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Hydronics Heating and Cooling complete Study Guide solution What is the definition of human comfort relative to temperature? When you feel neither warm nor cool. pg. 1 Which type of hydronic system would use gravity flow? Low temperature heating. pg. Describe a hydronic system. Heating and cooling system that uses water or HTF as a heat transfer medium. pg. Brine or a water/glycol mixture is commonly referred to as___. HTF pg. In which year did Willis Carrier patent the dew point control system? 1907 pg. How many BTUs are required to heat one lb of water from 32F to 212F? 180 BTUs pg. 22 In order to provide accurate indoor temperatures the heat supply to the building must be equal to___. Heat loss of the building pg. 5 What are the 4 types of heat transfer Conduction, convection, radiation, and evaporation. pg. 14 Calculate the GPM for an 80MBH heat load using water as the HTH with a change in temperature of 20F. GPM=btuh/(Delta T X specific heat X 500) GPM=80,000/(20 X 1 X 500) GPM=80,000/10,
GPM=
pg. 22 How is TEL (total equivalent length) measured and calculated? Measure the longest circuit and add 50% for fittings and terminal units. pg. Which type of heat, when added or removed from a substance creates a change of state? Latent heat pg. 18 Define humidity. The amount of moisture in the air. pg. 24 What is dry bulb temperature? Temperature of air taken with a standard thermometer. pg. 25 Which tool is used to determine relative humidity? Sling psychrometer Pg. 34 How is rate of flow measured? Gallons per minute (GPM) pg. 48 Select 3 types of heat transfer. Radiation, convection, conduction pg 15 Which heat transfer describes the condition when a body loses heat to cooler surfaces? Radiation pg 15 What is the pressure of 1 ft of water (vertical)? 0.433 psig/ft pg 45 ___ is any pressure less than atmospheric.
Latent heat pg 18 By controlling the rate of ___, hydronic heating and cooling systems allow the body to be comfortable. Heat loss pg 14 What is absolute pressure Gauge+atmospheric pressure pg 42 What is the formula for calculating pump gpm? Heat-loss/ 10, pg 47 What is the general equation for calculating sensible heat change of fluids? Btu=gpm X specific heat X change in temp. X 500 pg 21 How is vacuum measured? inches of mercury (in Hg) pg 42 What is the maximum design pressure for a low temperature boiler (ASME)? 160 psig pg 51 What would be the correct valve that would be used to regulate the rate of HTF flow in a piping system? Balancing valve pg 81 Name the 4 main components of a chiller system. Compressor, condenser, evaporator, refrigerant. pg 87 These devices would be included in a make-up water system. Pressure reducing valve, back-flow preventor, isolation valve pg 75 What is LWCO?
Low-water cut-off pg 71 Which boiler has the highest output rating? -Cast Iron -Scotch Marine -Condensing -Electric Electric pg 61 What device is used to protect a potable water system from cross connections? Backflow preventer pg 77 A condenser acts as a type of . Heat exchanger pg 87 Low-pressure boilers are classified by. 15 psig steam and 160 psig water pg 51 Low-pressure boilers have a specific pressure and temperature limits; what is the maximum pressure temperature limit for these boilers (ASME)? 15 psig steam, 160 psig water at 250F pg 51 What type of device is attached to the boiler to assist in the management of air in the hydronic system? Boiler fitting pg 70 What type of boiler uses microprocessor-controlled combustion which automatically adjusts air-fuel mixture? Condensing pg 59 What device protects the boiler from pressures above maximum design pressure? Relief valve pg 67
What are the 3 functions of a triple duty valve? Flow control (balancing), check valve, isolation When connecting a make-up water fill line, what is the best location? The point of no pressure change Which impeller is most efficient with clear liquids? How many pipe diameters of straight pipe do you need between the wye strainer and the suction 5 Which consideration is most important when starting a pump for the first time? Check alignment of pump and motor Pumps, when subjected to a lift task must be___ before starting the motor. Primed What describes an impeller that has vanes attached to a hub that is not enclosed or supported by a shroud on either side? Open impeller What describes a hydronic system that is sealed to prevent the entrance of air from the atmosphere? Closed system Why is glycol not used at 100% concentrations? Very high viscosity, and does not transfer heat well. What pump is used most often for a closed hydronic piping system? Centrifugal In a primary-secondary pumping arrangement, where is the largest circulator installed? Primary loop A hydronic system uses___ to transfer heat. HTF Where should you install a triple duty valve? Discharge side of the circulator
What is the maximum spacing recommended for the closely spaced tees on a primary/secondary system? 4 pipe diameters What are the 2 types of pump misalignment that must be checked? Angular and parallel What is the violent action of vapor bubbles in a centrifugal pump? Cavitation When calculating pump capacity in an open system you must___ Add static head to piping resistance A pump is not moving any fluid, what should you check? Pump is primed What is the maximum theoretical lift of a pump? 34' The best place for air separation is at the boiler; why? Air bubbles are larger, and HTF is at a high temperature and low velocity A typical pressure at the top of a hydronic system with the pumps off would be___. 4 psig A system is 7 stories tall and it includes a captive diaphragm expansion tank in the basement, what is the adjusted tank pressure? (10'/floor) 36 psig Ypu have installed a 1" ATFL fitting with a run of 37' to the boiler fitting, what is the correct size of the pipe? (use table 5-10) 1 1/2" Select 3 ways air can exist within a hydronic system. Air pockets, entrained air bubbles, dissolved gases A closed hydronic system has a static head of 30'. what is the cold fill pressure at the pump? 17 psig Which of the following flow rates is best for air removal? -10 fps
Diversion tee What is an ASTM standard for steel pipe? ASTM A Describe a full way valve used to regulate flow in which a threaded stem raises and lowers a wedge shaped disc. Gate valve What valve allows fluid flow in 1 direction? Check valve Copper is often used in hydronic and refrigeration systems; list the 3 types of copper tubing in order of wall thickness. (thickest to thinnest) K, L, M A U-shaped section of piping that absorbs thermal movement is an____. Expansion loop What is the maximum horizontal hanger spacing for 3"polypropylene pipe? 4' ____ prevent piping in horizontal runs from sagging and leaking. Hangers Select the best application for a globe valve in a hydronic piping system. -Isolation, fully opem -Throttling or flow control -Isolation of a pump -When a gate valve doesn't fit Throttling or flow control What piping system is identified by "first supplied, last to connect to the return?" Direct return What is a zone? A circuit that is controlled by one thermostat When using an eccentric reducer in a hydronic system, how is the fitting installed? Flat on top to keep the air moving
What rule applies to the branch takeoffs when piping terminal units on a one pipe system? Should be the same width of the terminal unit To prevent debris from collecting in the heat transfer units, how is the branch piping installed? Top or 45 degrees off main What system has separate heating and cooling functions with dedicated supply and return piping? 4 pipe Which piping designs are 2-type systems? -Series loop and 1-pipe -Direct return and reverse return -How water and chilled water -Closed loop and open loop Direct return and reverse return Which type of fitting is used to reduce the pipe size in a hydronic main? -Concentric -coupling -Eccentric -Ground joint union Eccentric What are the 2 types of a 1-pipe system? Single main, series loop What hydronic device uses chilled HTF in an overhead terminal unit? Chilled beam A radiant panel transfers heat by___. Convection/Radiation An air-handling unit includes which components? Filter section, coil section, fan section Air handling units are used for heating and cooling; what other function is often included? Humidity control The relative humidity of a conditioned space should be___.
Which control system makes decisions based only on the current state of the system and a model of how it should work? Open loop control What is the device used to measure a controlled variable to transmit that measurement to a controller? Sensor Select the term which describes what is monitored or changed by a control system. -Relay -Hysteresis -Variable -Switch Variable Which term describes the range between 2 set-points in which no control action takes place? -Derivative -Gain -Dead-band -Offset Dead-band Which term describes the point at which a control system will start or stop an action? -Dead-band -Set-point -Gain -Offset Set-point When used in conjunction with a controller, the actuator is considered what type of device? Output How many possible states does a digital signal have? 2 When reading differential pressure across a pump, good HTF flow is indicated by____. High pressure differential
Changing characteristics in a hydronic system are known as . Variables What is the definition of hysteresis? The relationship between rate of change of an input and the rate of change of an output. A Pitot tube station measures____. Static and total pressure What describes a formal assessment of the functionality and efficiency of a system? -Balancing -Calibration -Commisioning -Pressure testing Commisioning 1/32" of scale buildup inside can decrease heat transfer by____. 40% What type of glycol has the best heat transfer characteristic? -Algaecide -Isopryl -Ethylene -Propylene Ethylene What glycol is used in a food safe environment? Propylene What is the recommended solution of sodium carbonate used when cleaning a steel pipe? 1 lb/30 gal The Uniform Mechanical Code states that system piping system piping and components shall be tested with a pressure of not less than times the operating pressure and not less than___psig. 1.5/ What condition can act as an insulator and is an accumulation of mineral deposits on metal surfaces? Scale
