |
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Definition
| Up to 200' away from the thermostat. |
|
|
Term
| What is a limited control range thermostat? |
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Definition
| Will limit the heating space and cooling space temperatures. |
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Term
| What is another name for a zero energy band thermostat. |
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Definition
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|
Term
| Where would a troffer thermostat be mounted? |
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Definition
| In a slot diffuser, light troffer, or return grille. |
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|
Term
| What is the most common reason for using troffer thermostats? |
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Definition
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|
Term
| Defined as a constant swing in temperature well above and below the limits of the differential or throttling range. Adjusting the differential or throttling range to too small a value causes this. |
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Definition
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Term
| If the differential or throttling range is set too wide, the controller cannot hold a steady value, causing this. |
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Definition
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Term
| Also called a sensor, it will provide remote control or indication, but can not directly control any device. |
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Definition
|
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Term
| Defined as the point at which the set point and the control point are the same. |
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Definition
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|
Term
| The most common electronic transmission signal is... |
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Definition
|
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Term
| This receives a pilot pressure signal and increases the volume and/or changes the value of the output pressure to the final controlled device. |
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Definition
| The amplification or bias start relay. |
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Term
When a proportional controller must operate several valve and/or damper actuators at the same time, the the control air signal will be slow to change because the actuators must fill with air in order to operate the valve or damper.
This slowness is called... |
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Definition
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