Temperature Sensing And Control Devices

Front 1

bi metal

Back 1

2 metals that expand and contract when exposed to heat

Front 2

strip type bi metal

Back 2

to strips then connect when cold see pg 2

Front 3

a spiral or coil of bi metal that loosens and tightens?

Back 3

spiral type bimetal

Front 4

the fastest bimetal type is

Back 4

disc because it snaps in and out of place

Front 5

bellows type temperature sensing device is wtf?

Back 5

think an accordian with fluid(liquid or gas) that changes density opening and closing contacts connected

Front 6

liquid bulb type device explain

Back 6

rigid metal filled with fluid liquid

there is a diaphragm at the end of an attached tube imagine a plunger

this diaphragm get pushed is as liquid is forced through the tube creating a connection

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the liquid bulb is great for

Back 7

water and air pipes!

copper is used inside to speed temp changes and read pg 5

Front 8

thermocouple what are they what do they do?

Back 8

a bimetal junction is heated creating a small voltage usually induced by heat from fire. the small voltage can operate relay coils and ****

Front 9

thermocouple voltage?

Back 9

usually 30 mV but it depends on the heat source

Front 10

thermopile?

Back 10

a few connected thermocouples in series capable of reaching 800 mV

good for operating light loads like

solenoids

Front 11

a temperature sensing device that is solid state is a semi conductor and has a negative temp coefficient

Back 11

thermistor! because resistance goes down because temp goes up hence semi conductor

Front 12

resistance temperature device?

Back 12

RTD remember that dildo thing at engie? its used because? see hint

Hint 12

high melting point of the metal and corrosion resistance makes ideal for extreme temperatures

Front 13

what can measure temps at 4000°C? using a lens

Back 13

pyrometer! they work with a lens and thermocouple

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hight limit is needed to prevent

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overheating do to blocking or **** fans

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upside down type furnaces with no basement usually use

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2 high limits

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high limit set point?

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typically 80 to 120°C

buuuuut the max is 121 and for gravity furnaces 149 wow that hooooooooot

Front 17

dip means

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dual in-line package

Front 18

dip is basically

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a bunch of bs switches that adjust temp setting organized like

off off for highest

on on for lowest and all combos of this inbetween

Front 19

fan control take place in the

Back 19

plenum

Front 20

a manual overide to the switch is called a

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summer/winter switch

Front 21

a fan control requires what considerations

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comfort proper cycling and economy

Front 22

fan on and off explain

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settings that if mismanaged will over or under heat a home

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fan on and off to narrow can cause

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cycling improperly see pg 12

Front 24

fan on suggested setting

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49-60°C

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fan off suggested

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32-38°C

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differential fan settings

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17-22°C

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high limit cycling is when the

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high limit is too low keeping the fan from doing its thing the abundance of hot air makes the system turn and and off over and over

Front 28

to keep the high limit out kf the same inclosure as the fan somtimes what is done?

Back 28

have the high limit switch a transformer

Front 29

thermostat contacts are

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1 mercury

2 spring

3 glass enclosed magnet

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thermostats for heating must break connection when?

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warm

Front 31

thermostats for cooling must break when?

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cold

Front 32

you can get heating and cooling thermostats that work like

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3way switches

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in heating cooling a what is used so you have proper delays between heating and cooling

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anticipator it heats up from current and radiation from it trips the thermostat ahead of time

Front 34

you can use a anticipator for cooling yes or no

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yes just give it a higher resistance

Front 35

a adjustable anticipator works with a

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reostat

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two stage thermostat

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first stage for warmer days produces less heat and second stage goes crazy mode for cold days this is a effiencent system

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mercury thermos must be install?

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level

Front 38

and outside wall is good for a thermstat yes no

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no heat loss from the wall is bad for proper detection

also stay away from lamps and heatsources

Front 39

where should you put a thermostat

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in natural circulation of air

Front 40

a bi metal strip element in a thermostat consists or two different metals one which

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has a high rate of thermal expansion

Front 41

a blank device would be good for large snap action contacts

Back 41

bellows

Front 42

blank bulb temp sense device

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liquid

Front 43

thermocouple purpose is to

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prove the presence of flame

Front 44

in a heating thermostat the anticipator is wired in

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series

Front 45

the cooling thermostat is wired blank with the anticipator

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parallel

Front 46

can a 120v thermostat be a temp substitute for a mV thermostat

Back 46

yes but temp varies through a wider differential

Front 47

Back 47

memorize pg 18

Front 48

disc type have

Back 48

sealed constructions

not adjustable and are inexpensive