Full Text Searchable PDF User Manual
November 2007
Clyde CG
Wall hung condensing boilers
Natural Gas
60 kW
to
180 kW
LP Gas
60 kW
to
120 kW
Engineering Data Sheet 769/4
Contents Page
General information
2 & 3
Dimensions and Data
4
Installation requirements 5 & 6
Boiler wiring diagram
7 & 8
Flue systems
9 to 11
Hydraulic systems
12 to 14
General information
Operating principles
The CG is a wall-mounted condensing boiler with stainless steel counter flow twin heat exchangers (the CG 60 has a
single heat exchanger), pre-mix gas burner and integral flue products fan (refer Figs 1 and 2). When operating in
condensing mode with a flow of 50
°
C and a return of 30
°
C, it will give efficiencies of up to 109.5% (ncv). Gas is supplied
through a zero governor valve (2). The air intake fan (4) and venturi (3) accurately control the volumes of gas and air and
mix them prior to ignition. A small flame is held on the entire surface of the burner combustion head (6). This ensures
that there is optimum combustion at any point in the modulation range of the boiler.
System return water is passed through a number of tubes in the secondary (condensing) heat exchanger, and then the
primary heat exchanger. An integral boiler circulation pump (11) ensures an even and constant flow through the heat
exchanger - refer page 8. System circulating pumps should be hydraulically separated from the boiler(s) by a low
velocity header.
Key to Figs 1 & 2
1
Gas supply
2
Gas valve
3
Gas and air mixing by venturi
4
Fan unit
5
Ignition and flame ionisation electrodes
6
Burner head
7
First heat exchanger
8
Baffle plate
9
Second (condensing) heat exchanger
10
Flue gas outlet
11 Boiler circulation pump
12
Sound insulation panels
13
Electrical connection strip
14
Control display
Fig 1 Diagram of operating principles
Fig 2 Cut-away CG boiler
1
2
3
4
5
6
7
9
10
8
11
12
13
14
EDS769/4 page2
General information
Handling
Offloading, dry storing and placing of equipment in the
boiler room is the responsibility of the installer.
Equipment must be dry stored and protected from frost.
Cartons must not be crushed or otherwise damaged.
Commissioning
Clyde undertake commissioning of boilers. Commissioning
charges do not include servicing during the guarantee
period, although this may be carried out under service
contract or to specific order. Boilers should be
commissioned in line with CIBSE Commissioning Code B.
Servicing
The importance of regular maintenance cannot be over-
emphasised if maximum efficiency is to be maintained.
Customers are strongly advised to place the equipment
under service contract immediately commissioning is
complete.
Application
CG boilers are manufactured and tested in accordance with the Gas Appliances Directive 90/396/EEC, the Boiler
Efficiency Directive 92/42/EEC, EN 483 and EN 677 and CE marked accordingly. They are suitable for use in LTHW
heating systems with a maximum operating pressure of 6.0 bar and a maximum working temperature of 90°C (see
Technical data).
CG 60, 80, 100 and 120 boilers are suitable for use with Natural gas (G20), Propane (G31) and Butane/Propane mix
(G30). CG 150 and 180 boilers are only suitable for use with Natural gas (G20).
The boiler is suitable for use in pressurised (sealed) or open vented heating systems with a minimum static head of 0.5
bar. It is not suitable for use as a direct water heater. Where potable water is required, a matching calorifier or plate heat
exchanger must be provided in the system. All models in the range are suitable for use with a concentric balanced flue.
Statutory requirements
The installation and commissioning of the boiler must be carried out by a qualified engineer in accordance with the
instructions provided.
Gas supplies and gas burners must be installed, serviced and commissioned by a qualified person, eg. a Gas Safe
registered engineer.
Guarantee
Subject to correct handling, installation and operation, all
equipment is guaranteed for twelve months from the date
of despatch. Boiler heat exchangers are guaranteed for a
period of two years from the date of manufacture.
The guarantee is not valid if the boiler is not installed in
accordance with these instructions (please refer to page
5), becomes blocked with debris and/or carbonate
deposits from the system water and/or there is no
documented evidence of commissioning by Clyde or their
appointed engineer.
Boiler Log book
A boiler log book that provides a permanent record of
commissioning and servicing data and measurements is
supplied with every boiler. It is recommended that the
owner ensures that this log book is kept safe and brought
up to date on every occasion that routine or emergency
work is carried out on the boiler.
Emitter sizing (radiators)
The boiler will operate in condensing mode whenever the
return water is below 50°C and will reach its full potential if
the flow water temperature is also below 50°C. However,
the latter condition will mainly occur when the boiler is
heating an underfloor heating scheme or transiently when
recharging a DHW storage tank from cold. By careful
design of a traditional heating system with radiators, and
with weather compensating control in operation, the return
water temperature can be held below 50°C for most of the
heating season, only rising above this figure when outdoor
temperatures are below zero.
For optimum performance, calculate heat losses on the
basis of a 20°C internal temperature and a -8°C outdoor air
temperature. With no added factors, size the radiators on
the basis of published EN 442 data ( T50) and size the
system pump for a 10°C temperature drop. In most cases
this will ensure that the boiler begins to operate in
condensing mode when the outdoor air temperature rises
above 1°C and becomes fully condensing when the
temperature is above 5°C. For heating schemes in
buildings where the occupants have special needs,
different environmental conditions may apply and further
advice must be sought.
N
o
n
-c
o
n
d
e
n
s
in
g
0
10
15
20
5
-5
-8
Outdoor air temperature °C
20
30
40
50
60
70
80
C
o
n
d
e
n
s
in
g
°C
Bo
ile
r
°C
Re
turn
w
ate
r te
m
pe
ra
ture
°C
Fl
ow
w
ate
r te
m
pe
ra
tu
re
°C
EDS769/4 page3
Dimensions and Technical data
EDS769/4 page4
Side
Plan
90
115
202
110
106
87
458
236
L
CA
AA
306
Below
A1
307
242
385
72
HO
HI
GI
Co
H
HO
GI
Co HI
Dim e nsions
Bo ile r m o d e l / o u tp u t
kW
6 0
8 0
1 0 0
1 2 0
1 5 0
1 8 0
Bo ile r flo w co n n e ctio n
H O
R 1 ½
R 1 ½
R 1 ½
R 1 ½
N W5 0
N W5 0
Bo ile r re tu rn co n n e ctio n
H I
R 1 ½
R 1 ½
R 1 ½
R 1 ½
N W5 0
N W5 0
C o n d e n s a te o u tle t
C o
m m
Ga s In le t
GI
R ¾
R ¾
R ¾
R ¾
R 1
R 1
Flu e co n n e ctio n
AA
m m
8 0
1 0 0
1 0 0
1 3 0
1 3 0
1 3 0
C o m b u s tio n a ir in le t
C A
m m
8 0
1 0 0
1 0 0
1 3 0
1 3 0
1 3 0
Bo ile r d e p th
L
m m
4 8 5
4 8 5
4 8 5
4 8 5
6 7 0
6 7 0
Bo ile r h e ig h t
H
m m
8 3 5
8 3 5
8 3 5
8 3 5
8 9 0
8 9 0
Po s itio n o f H O
A1
m m
7 2
7 2
7 2
7 2
1 2 2
1 2 2
Te chnica l da ta
Flow 5 0 °C / Re turn 3 0 °C
H e a t o u tp u t (n cv)
Ma x
kW
5 8
7 7
9 6
1 1 6
1 5 0
1 8 0
H e a t in p u t (n cv)
Ma x
kW
5 5 .6
7 4 .3
9 2 .2
1 1 1 .2
1 3 8 .8
1 6 6
Efficie n cy (n cv)
%
1 0 9
1 0 9 .5
1 0 9 .5
1 0 9 .5
1 0 9 .5
1 0 9 .5
Flow 8 0 °C / Re turn 6 0 °C
H e a t o u tp u t (n cv)
Ma x
kW
5 5
7 3
9 0
1 0 9
1 3 6
1 6 3
H e a t in p u t (n cv)
Ma x
kW
5 5 .6
7 4 .3
9 2 .2
1 1 1 .2
1 3 8 .8
1 6 6
Efficie n cy (n cv)
%
9 7
9 8
9 8
9 8
9 8
9 8
Flu e g a s te m p e ra tu re a t fu ll lo a d
°C
Flu e g a s m a s s flo w
kg /s
0 .0 2 8
0 .0 3 8
0 .0 4 6
0 .0 5 6
0 .0 6 9
0 .0 8 4
C O
2
in flu e g a s (1 )
%
C O in flu e g a s
Ma x
m g /kWh
PH o f co n d e n s a te p ro d u ce d
N a tu ra l g a s co n s u m p tio n (g ro s s cv) (2 )
m ³/h
5 .7 4
7 .6 6
9 .5
1 1 .5
1 4 .3
1 7 .1
N 0 x Em is s io n s
m g /kWh
Bo ile r s e a s o n a l e fficie n cy (3 )
%
9 5
9 5
9 5
9 5
9 5
9 5
D ry w e ig h t
kg
4 6
7 3
7 8
8 3
9 2
1 0 1
Wa te r vo lu m e
l
3 .9
5
6 .5
8 .3
1 0 .4
1 2 .9
Ma xim u m a llo w a b le te m p e ra tu re
°C
Ma xim u m h yd ra u lic w o rkin g p re s s u re
b a r
C E R e g is tra tio n n u m b e r
Ma x e le ctrica l p o w e r co n s u m p tio n
W
3 5 5
3 5 5
3 5 5
3 7 5
4 6 0
4 6 0
Ele ctrica l p ro te ctio n
N o te s : (1 ) Me a s u re d a t th e flu e g a s a d a p to r (2 ) Ba s e d o n GC V 3 8 .7 6 MJ/m ³
(3 ) C a lcu la te d fro m th e n o n -d o m e s tic h e a tin g a n d co o lin g co m p lia n ce g u id e fo r co n fo rm a n ce w ith AD L 2 A a n d
AD L 2 B 2 0 0 6 u s in g th e fo rm u la
s e a s ona l = 0 .8 1
30%
+ 0 .1 9
100%
W a te r flow ra te s a nd hydra ulic re sista nce s
Wa te r flo w ra te a t 2 0 °C te m p . ris e
l/s
0 .7 1
0 .9 5
1 .1 9
1 .4 3
1 .7 9
2 .1 4
H yd ra u lic re s is ta n ce a t 2 0 °C te m p . ris e
kPa
2 2 .4
4 5 .8
3 8 .2
3 5 .6
4 4 .8
3 3 .6
6
C E 0 0 6 3 BP3 2 5 4
IP4 0
1 5
9 0
2 5
9
4 to 5 .5
2 0
8 5
Installation requirements
Regulations governing installation
CG boilers should be installed in accordance with all
prevailing regulations and codes of practice, including the
Building Regulations, Health and Safety Regulations PM5,
Water Bylaws and the current Gas Safety (Installation and
Use) Regulations. Detailed relevant guidance will also be
found in;
BS 6644 :2005
Installation of appliances exceeding 70
kW net input
BS 5440-2
Ventilation for appliances not exceeding
70 kW net input
BS 6891
Low pressure gas installation pipework
of up to 28mm (R1)
BS 5449
Forced circulation hot water central
heating systems for domestic premises
BS 6880
Code of practice for installation of low
temperature hot water heating systems
of output exceeding 45 kW
CIBSE Guides B and C and Commissioning Code B
Institution of Gas Engineers Utilization Procedures 1, 1A,
2, 4, 7 and 10.
Water treatment
CG boilers have a stainless steel heat exchanger and
care must be exercised to ensure that the system water
and any water treatment is compatible.
Whenever a new boiler is connected to an existing
system, the pipework must be thoroughly cleaned and
flushed. This is to remove debris, rust particles, carbonate
deposits and any existing water treatment that might be
incompatible with the heat exchanger. New systems must
also be thoroughly flushed to remove debris and flux
deposits. Clyde recommend that a permanent means of
filtration be fitted into the return pipework, such as a
sludge trap, hydrocyclone or full flow duplex filters. The
boiler guarantee will be invalid if waterways are blocked
by debris or carbonate deposits.
The pH value of the system water should be measured to
ensure that it is between 5 and 10.5. If system water is in
contact with aluminium, the pH value must be less than
8.5. Temporary hardness (calcium carbonate and
magnesium carbonate) can be removed by boiling and its
effects limited by preventing ingress of fresh, untreated
water. Permanent hardness (eg sulphates and chlorides)
must not exceed 50 mg/litre. The boiler guarantee will be
invalidated by the use of incorrect or incompatible water
treatment. Specialist advice should be obtained, eg from;
Fernox
Tel. 01483 793200
For full information on cleaning, flushing and protecting
hot water systems, refer to BSRIA Application Guide AG
1/2001.
Deaeration
It is a condition of warranty that there is effective air
separation and removal from the system. The air
separator should be fitted at the hottest part of the system.
Boiler condensate
CG boilers have a 25mm flexible condensate drain that is
compatible with standard plastic waste pipe. Do not use
other materials, as they will corrode. The pipe size must
not be reduced and there must be a continuous fall to
drain. As a further precaution against freezing,
condensate pipes should be run internally whenever
possible and lagged when run externally.
Pressurisation of systems
CG boilers should be installed as part of a pressurised
(sealed) or open vented system with a minimum pressure
of 0.5 bar. The maximum allowable pressure for the
boilers is 6 bar. They are not to be used with a gravity
system.
Boiler location
CG boilers must not be installed external to a building.
The boiler must be mounted on a sound internal wall,
capable of supporting its weight. The boiler location must
be frost-free and adequately ventilated (see below).
Contamination of the combustion air by inflammable
vapours, high dust levels or halogenated hydrocarbons
will constitute a safety hazard and will damage the boiler.
The following minimum clearances around the boiler
should be observed;
Front
500 mm
Sides
20 mm
Below
100 mm
Above 300 mm (subject to flue installation requirements)
Air supply and ventilation
Adequate air for combustion and ventilation is essential to
the safe operation of a boiler. If the boiler is installed with
a Type C balanced flue, BS 6644:2005 calls for minimum
ventilation of 2 cm
2
free area per kW net input at both high
and low level unless the ambient temperature of the plant
room ceiling exceeds 40°C.
For a single 60 kW boiler with a Type B powered flue, the
ventilation requirements of BS 5440-2 apply, and they are
partly summarised in Table 1. For ventilation direct to
outside air, the requirement is for 5 cm² per kW net rated
heat input above 7 kW.
Table 1 Ventilation for single boiler installations complying
with BS 5440-2
When the installation comprises multiple boilers or single
boilers above 70 kW net input with Type B flues, the
ventilation requirements of either BS 6644:2005 or
IGEM/UP/10 must be met. Table 2 shows the
requirements of BS 6644:2005. This standard requires
natural ventilation at both high and low levels to the
outside air, and is based on the net input of the boilers.
Appliance
Ventilation direct to outside air
CG 60
248 cm²
Ventilation direct to
outside air
Total kW input (net)
Low level
4 cm² per kW of total rated net
input
High level
2 cm² per kW of total rated net
input
Table 2 Ventilation for multiple boiler installations in a boiler
room complying with BS 6644:2005
EDS769/4 page5
Installation requirements
D
>(5
x
D
)
D
Fl
o
w
ra
te
=
0
.5
m
/s
(m
a
x
)
Fill point and
expansion vessel
System
drain
Sensor
Air
vent
Primary
flow
Primary
return
System
flow
System
return
Heat exchanger hydraulic resistance
The CG boiler has a high resistance heat exchanger. A Grundfos or DAB pump is supplied as an integral part of the
boiler to overcome this resistance and ensure a constant water flow through the boiler. This is not a system circulating
pump. The boilers are designed to work at T 20K or higher (refer Technical data on page 4). When operating at full
load at T 20, the CG60 has a pump head of 3m available for system circulation, but there is no significant pump head
available for the other models. At a higher T (eg T 25K), there is some available head with all models, and reference
should be made to the charts in the Installation Instructions. If operation at a reduced load is acceptable, there may be
adequate head for a small heating circuit or DHW calorifier.
Although there may be adequate head for primary circulation through a DHW calorifier, in all cases additional circulating
pump(s) will be required for the heating distribution. These should be hydraulically separated from the boiler(s) by a low
velocity header - see below.
Low velocity headers
Low velocity headers are used to separate hydraulically the boilers from the rest of the system. They should be used
whenever a circulating pump is installed in addition to the boiler pump. Used in conjunction with a system filter and air
separator (refer page 5), they are invaluable when connecting a new boiler to an existing system.
Low velocity headers should always be vertical and sized for a maximum water velocity of 0.5 m/s. Fig 3 proposes
dimensions for the design of a low velocity header, and Table 3 sizes dimension D for a T 20 system.
Boiler Output
(kW)
T 20
60
50 mm
80 / 100 / 120
65 mm
150 / 160 / 180 / 200
80 mm
240
90 mm
300
100 mm
360
125 mm
Fig 3 Dimensions for design of low velocity header
Table 3 Sizing guide for low velocity header
Data taken from CIBSE Guide C4 2000
EDS769/4 page6
Boiler wiring diagram
For strip connector details, refer to Fig 4 on page 8
EDS769/4 page7
Boiler wiring diagram
Note
Remote indication
LO = Lock out lamp connection
D = Demand (run) lamp connection
When driving external controls directly from the Furimat 914 controller without using a relay, the following maximum
loads must not be exceeded;
Models CG 60 to 120 = 1.45A, 230V
Models CG 150 and 180 = 1.1A, 230V
*All circulating pumps should be connected via a relay, not directly
EDS769/4 page8
Fig 4 Termination of external control components to the strip connector
O
u
ts
id
e
a
ir
s
e
n
s
o
r
0
-
1
0
V
c
o
n
n
e
c
ti
o
n
C
a
s
c
a
d
e
c
o
n
n
e
c
ti
o
n
D
H
W
d
iv
e
rt
in
g
v
a
lv
e
o
r
lo
a
d
in
g
p
u
m
p
*
(1
7
-
1
9
)
M
a
in
s
2
3
0
Va
c
R
e
m
o
te
i
n
d
ic
a
ti
o
n
PR
T
fo
r
in
d
e
x
h
e
a
ti
n
g
c
irc
u
it
C
o
m
m
o
n
f
lo
w
s
e
n
s
o
r
fo
r
L
VH
D
H
W
t
e
m
p
e
ra
tu
re
s
e
n
s
o
r
1
2
3
4
5
6
7
8
9
10
11 12 13 14
15 16 17 18 19 20 21 22 23 24 25 26
N
L
230 Vac
+
-
D
Fit link if not using PRT
+
-
LO
C
L1
N
L2
L
N
Flue systems
General
CG boilers can be supplied with a range of purpose made
stainless steel and plastic flue systems.
Standard items available from Clyde are;
Type C concentric balanced flue for horizontal termination.
Type C concentric flue for vertical termination through a
flat or pitched roof.
Also available to special order are;
Type C twin tube flue for horizontal or vertical termination.
Type B powered flue for vertical termination (ie
combustion air is taken from within the boiler room, so
ventilation must comply with either BS 5440-2:,
BS 6644:2005 or IGEM/UP/10 as appropriate - refer page
5).
Type B powered flue common headers for multiple boilers
- contact Clyde for information on these.
Type C concentric flues
The standard horizontal and vertical flue kits are
80/125 mm for the CG 60 and 80 and 100/150 mm for the
CG 100, 120, 150 and 180 models - refer Figs 5 and 6.
Additional straight lengths of 1m and 2m, plus 45° and 90°
bends are available to complete the system. All additional
lengths and fittings are supplied with the necessary
sealing collars. The straight lengths can be cut with a
hacksaw at the plain end.
A separate condensate drain tee should be installed for
long horizontal or vertical flue runs. For this reason,
horizontal flues should have a slight fall (3°) back to the
boiler.
The 80/125 concentric flue is adequate for short runs and
ideal for horizontal termination through an adjacent wall.
However, the smaller size increases the resistance of the
flue and longer runs may require 100/150 concentric flue
or twin pipe.
The EL (Equivalent Length) pressure drop of the straight
flue lengths, fittings and terminals must not exceed
250Pa for the CG60 to 120 models or 350 Pa for the
CG150 and 180. Table 4 gives the resistances of flue
components.
Fig 5 80/125 and 100/150 concentric horizontal flue arrangement
Fig 6 80/125 and 100/150 concentric vertical flue arrangement
Key to Figs 5 and 6
A
Flue gas sampling point
B
Interior wall cover plate
C
Exterior wall cover plate
Notes;
(1) Dimensions for 80/125 concentric flue
(2) Dimensions for 100/150 concentric flue
260 (1)
745 (1)
1215 (2)
B
C
A
280 (2)
1240 (1)
1350 (2)
A
EDS769/4 page9
Flue systems
Flue component
Resistance
(Pa) CG60
Resistance
(Pa) CG80
Resistance
(Pa) CG100
Resistance
(Pa) CG120
Resistance
(Pa) CG150
Resistance
(Pa) CG180
80/125 concentric wall terminal
20
27
N/R
N/R
N/R
N/R
100/150 concentric wall terminal
N/R
6
10
18
40
66
80/125 concentric roof terminal
25
32
N/R
N/R
N/R
N/R
100/150 concentric roof terminal
N/R
8
14
25
43
77
80/125 concentric pipe (per m)
14
18
N/R
N/R
N/R
N/R
100/150 concentric pipe (per m)
2.5
4.5
7
12
26
44
80/125 concentric 45° bend
8.5
11.5
N/R
N/R
N/R
N/R
100/150 concentric 45° bend
2.5
4.5
5
12
26
44
80/125 concentric 90° bend
14
18
N/R
N/R
N/R
N/R
100/150 concentric 90° bend
5
4
7
12
26
44
80 mm flue gas duct (per m)
5
8
13
N/R
N/R
N/R
100 mm flue gas duct (per m)
2
3.5
4
6.5
N/R
N/R
130 mm flue gas duct (per m)
0.45
0.8
1.2
1.8
3.8
6
150 mm flue gas duct (per m)
N/R
N/R
0.5
0.8
1.7
3
80 mm flue gas 45° bend
2.5
4
6.5
N/R
N/R
N/R
100 mm flue gas 45° bend
1
1.7
2
3.2
N/R
N/R
130 mm flue gas 45° bend
0.2
0.4
0.6
0.8
1.9
3
150 mm flue gas 45
o
bend
N/R
N/R
0.2
0.4
0.8
1.5
80 mm flue gas 90° bend
5
8
13
N/R
N/R
N/R
100 mm flue gas 90° bend
2
3.5
4
6.5
N/R
N/R
130 mm flue gas 90° bend
0.4
0.8
1.2
1.8
3.8
6
150 mm flue gas 90
o
bend
N/R
N/R
0.5
0.7
1.7
3
80 mm air supply duct (per m)
4
7.5
10
N/R
N/R
N/R
100 mm air supply duct (per m)
1.2
3
3.5
4
N/R
N/R
130 mm air supply duct (per m)
0.35
0.75
0.8
1.1
1.2
2
150 mm air supply duct (per m)
N/R
N/R
0.3
0.4
0.6
1.2
80 mm air supply 45° bend
2
3.5
5
N/R
N/R
N/R
100 mm air supply 45° bend
0.6
1.5
1.7
2
2.2
N/R
130 mm air supply 45° bend
0.2
0.4
0.4
0.5
0.6
1
150 mm air supply 45
o
bend
N/R
N/R
0.15
0.2
0.3
0.6
80 mm air supply 90° bend
4
7
10
N/R
N/R
N/R
100 mm air supply 90° bend
1.2
3
3.5
4
10
9
130 mm air supply 90° bend
0.3
0.7
0.8
1.1
1.2
2
150 mm air supply 90
o
bend
N/R
N/R
0.3
0.4
0.6
1.2
Table 4 flue gas component resistances
EDS769/4 page10
Flue systems
A
A
G
M
E
C
B
G
D
J
F
H , I
F
F
K
K
L
L
Fig 7 Location of concentric balanced flue terminals
Key to Fig 7
A
Directly below an opening
300 mm
B
Below gutters, soil pipes or drain pipes
75 mm
C
Below soffit / eaves
200 mm
D
Below balconies or car port roof
200 mm
E
From a vertical soil pipe or drain pipe
75 mm
F
From an internal or external corner
300 mm
G
Above ground, roof or balcony level
300 mm
H
From a surface facing the terminal
600 mm
I
From a terminal facing the terminal
1200 mm
J
From an opening in the car port
1200 mm
K
Vertically from a terminal on the same wall
1500 mm
L *
Horizontally from a terminal on the same wall
300 mm
M
Horizontally from an opening
300 mm
For further information, refer to BS 5440-2
* BS 5440-2 is concerned with boilers with a net input of up to 70 kW
(ie CG 60). IGEM UP/10 gives guidance for boilers of greater out put.
To conform with this Utilisation Procedure, dimension L should be
increased to 600 mm.
Where boilers with a total output of 150 kW or more are to have
horizontal terminals on the same wall, reference should be made to the
Clean Air Act to determine whether dispensation should be sought.
EDS769/4 page11
Hydraulic system design and control
General
The Furimat 914 controller built into each boiler can provide cascade control of up to eight boilers without the need for
external controls. A 230 Vac permanent supply must be provided for each boiler. One boiler is designated as the
master, and the others connected in series by a two wire bus (RS 485 serial communication system). A full weather
compensation program is included in the Furimat 914, and this is activated by connecting an Outside Air Sensor to the
master controller. A time clock or programmable room thermostat (PRT) can also be connected to the master, or an
open therm modulating controller (RC).
Individual heating circuits can be controlled by the inclusion of EBC controllers. Each EBC can control 2 heating circuits
via 2 no. 3-port mixing valves and 2 no. circulating pumps. Up to 2 EBC units can be fitted in each boiler, giving a
maximum of 32 heating zones with 8 boilers. Additional EBC units can be wall-mounted if more than 4 heating circuits x
the number of boilers are required. Additionally, a modulating zone controller (RCO) is required for local control of each
heating circuit. Note that the maximum electrical current that can be switched by each EBC is 2A, so additional relays
(not supplied by Clyde) may be needed.
The arrangement shown in Fig 8 will heat a single heating circuit, directly compensated on the common boiler flow
temperature. A second heating circuit can be controlled by a 3-port mixing valve, connected to the master boiler.
However, the flow temperature of this secondary circuit cannot exceed the compensated flow temperature of the index
circuit. Alternatively, an EBC contoller can be incorporated. The boilers should be hydraulically separated from the
system by a Low Velocity Header (LVH). Although the boilers each have a circulating pump, there is no facility to control
additional circulating pumps from the Furimat 914 other than via an EBC.
DHW calorifiers can be connected either side of the LVH, controlled from the master boiler or EBC by an immersion
sensor and either a loading pump or 3-port diverting valve.
0 - 10 Volt connections are also provided with the Furimat 914.
If plastic pipework is used in the heating system (either proprietary push-fit for conventional radiator circuits or underfloor
heating), this must be hydraulically separated from the boiler eg by a plate heat exchanger. This is to prevent magnetite
fouling the boiler heat exchanger and is particularly important if the plastic pipework does not have an oxygen barrier.
Key to figs 8 to 10
Items supplied as part of optional controls packs
EBC
Boiler-mounted controller
FA
Outside Air Sensor
FB
DHW calorifier sensor
FK
Common flow temperature sensor
FV
Flow temperature sensor
PRT
Programmable Room Thermostat / Timeclock
RC
Modulating Room Controller
RCO
Local heating circuit controller
CGCPU Pressurisation unit
Items not supplied as standard by Clyde;
AS
Air Separator
DV
3-port diverting or control valve valve
EV
Expansion vessel
F
Filter
KR
Non-return valve
PH
Heating circuit pump
PS
DHW primary pump
SH
Mixing valve
EDS769/4 page12
Hydraulic system design and control
Fig 9 Single boiler with up to 4 heating zones
This arrangement has a secondary heating circuit and mixing valve, with a maximum flow temperature that cannot exceed the
compensated flow temperature of the index circuit. The DHW calorifier is still controlled from the boiler via the 3-port diverting valve
(DV) and DHW sensor (FB).
FA
RC
EV
DV
FB
F
Master
FK
PH1
SH
PH2
PH3
SH
PH4
SH
EBC
EBC
RCO
RCO
RCO
Fig 8 Single boiler with one heating zone and optional DHW calorifier connected to the “High” temperature side of the LVH
The DHW calorifier is directly controlled from the boiler via the 3-port diverting valve (DV) and DHW sensor (FB). The PRT or RC
(Programmable Room Thermostat/ modulating control) gives time control of the heating circuit (the RC also gives time control of the
DHW). The addition of the Outside Air Sensor (FA) will provide direct weather compensation of the boiler flow temperature.
An optional differential pressure bypass valve has been included to guarantee a minimum flow through the boiler.
FA
PRT or RC
EV
DV
FB
F
PH KR
Master
AS
AS
EDS769/4 page13
Fig 10 Up to 8 boilers in cascade with optional DHW on “Low”temperature side of LVH.
The DHW calorifier is directly controlled by the master boiler via the sensor (FB) and loading pump (PS). The boilers are connected
together by a cascade bus.
F
EV
Slave 1
FK
PH1
FB
FA
RC
EV
Master
PS
Hydraulic system design and control
AS
EDS769/4 page14
Unit 10 Lion Park Avenue
Chessington
Surrey KT9 1ST
t :
020 8391 2020
f :
020 8397 4598
e :
info@clyde-nrg.com
w :
www.clyde-nrg.com
EDS 769/4
November 2007
Clyde Energy Solutions Ltd
This publication is issued subject to alteration or withdrawal without notice. The illustrations and specifications are not binding in
detail. All offers and sales are subject to the Company's current terms and conditions of sale, a copy of which is available on request.