Simmons C.H., Dennis E.M. Manual of Engineering Drawing

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220 Manual of Engineering Drawing

is returned and mixed with a supply of fresh outside

air. The mixed air will then be returned to the room

via a supply air fan after its temperature has been

corrected to suit the design requirements.

In most cases this involves a heating operation.

However, if the outside air temperature is high, or if

there are considerable heat gains within the controlled

space, then a cooling operation may well be necessary.

In addition, full air conditioning specifications require

control of the relative humidity in the space.

Personal physical comfort conditions depend on

adjusting air and surface temperatures, humidity and

air movement. By balancing these four factors, the

engineer can design a climate to suit any type of activity.

In Fig. 27.6 the air is heated by passage through a

heat exchanger supplied with hot water. Hot water

from a boiler operating at normal atmospheric pressure

is Low Temperature Hot Water (LTHW). If the boiler

operates at pressure, its output is High Temperature

Hot Water (HTHW). The heat exchanger could also be

supplied with steam or operated by electricity.

The volume of outside air supplied will vary

considerably with the occupancy density within the

space and the activity. For example, theatres, public

houses, conference rooms, areas with large solar heat

gains, industrial premises with processing equipment,

swimming pools and incubators, to name just a few,

all require very special attention. Hence, various degrees

of air purification and levels of sophistication exist.

Three typical schemes now follow and Fig. 27.7 shows

a ventilation system. Here a controller adjusts the

position of a three way valve so that more, or less,

water passes through the heat exchanger in response

to supply air temperature demands. The air supplies

are controlled by electrically operated dampers fitted

in the ducts. Note that the air into the space has its

temperature measured by the sensor f1. An alternative

position for the sensor could be in the outlet duct when

it could take note of any temperature increases generated

within the space, or it could be positioned within the

space itself, shown by u2. Many choices need to be

considered.

A scheme for partial air conditioning is illustrated

in Fig. 27.8 where in addition to ventilation and heating,

the humidity has been given a degree of control. For

full air conditioning it is necessary to provide equipment

to cool the air and typical plant has been added to the

layout in Fig. 27.9.

All of the installed plant needs to be carefully sized

to ensure that specifications for air quality are met.

The Engineer uses a psychrometric chart to determine

the physical properties of the air to be handled.

Fig. 27.2 (continued)

50HZ input at

TR1 and TR3

TR1 output

TR2 output

C4, R6, output

(Differentiator)

TR3 output

C3, R7, output

(Differentiator)

TR4 input

TR5 output

Note

. Although the waveforms shown in (c) are of assistance to the reader

in establishing that the correct signals are present at various parts of the

diagram, thus assisting preliminary fault location, it does not show the

timing relationship that exists between waveforms. This diagram is a sup-

plementary diagram that defines this time relationship.

(d) Supplementary diagram for waveform development for zerovoltage

trigger

Engineering diagrams 221

Battery

–

G1012

Earth

distribution

09.00

54–72 2.6 BK/RD

P90

Fuse/relay box

Power

distribution

07.00

C122

Light/wiper switch

(0) Off

(1) Side/tail

(2) Dipped beam

58–34 1 SR/YE

Power

distribution

07.00

58–1 1 SR/YE

C122

K20

Dim light

relay

C122

54–73A 2.5 BK/OG

C26

Earth

distribution

09.00

G1001

C26

54–96 2.5 BK/GN

F25

20k

Ignition

switch

(1) Off

(2) Radio

(3) Run

(4) Start

Power

distribution

07.00

S18

15–16 2.5 BK/SR

15–B 4 BK

15–F 4 BK

15–19 2.5 BK/YE

S18

C31

15–18 2.5 BK/OG

C31

Light/Wiper

switch

(0) Off

(1) Side/tail

(2) Dipped beam

56–1A 2.5 RD/YE

F12

18k

F23

15k

P90

Fuse/relay box

Fuse details

08.00

Fuse details

08.00

56-1 2.5 RD/YE

Multi-function

switch

(1) Flash

(2) Dip

(3) Main

C160

32.00-02

56A-3 2.5 WH

56B-16 .75 YE

C121

Dipped beam

relay

C121

Earth

distribution

09.00

G1001

32.00-02

56A-16 5 YE/BU

R18

dim light

resistor

(a) Headlamps 32.00–01 (Ford Motor Co. System).

Fig. 27.3

222 Manual of Engineering Drawing

32.00–00

32.00–01

56B-15 2.5 YE/BU

32.00–00

32.00–01

56A-3 2.5 WH

P90

Fuse/relay box

56A

58A

56B

58B

Fuse details

9.00

Fuse details

9.00

56A-2 1.5 WH/RD

Fuse details

9.00

56A-1

1.5 WH/GN

F12

10A

F12

10A

F13

10A

F14

10A

C338

Instrument

cluster

(9) Main beam

C22

C338

Earth

distribution

09.00

G1001

Earth

distribution

09.00

Earth

distribution

09.00

C22

Headlamp, right

C22

C28

Headlamp, left

C28

(b) Headlamps 32.00–02.

With tachograph

Fig. 27.3 (continued)

Engineering diagrams 223

15 18

F15

10A

Fuse details

08.00

Instrument

cluster

(4) Direction

indicator

work technograph

54–19 1 BK/RD 30–17 2.5 RD

Indicator

flasher relay

F17

10A

F19

10A

P90

Fuse/relay box

49A-1 .75 BK/WH/GN

C336

32.40-00

1.5 BK/BN

C414

49-1

C-1

.75 GN/WH

C49

C41

LHD

RHD

49A

C49

Earth

distribution

09.00

G1001

Earth

distribution

09.00

Trailer warning

light

32.40-00

1.5 BK/BN

49-1

1.5 BK/WH/GN

49A-1

C160

Headlamps

32.00

54-58 2.5 BK/SR

Headlamps

32.00

2.5 RD/YE56-1

Multi-function

switch

(0) Off

(1) Flash

(2) Dip

(3) Main

(4) Hazard

flesher

warning

light on

(5) RH direction

indicator

(6) RH direction

indicator

(7) Horn

C160

2.5 WH

56A-3

.75YE

56B-16

Headlamps

32.00

32.40-02

1BK/WH

L-3

1BK/WH

R-3

32.40-01

Horn

32.70

71 2.5 RD/YE

5k 30

18 1849A 49

‡

Fig. 27.3 (continued)

224 Manual of Engineering Drawing

54-33 1 BK 54-32 1 BK

15 30

P90

Fuse/relay box

Fuse details

08.00

C20

Windscreen

washer pump

F10

10A

53-C .75 BK/GN

Headlamp

washer

32.61

.75 BK/SR

53C-1

C31

Light/wiper

switch

(0) Off

(3) Normal

speed

(4) Fast speed

(7) Intermittent

wipe

(8) Windscreen

washer/

headlamp

washer

C31

Earth

Distribution

09.00

G1001

K11

Front

intermittent

wiper relay

C143

31B-14

1 BN/YE

54-35 .75 GN/BK

31B-5A

1 BN/

Wiper motor

C24

C2H

31B-5 1 BN/WH

53-1 1-GN

53-2 1-RD

53B

123

318

LHD

RHD

LHD

RHD

Earth

distribution

09.00

Earth

distribution

09.00

G1001

(d) Wiper/washer control 32.60–01.

F20

10A

Fig. 27.3 (continued)

Engineering diagrams 225

Fig. 27.4 Component location views 90.10–22

Component location views

ABCDEF

C123

N16

N15

C49

C162

N13

N14

C39

C105a

N26

S18

S10

S11

C68

C93

S3 C339 C8

C340

G1001 S13 S12

C71

C105b

Behind dash (LH drive shown, RH drive similar)

A2 ....... Instrument cluster ............................. D1

C2 .................................................................. E0

C3 .................................................................. D1

C6 .................................................................. D1

C7 .................................................................. E2

C8 .................................................................. C4

C9 .................................................................. D3

C39 ................................................................ A4

C49 ................................................................ E1

C68 ................................................................ B4

C71 ................................................................ E4

C93 ................................................................ C4

C123 .............................................................. D1

C162 .............................................................. E1

C339 .............................................................. C4

C340 .............................................................. D4

C105a ............................................................ A3

C105b ............................................................ F4

E4 ....... Trailer warning light .......................... E1

G1001 ............................................................ E4

M3 ...... Heater blower ................................... E2

N3 ...... Door ajar sensor, passenger side ..... F4

N13 .... Electrical headlamp alignment ..............

........... system switch ................................... E1

N14 .... Heater blower switch ........................D3

N15 .... Stop light switch ................................ D1

N16 .... Safety switch .................................... D1

N26 .... Door ajar sensor, driver side ............. A3

S1 ................................................................... B4

S2 ................................................................... B4

S3 ................................................................... C4

S4 ................................................................... D4

S5 ................................................................... C4

S6 ................................................................... B4

S7 ................................................................... B4

S8 ................................................................... B4

S10 ................................................................. B4

S11 ................................................................. B4

S12 ................................................................. E4

S13 ................................................................. E4

S18 ................................................................. B4

226 Manual of Engineering Drawing

C107

56B-4 YE/WH

58–26 SR/BU

30–66 RD/YE

31–49 BN

58–20M SR/GN

31–117 BN

C110

C111

Connector views

56B 1B YE/BK

56B–18A YE/WH

31–98B BN

56B-9 YE/SR

56B–18 YE/WH

31–98A BN

C120 C121 C122

54–54A BK/OG

30–41 RD/WH

30–40 RD/YE

31–113 BN

56B–16 YE

54–96 BK/GN+

56B–15 YE/BU

[54–99 BK/GN+

56B–15 YE/BU]

15–19 BK/YE

31–89 BN+

31–105 BN

[31–49 BN+

31–105 BN]

58–34 SR/BU

54–73 BK/OG

54–72 BK/RD

31–89 BN

C123 C126 C128

54–88 RD/PK

54–89 GN/PK

93-1 BN/BU

15–17K BK/RD

31B–26 BN/RD

31B–28 BN/YE

31B–27 BN/BU

9–8 GN/BK

92- RD

54–12 BU/GN

C129

15–17 BK/RD

9–9 GN/WH

15–17 BK/RD

54–12 BU/GN

92 RD

9–8 G–BK

Fig. 27.5 Connector view 91.00–05

Engineering diagrams 227

RAZU

V R

MIAU

Air types: (DIN 1946).

Air type Abbreviation

Outside air AU

Penetrated outside air VAU

Exhaust air FO

Aftertreated exhaust air NFO

Extract air AB

Room air RA

Aftertreated extract air NAB

Return air UM

Mixed air MI

Supply air ZU

Pretreated supply air VZU

Water:

Flow V

Return R

Fig. 27.6

°C

h kJ/kg

–10 0 10203040506070

0.8

1.0

0.6

0.4

–15 –10 –5 0 5 10 15 20 25 30 35 40

[°c]

0 2 4 6 8 1012141618

kg/kg

Fig. 27.7 Ventilation system diagram. System designed to control the temperature of supply air into a space with heating from LTHW, HTHW or a

steam heated coil. Variant with remote setpoint potentiometer

∆p

u2 u1

°C

%rH

°C

h kJ/kg

–10 0 10 2030 4050 60 70

0.8

1.0

0.6

0.4

–15 –10 –5 0 5 10 15 20 25 30 35 40

0 2 4 6 8 10 12 14 16 18

kg/kg

Controller output temperature

Controller output humidity

[°C]

–

0 V

20 V

[%rH]

–

0 V

20 V

[°C]

–

– x

[°C]

–

–x

E [22 °C]

Setpoint curve

Fig. 27.8 Partial air conditioning system. System designed to control the extract air from a room. The air into the space is heated with an electric

heating coil and humidified with steam. Alternative: Room sensor instead of extract air sensor. Variant: with low limit supply air temperature control,

and high limit supply air humidity control

0.2

228 Manual of Engineering Drawing

Functions

Temperature control

The duct sensor f1 measures the temperature t

. The

controller u1 compares this value with the selected setpoint

on the controller u1 or on the remote setpoint

potentiometer u2 and adjusts the heating coil valve s1 in

accordance with the difference between the two.

Safety devices

When there is danger of frost, the frost protection thermostat

f2 must switch off the fan, close the damper s2, open the

heating coil valve s1 and, where appropriate, switch on the

heating pump.

Controller output temperature

[%rH]

–

20V

°C

h kJ/kg

–10 0 10 20 30 4050 6070

0.8

1.0

0.6

0.4

–15 –10 –5 0 5 10 15 20 25 30 35 40

[°c]

0 24681012141618

kg/kg

°C

–

°C

%rH

0.2

°C

Functions

Temperature control

The duct sensor f1 or the room sensor f2 measures the

temperature t

. The controller u1 compares this value with

the selected setpoint X

and adjusts the heating coil step

controller (or power controller) u2 in accordance with the

difference between the two.

Humidity control

The duct sensor f1 or the room sensor f2 measures the

humidity ϕ

. The controller u3 compares this value with the

selected setpoint X

and adjusts the humidfying valve s1 in

accordance with the difference between the two.

Safety devices

If there is an air flow failure, the differential presure switch

f4 must cut off the control voltage of the electric heating

coil. With electric heating coils, it is advisable to incorporate

a timer so that the fan will run on for approximately 5 min

and dissipate any residual heat.

Fig. 27.9 Air conditioning system diagram. System designed to control the extract air from a room. The air into the space is heated by LTHW, HTHW

or a steam heated coil. Cooling and dehumidifying with CHW cooling coil. Humidifying with steam. Alternative: Room sensor instead of extract air

sensor. Variants: with low limit supply air temperature control, and with summer compensation

Engineering diagrams 229

Building management

Figure 27.8 and 27.9 show possible schemes for partial

and full air conditioning. In addition to the controls

indicated there will be all the associated ductwork,

filters, water, steam and electrical services. An electrical

control panel is usually necessary for the wiring of

interconnected equipment, instrumentation, and to

isolate plant for servicing. Although operations are

generally fully automatic, emergency hand control

facilities are often specified.

In an industrial situation where many departments

exist under the one roof, a central building management

system is necessary if the Plant Engineer requires to

know what is happening in the installation at any time.

Figure 27.10 shows a diagrammatic arrangement of

a building management system with software designed

specifically for the installation. Control is from a

standard IBM compatible PC(1), see Fig. 27.11.

The operator can check how any of the peripheral

components (4) are working. Control units for major

items of equipment such as boilers, fans, etc. are shown

as item (3). Individual room controllers (5) control

energy consumption as a function of room occupacy,

the time of day and season. System controllers (2)

coordinate process control tasks such as the overall

management of energy.

The Plant Manager has instant access to data using

a mouse operation and pull down menus. Individual

schematic diagrams can be displayed. Recorded data

over a period of time can be displayed or printed out.

The psychrometric chart (Fig. 27.13)

In air conditioning technology, it is necessary to define

thermodynamic processes and the properties of moist

air.

This may be achieved by a good knowledge of

physics, with theoretical calculations using complicated

formulae and tables. The procedure can be time

consuming.

By presenting the interrelated factors on a

psychrometric chart, an immediate decision can be

made regarding the feasibility of controlling an air

Functions

Temperature control

The duct sensor f1 or the room sensor f2 measures the

temperature t

. The controller u1 compares this value with

the selected setpoint X

and adjusts the heating coil valve

s1 or the cooling coil valve s2 in sequence in accordance

with the difference between the two.

Humidity control

The duct sensor f1 or the room sensor f2 measures the

humidity ϕ

. The controller u2 compares this value with the

selected setpoint X

and adjusts the humidfying value s3 or

the cooling valve s2 in sequence in accordance with the

difference bentween the two.

Safety devices

When there is danger of frost, the frost protection thermostat

f4 must switch off the fan, close the damper s4, open the

heating coil valve s1 and, where appropriate, switch on the

heating pump.

Variant: with low limit supply air temperature control

The low limit supply air temperature sensor f3 prevents the

supply air temperature t

from dropping below the cut-in

point X

set on the controller u1 (draught elimination).

Variant: with summer compensation.

The outside temperature compensation sensor u3 is used to

increase the room temperature t

in summer. If the outside

temperatue t

rises above the cut-in point X

(22°C), the

setpoint X

is increased continuously by the selected

steepness S

Engineer uses a psychrometric chart to determine the

physical properties of the air to be handled.

Controller output temperature

[°C]

–

0 V

20 V

Controller output humidity

[%rH]

–

0 V

20 V

[°C]

–

–x

E [22 °C]

Setpoint curve

[°C]

–

– x