Hoval CT-plus Series User manual

Revision No. 1 Issued By IJR Technical Dept
Approved KS
Dated: May 2003



By Appointment to
Her Majesty the Queen
Boiler Manufacturers & Engineers
Hoval Ltd Newark



Revision No. 2 Issued By IJR Technical Dept
Dated June 2006 Apprioved By KS

2
 

   

Hoval Ltd, Northgate, Newark, Notts NG24 1JN Tel: [phone] Fax: [phone]
e-mail: [e-mail] web site: www.hoval.co.uk
Table of Contents
3
4
5-6
7-8
9-13
14
15
16
17
18
19
20
21
These instructuctions should be read and understood before attempting to install,
commission or operate this unit.
Introduction
Description of CT-plus Calorifier
Technical and Performance Details CT-plus Calorifier
Installation and Piping Layouts
Unvented Systems
Commissioning & Operation
Inspection and Maintenance
Immersion heaters
Immersion heater wiring diagrams
Fault Finding Chart
Wiring Diagrams for Open Vented Calorifiers
Wiring Diagrams for Unvented Calorifiers
Notes

3
Introduction
Introduction
These instructions have been written to give a brief description of the CT-plus
Calorifier, itsinstallation,commissioning,operation andsubsequent maintenance.
Theinstallationofcalorifiers andtheir ancillaryequipment isnormally carriedout byan heating
engineer. For the purpose of this manual he is regarded as the installer, and, as such, it is his
responsibility to ensure that he has read and understood the contents of this manual before
installingthecalorifier.
It is essential that each calorifier has all services permanently connected to it before commis-
sioningis requested.
The installation should be in accordance with
currentI.E.E.regulations,relevantBritishStan-
dard and Codes of Practice, Building Regula-
tionsandLocal AuthorityBylaws.
Commissioning should be arranged via the
heatingengineer.Hovalengineersareavailable
to carry out this work if requested. Where the
calorifier installation is part of a Hoval boiler
package it will normally be commissioned at
the same time and entry made on the report
opposite
Commissioning/Combustion Report
Anoteshouldbeenteredbelowbythepersonresponsiblefortheplant,givingtheboiler,calorifier
modeland itsoutput andreference “K” number, asindicated onthe nameplate.
For completion by Plantroom Attendant
CalorifierModel:
Boilertype /Model:
Dateof installation:
Outputl/hr:
“K”Number:
For technical, servicing or parts enquiries,
telephone, fax or e-mail to Hoval Ltd quoting
the calorifier(s) K. number, as above

4
Description of CT-plus Calorifier

CT-plus calorifiers are designed to operate with
the full range of Hoval boilers up to 3.10 Bar pri-
mary pressure, and are intended for the produc-
tion and supply of DHW to commercial and indus-
trial premises.
The CT-plus is available in four model sizes with
high performance outputs up to 1590 litres per
hour.
General Details
The construction of the CT-plus is in the form of a
vertical, free standing unit, comprising a high grade
stainless steel inner vessel with a “rippled”wall to
enhance heat exchanger efficiency. This is sur-
rounded by a mild steel primary water jacket, which
is encased with steel sheet insulated panels. The
assembly is mounted on four legs with the primary
flow and return connections on the side. On all
four models, the secondary flow is from the top
and the smallest model (CT-plus 180) also has
the secondary return and cold feed connections
at the top. For the three larger models, all the con-
nections other than secondary flow are at the base.
Applications
Performance of the four CT-plus models covers a
range of outputs up to an hourly rating of 1590
litres/hour. Higher outputs can be provided by ar-
ranging the units in modular formation. For most
typical applications (other than process water gen-
eration) the key requirement is for adequate quan-
tities of hot water over a relatively short period. On
this basis, the CT-plus will provide significantly
higher flow rates than its continuously hourly rate.
Key Features
•Minimum floor area, fits through standard
doorway.
•Suitable for use with any make of boiler
•High efficiency heat transfer for rapid
D.H.W. regeneration.
•Recirculation design removes danger of
temperature stratification.
•Optimum D.H.W. storage - sufficient for quick
draw-off but with lower standing losses than
conventional large volume calorifiers.
•Low level connection for complete draining
and flushing out. (CIBSE TM 13:2000
Recommendations to prevent Legionella
Bacteria Contamination).
•Very low primary and secondary resistances.
•Electric immersion heaters can be fitted by
prior arrangement.
•Large heating surface, suitable for operation
with lower temperature primary feed from
condensing boilers.
•See Appendix 5 for unvented systems and
the additional equipment required.
Internal view of CT-plus Calorifier
1. Primary Inlet
2. Primary Outlet
3. Cold feed
4. Secondary Flow
5. Secondary Return
6. Drain
7. Primary air release
cock
8. High efficiency
insulation
9. Non-corrosive
stainless steel cylinder
10. Special “ripple” inner
shell to enhance
heat transfer
11. Primary water
surrounds DHW
cylinder
12. Thermostat(s)
13. Inspection and cleaning
cover
(CT-plus 280-520)
7412
13
1
2
8
10
3
9
65
11
T&P valve on unvented
calorifiers only

5
Technical and Performance Details CT-plus Calorifier
Dimensions
Model AB CD E FG HJ 1
Inlet 2345 67 Outlet Cold Feed Flow Re-
turn Drain Lifting
1555
1650
1650
2050
600
700
800
800
600
700
800
800
180
180
180
180
254
254
254
254
1030
1280
1280
1675
138
85
85
85
158
120
120
120
90
85
85
85
1” 1” 1” 1” 3/4” 1” 1.1/4”
1.1/4” 1.1/4”1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1.1/2”
1”
1”
1”
*
*
*
Position of electrical connections
to thermostat. 240v 1 phase 50Hz *Connection 4 may be used for lifting on these models. Connection 8 - Primary air release cock.
Primary Secondary
Connections - BSP Male
CT plus 180
CT plus 280
CT plus 420
CT plus 520
CT plus 180 CT plus 280 - 520
Water Content Weight
Primarylitres Secondary
litres Dry kg Wet kg
61 180 177 418
94 280 211 585
114 420 248 782
135 520 302 957
Working Pressures.
System. Max Working Pressure. Test Pressure.
Primary 3.10 bar 5.18 bar
Working Temperatures.
System. Normal Temp. Max Temp.
Primary 82 C 90 C
o
oo
o
Secondary 6.00 bar 9.00 bar
Secondary 60 C 70 C
Model
CT plus 180
CT plus 280
CT plus 420
CT plus 520
B
CB
C
JJ
G
A
H
8
6
3
5
4
7
F
E
D
1
2
1
2
4
56
83G
G
H
JJ
AF
DE
Both sides flooded.
Technical and Performance Details
Fitan anti-thermal
looptocoldfeed.
T&P valveconnection
forunvented calorifiers
(optional)
T&P valve
connectionfor
unvented
calorifiers
(optional)
Pipesizescanbeexpandedtosuit
siterequirements ifnecessary on
leavingthe calorifier.
PlanView
PlanView

6
Outputs Based on 10oC Cold Feed, 82oC Primary Flow and 60oC Secondary Flow.
Model at different primary flow rates
Hydraulic Resistance
at different flow rates
Primary Secondary
Flow rate l/s Resistance m bar Flow rate l/s Resistance m bar
CT plus 180
CT plus 420
CT plus 280
CT plus 520
Primary flow rate
litres/second
Continuous hourly
draw off litres
10 mins draw off
litres
0.75
1.12
1.50
180
1.50
2.50
720
1000 280
1.50
2.00
2.78
960
1250
1365 420
520
550
590
1.50
2.00
2.78
1037
1337
1590 520
0.75
1.12
1.50
1.50
2.50
1.50
2.00
2.78
1.50
2.00
2.78
35
78
140
15
50
15
23
63
13
23
63
0.75
1.12
1.50
1.50
2.00
1.50
2.00
2.50
1.50
2.00
2.50
30
67
120
18
32
26
45
70
40
71
111
*
For higher flow - short duration draw off. Based on use of stored capacity only.
These secondary flow rates cover typical draw off requirements. Please note that they significantly exceed the continuous hourly rate.
Rating kW = Q x S.H. x (T2 - T1 )
Q = Calorifier hourly output - Litres (kg)
T1 = Temperature cold feed - oC
T2 = Temperature DHW flow - oC
S.H. = Specific heat (4.187) - kJ/kg oC
To calculate the load on the boiler for
the calorifier primary supply.
Note for Hydraulic Testing: The primary
jacket should not be pressurised without
first filling and sealing the inner stainless
steel vessel.
An adjustable secondary thermostat has
a sensing point which ensures that the
main body of water is held uniformly,
without stratification at the required pre-
set level, normally 60oC - 65oC.
DHW Output
*
Primary and Secondary Hydraulic Resistance.
3600
Model
CT plus 180
CT plus 420
CT plus 280
CT plus 520
Legionellae The safe temperature for storage is now considered to be a minimum of 60oC to prevent the risk of
legionella bacteria contamination. For kitchen and similar duties requiring 60oC water, the supply can be direct from the
calorifier. For washing and showering duties which require a 42oC supply, mixing or blending with cold water, external to the
calorifier, is required and will increase the secondary output listed on page 5 by about 25%.
Technical and Performance Details
When temporarily operating the primary side only, the pressure should not
exceed 1 bar g and the secondary side should be vented.
Chloride
The maximum allowable chloride content of DHW cold feed water is 100mg/litre,
(or up to 200 mg/litre where optional sacrificial anodes are fitted).
!
!
!
!
!

7
7

Installation
Position the calorifiers as required, ensuring that
side and inspection opening clearances are ad-
equate. Fit unions to all pipe connections ensur-
ing that joint seals are fitted. Fit isolating valves
to all pipework.
Installation and Piping Layouts
Note: The CT-plus calorifier is fit-
ted with a separate DHW drain
tapping. The primary drain must
be fitted off the primary outlet
connection in the site pipework.
Piping layout
For the general design of water circuits refer to
current British Standards and Codes of Practice.
A simple pumped primary flow and return, ad-
equately vented, is all that is needed. Secondary
To facilitate venting during drain
down on unvented secondary
systems, ensure that a manual
vent valve is fitted in the second-
ary flow between the calorifier
and the isolating valve. On open
vented systems the vent should
be taken from the same place.
Recommended Primary Systems
Key
(1) Safety Valve recommended if not
on adjacent boiler or system.
(2) Spring loaded non-return valve.
(3) Isolating valves.
(4) Primary pump (For diagram “B”
the main circulating pump may be
used if sufficient head is available).
(5) Thermostat (linked to primary
pump to control calorifier DHW tem-
perature, for Diagram A).For diagram
B the thermostat controls the divert-
ing valve.
On Unventedsystems there is also
a limit stat fitted.
(6) Drain cock.
(7) Diverting valve (use 30 second
motor).
A B
1
AAV
2
3
4
5
3
3
6
Primary Connections from Main Headers.
Temperature control by pump.
Primary
Water
Secondary
Water
Anti-thermal
loo
p
connections are quite conventional. Connect the
calorifier(s) to the rest of the system according
to the chosen layout. Examples of both primary
and secondary systems are shown below:
1
AAV
5
4 (if Required)
3
6
Primary Connections from Main Headers.
Temperature control by diverting valve.
3
7
Primary
Water
Secondary
Water
Installation and Piping Layouts.
Installation
Position the calorifiers as required, ensuring
that side and inspection opening clearances
are adequate. Fit unions to all pipe connections
ensuring that joint seals are fitted. Fit isolating
valves to all pipework.
Installation and Piping Layouts
Note: The CT-plus calorifier is
fitted with a separate DHW drain
tapping. The primary drain must
be fitted off the primary outlet
connection in the site pipework.
Piping layout
For the general design of water circuits refer to
current British Standards and Codes of Practice.
A simple pumped primary flow and return, ad-
equately vented, is all that is needed. Secondary
To facilitate venting during drain
down on unvented secondary
systems, ensure that a manual
vent valve is fitted in the second-
ary flow between the calorifier
and the isolating valve. On open
vented systems the vent should
be taken from the same place.
Recommended Primary Systems (Open vented DHW system)
Key
(1) Safety Valve recommended if not
on adjacent boiler or system.
(2) Spring loaded non-return valve.
(3) Isolating valves.
(4) Primary pump (For diagram “B”
the main circulating pump may be
used if sufficient head is available).
(5) Thermostat (linked to primary
pump to control calorifier DHW
temperature, for Diagram A).For
diagram B the thermostat controls
the diverting valve.
(6) Drain cock.
(7) Diverting valve (use 30 second
motor).
Note:
On Unvented systems there is a high
temperature limit thermostat fitted.
The installer should wire this back
to the control valve / primary pump
and also a 2 port motorized valve.
This should be fitted on the primary
inlet, to stop the flow of primary water
entering the calorifier in the event of
a high temperature condition.
connections are quite conventional. Connect the
calorifier(s) to the rest of the system according
to the chosen layout. Examples of both primary
and secondary systems are shown below:
!!

8 Installation and Piping Layouts
8
Recommended Primary Systems Continued.
Installation and Piping Layouts
C
Key
(1) Safety Valve recommended if not
on adjacent boiler or system.
(2) Spring loaded non-return valve.
(3) Isolating valves.
(4) Primary pump (For diagram “D”
the main circulating pump may be
used if sufficient head is available).
(5) Thermostat (linked to primary
pump to control calorifier DHW tem-
perature, diagram C). For diagram
D the thermostat controls the divert-
ing valve.
On Unventedsystems there is also
a limit stat fitted.
(6) Drain cock.
(7) Diverting valve (use 30 second
motor).
D
Recommended Secondary Systems.
Key
(1) Relief valve adjacent to calorifier.
(2) Spring loaded non-return valve.
1
AAV
2
3
4
5
3
3
6
Primary Connections direct from boiler.
Temperature control by pump.
Primary
Water
Secondary
Water
Flow
Return
Boiler
Anti-thermal
loo
p
3
1
AAV
5
4 (if Required)
6
Primary Connections direct from boiler.
Temperature control by diverting valve.
3
7
Primary
Water
Secondary
Water
Return
3
Flow
Boiler
3
3
Boiler
AAV
Secondary Connections OPEN VENTED.
Primary
Water
Secondary
Water
1
2 3 3
3 3
6
Vent
Cold
Feed
Secondary
Return
3
1
4
Manual
Vent
Valve
T & P Relief Valve
Secondary Connections UNVENTED.
Primary
Water
Secondary
Water
2 3 3
33
6
Cold
Feed
Secondary
Return
3
5
Note: On CT plus 180 calorifiers the sec-
ondary return and cold feed connections
are at the top. The cold feed should be
taken to a low level thermal syphon to
avoid thermal circulation up the cold feed.
(3) Isolating valves.
(4) Open vent.
(5) Unvented system kit.
(6) Secondary drain valve.
Recommended Primary Systems Continued.
Key
(1) Safety Valve recommended if not
on adjacent boiler or system.
(2) Spring loaded non-return valve.
(3) Isolating valves.
(4) Primary pump (For diagram “D”
the main circulating pump may be
used if sufficient head is available).
(5) Thermostat (linked to primary
pump to control calorifier DHW
temperature, diagram C). For
diagram D the thermostat controls
the diverting valve.
(6) Drain cock
(7) Diverting valve (use 30 second
motor).
Recommended Secondary Systems.
Key
(1) Relief valve adjacent to calorifier.
(2) Spring loaded non-return valve. Note: On CT plus 180 calorifiers the secondary
return and cold feed connections are at the top.
The cold feed should be taken to a low level
thermal syphon to avoid thermal circulation up
the cold feed.
(3) Isolating valves.
(4) Open vent.
(5) Unvented system kit.
(6) Secondary drain valve.
8
Recommended Primary Systems Continued.
Installation and Piping Layouts
C
Key
(1) Safety Valve recommended if not
on adjacent boiler or system.
(2) Spring loaded non-return valve.
(3) Isolating valves.
(4) Primary pump (For diagram “D”
the main circulating pump may be
used if sufficient head is available).
(5) Thermostat (linked to primary
pump to control calorifier DHW tem-
perature, diagram C). For diagram
D the thermostat controls the divert-
ing valve.
On Unventedsystems there is also
a limit stat fitted.
(6) Drain cock.
(7) Diverting valve (use 30 second
motor).
D
Recommended Secondary Systems.
Key
(1) Relief valve adjacent to calorifier.
(2) Spring loaded non-return valve.
1
AAV
2
3
4
5
3
3
6
Primary Connections direct from boiler.
Temperature control by pump.
Primary
Water
Secondary
Water
Flow
Return
Boiler
Anti-thermal
loo
p
3
1
AAV
5
4 (if Required)
6
Primary Connections direct from boiler.
Temperature control by diverting valve.
3
7
Primary
Water
Secondary
Water
Return
3
Flow
Boiler
3
3
Boiler
AAV
Secondary Connections OPEN VENTED.
Primary
Water
Secondary
Water
1
2 3 3
3 3
6
Vent
Cold
Feed
Secondary
Return
3
1
4
Manual
Vent
Valve
T & P Relief Valve
Secondary Connections UNVENTED.
Primary
Water
Secondary
Water
2 3 3
33
6
Cold
Feed
Secondary
Return
3
5
Note: On CT plus 180 calorifiers the sec-
ondary return and cold feed connections
are at the top. The cold feed should be
taken to a low level thermal syphon to
avoid thermal circulation up the cold feed.
(3) Isolating valves.
(4) Open vent.
(5) Unvented system kit.
(6) Secondary drain valve.
3
5
2
Note:
On Unvented systems there is a high
temperature limit thermostat fitted.
The installer should wire this back
to the control valve / primary pump
and also a 2 port motorized valve.
This should be fitted on the primary
inlet, to stop the flow of primary water
entering the calorifier in the event of
a high temperature condition.

9
Unvented Systems

Definition
An unvented hot water system differs from conventional
open vented systems in that no vent pipe is provided
and it is connected to the mains water supply, eliminating
the need for the provision of cold water storage tanks in
the roof space. The functions, therefore, of the open
vents and cold feeds have to be performed in other
ways. There are two basic types of unvented system:
(1) Direct off the mains,
(2) Boosted water supply.
Direct off the mains
Where mains pressure is sufficient the system can be
connected straight off the mains. However, between
the cold water supply and the DHW generator (i.e. the
CT-plus calorifier) there must be an unvented system
kit fitted.
Warning: Some pressure booster
sets have an accumulator (expan-
sion vessel). This is to reduce the
amount of pump starts and should
not be confused with the system
expansion vessel.
This kit should contain a minimum of the following
items:-
•An expansion vessel should be fitted between the
non-return valve and the calorifier to take up expanded
water during heat-up.
•An expansion relief valve should be fitted in the cold
feed between the expansion vessel and the calorifier.
No means of isolating the calorifier from this valve
should be installed.
•A temperature and pressure relief valve should be
fitted directly in the calorifier as a thermal protection
to prevent the DHW reaching 100 deg C.
•A hand reset limit stat should be fitted in the calorifier
to prevent the DHW overheating.
Balanced Unvented Systems
Some systems may be fitted with blending valves or
mixers that require a balanced hot and cold water
supply. When sizing the strainer, the PRV, and check
valve care must be taken to ensure they can pass the
flow rates at the required pressure.
Hovals’ standard unvented system kits are sized to
reduced incoming pressure to 3 bar at a flow rate that
meets the peak output of the calorifier only.
As shown in the above diagram, an unvented system kit
comprises of the following components:-
•Strainer (this is optional, but good practice, to prevent
debris passing through the valves)
•Pressure regulating valve (PRV), this allows the
pressure to be reduced and controlled at a preset
pressure. A pressure gauge is supplied to indicate
system pressure.
•Double non return valve, this prevents the expanded
water back-feeding into the mains supply and
subsequently seals the system.
•An expansion vessel should be fitted between the non
return valve and the calorifier to take up expanded
water during heat-up.
•An expansion relief valve should be fitted in the cold
feed between the expansion vessel and the calorifier.
No means of isolating the calorifier from this valve
should be installed.
•A temperature and pressure relief valve should be
fitted directly in the calorifier as a thermal protection
to prevent the DHW reaching 100 deg C.
•A hand reset limit stat should be fitted in the calorifier
to prevent the DHW overheating.
Boosted water supply
Where mains water pressure is insufficient a cold
water booster set can be fitted. Normally these sets
have integral pressure controls, in the form of either
pressure transducers, pressure switches, and or
pressure regulating valves. They also have a non return
valve which prevents back-feeding. Systems where a
booster set is installed should not have a vent and as
such are unvented.
Boosted systems should have an unvented system kit
fitted down-stream from the booster set.
T & P Relief Valve.
Control & hand
reset limit stats.
Expansion relief
valve c/w tundish.
Expansion Vessel.
Check valve.
PRV.
Strainer.
Unvented System Kit.
Cold
Feed

10
Cold water booster sets tend to be sized on the
total demand of the system and subsequently
give a balanced condition.
A separate Strainer and PRV can be fitted to both
the hot and cold water services to give balanced
system pressures. Alternatively, a larger Strainer
and PRV can be installed to cope with both hot
and cold water demands.
CT plus 180 1” 1” 1” 60 litre ¾” 1” HP60-6T1
Strainer P.R.V.
Double
Check
Valve
Expansion
Vessel
Expansion
Relief
Valve &
Tundish
T & P
Relief
Valve
T & P Relief Valve.
Control & hand
reset limit stats.
Expansion relief
valve c/w tundish.
Expansion Vessel.
Check valve.
PRV.
Strainer.
Unvented System Kit.
Cold
Feed
CT plus 280 1” 1” 1” 60 litre ¾” 1” HP60-6T1
CT plus 420 1” 1” 1” 80 litre ¾” 1” HP80-6T
CT plus 520 1” 1” 1” 80 litre ¾” 1” HP80-6T
Warning: On balanced systems
with a common PRV, Strainer and
Double check valve, ensure that
the valves are sufficiently sized
to cope with both hot and cold
water demand.
Hoval Unvented System Kits
Hoval have carefully sized and selected a range
of standard unvented system kits suitable for
installation with the CT plus range of calorifiers.
The various valves and fittings should be installed
in the sequence shown on the right.
The size of the standard unvented kits are shown
in the table below.
Please note that these kits are only sized for the
cold feed going into one of the CT plus calorifiers.
Using the PRV from a standard Hoval unvented
kit to provide a balanced hot and cold water
supply may cause pressure and water flow
problems. Ensure that the PRV can cope with
the demand from both the hot and cold water
services.
Unvented Systems
1.1/2”
1.1/2”
HP60-1”
HP60-1”
HP80-1”
HP80-1”
(Supplied with unvented calorifier)
Supplied factory fitted with unvented calorifier

11
Common Unvented System Kit.
Cold
Feed
More than one calorifier can be
installed off a single common
cold feed. Each calorifier must
have it’s own T & P valve and
expansion relief valve. No
means of isolating these safety
valves from the calorifier should
be installed.
Drain Cock
By the
Installer
Strainer
Pressure
Reducing
Valve Double
Check
Valve
Expansion
Vessel
Expansion
Relief Valve
and Tundish
Expansion
Relief Valve
and Tundish
Temperature
and Pressure
Relief Valve
Temperature
and Pressure
Relief Valve
Isolating
Valve
Isolating
Valve
Shared Unvented System Kits
Feeding two or more calorifiers.
Cold
Feed
Two or more calorifiers can be
installed with individual
unvented system kits. Where the
expansion vessels have been
sized to share the total system
expansion the two feed lines can
be joined by a pipe to allow both
vessels to be used when one
calorifier is isolated.
Drain Cock
By the
Installer
Strainer
Pressure
Reducing
Valve Double
Check
Valve
Expansion
Vessel
Expansion
Relief Valve
and Tundish
Expansion
Relief Valve
and Tundish
Temperature
and Pressure
Relief Valve
Temperature
and Pressure
Relief Valve
Isolating
Valve
Isolating
Valve
Strainer
Pressure
Reducing
Valve Double
Check
Valve
Expansion
Vessel
Cold
Feed
Drain Cock
By the
Installer
Joining pipe.
Multi-calorifier Installations
Unvented Systems
Joining pipe

12
Balanced hot and cold water
services using two PRVs.
Cold
Feed
The hot and cold water supplies
can be balanced using two
separate PRVs.
Drain Cock
By the
Installer
S
tr
a
in
e
r
Pressure
Reducing
Valve Double
Check
Valve
Expansion
Vessel
Expansion
Relief Valve
and Tundish
Temperature
and Pressure
Relief Valve
Isolating
Valve
Balanced Cold Water Supply
Balanced Hot and Cold water supplies.
Unvented Systems
Unvented System with balance
d
hot and cold water services.
Cold
Feed
The hot and cold water supplies
can be balanced by utilizing the
same strainer and PRV to
control the two supply lines.
Note it may be necessary to
increase the size of these two
fittings in comparison to the non-
return valve in the calorifier cold
feed line.
Drain Cock
By the
Installer
Strainer
Pressure
Reducing
Valve Double
Check
Valve
Expansion
Vessel
Expansion
Relief Valve
and Tundish
Temperature
and Pressure
Relief Valve
Isolating
Valve
Balanced Cold Water Supply

13
Fitting the Unvented System Kit.
Fit the components as indicated. In the suggested
schematicsdetailedonpreviouspages.
Allcomponentsmust be installed inafrostfreearea.
Ensure that valves and fittings are fitted correctly to
suit the direction of flow.
SetthePressurereducing valve (PRV) to 3 bar.
Pipeoffexpansionreliefvalveviathetundishprovided
to a gulley.
Pipeexpansionvesselintocoldfeed.Fitalockshield
valveanddrainbetweenthevesselandthecoldfeed
line.Thiswillallowtheexpansionvesselgaschargeto
becheckedduringmaintenance.Thisisshownonthe
right.
Installation of the Expansion
Vessel.
Cold
Feed
Fit a lock shield valve and drain
to allow the expansion vessel to
be isolated and drained for
periodic inspection.
Drain Cock
(By the
Installer)
Strainer
Pressure
Reducing
Valve Double
Check
Valve
Expansion
Vessel
Lock Shield
Valve (By the
Installer)
Maintenance of Unvented System Kit.
Cleanoutstrainer on commissioning andannually.
Check Expansion relief valve setting annually by
twistingthe cap on top of the valve.
Checkexpansionvesselgaschargepressure,isolate
thevessel,drainoffanywaterinthevesselandtestthe
gas pressure using a tyre gauge.
Fault Finding.
Symptom PossibleCause(s) RemedialAction
(A)Reductioninwaterflow Blockageinstrainer Cleanoutstrainer.
Blockage in PRV Clean out secondary strainer in PRV.
Wrong PRVpressure setting Check PRV pressure setting alter if necessary.
(B)Dischargefromexpansion Debrisonvalveseat Twist test knob and replace if necessary.
Relief valve. Wrongincomingpressure Adjust the pressure setting on PRV.
Expansionvesseldiaphram Checkexpansionvesselgascharge.
Failure.
InsufficientExpansionvessel Check expansion vessel size.
volume.
Expansion Vessel Sizing.
Expansion Vessel Volume = System content (l) x C.o.E.
Vessel Efficiency
Vessel Efficiency = Max Pressure (Bar Abs) - Min Pressure (Bar Abs)
Max Pressure (Bar Abs)
Where: Max Pressure is final desired working pressure + 1.
Min Pressure is pressure setting on PRV + 1.
C.o.E. at 60 Deg C is approx 0.02
Unvented Systems

14
Commissioning Instructions
•Flush all swarf, filings and other debris out of
the system, preferably using a proprietary flush-
ingagent.Donot washparticles intothe calorifier,
this could cause subsequent corrosion.
•Once the secondary side is fully flooded and
sealed, fill the primary system completely and
treat the water with a good corrosion inhibitor
(e.g. Fernox). Corrosion inhibitors are not used
in secondary (tap) water.
•Ensure that all joints are water tight and all
pipework is vented.
•Checkthat all electrical connections arecom-
plete and correct.
•Ensure that the thermostat(s) are wired up and
the sensor probes are fitted in the stat pocket.
The thermostat may be wired into the boiler con-
trols to activate the pumps or a motorised valve.
The control thermostat can be adjusted to oper-
ate between 30 deg C and 80 deg C and is usu-
ally set to 60 deg C.
Pre-commissioning:
Important:Always fillthe second-
ary side of the calorifier before
the primary. Pressurising the pri-
mary when the secondary is
empty may cause the secondary
bottle to collapse.
Commissioning
(1)Light the boiler (refer to the appropriate boiler
operating instructions).
(2)Adjust the calorifierthermostatto the required
operatingtemperature.
(3) Check that the thermostat is operating cor-
rectly.
(4) Ensure that the primary pump is working or
primary primary circuit is established.
(5)Checkthatthe operatingtemperature remains
constant.
Operating Instructions
The calorifier thermostat when wired to the pri-
marycirculating pump ordivertingvalve provides
completelyautomatic control.Itis necessary only
toadjust thethermostatif theoccasiondemands.
Warning: To avoid Legionellae, en-
sure the calorifier control stat is set
at a minimum of 60 deg C.
Commissioning & Operation
Commissioning & Operation

15
Periodic Inspection
Note: Before opening the inspection
cover always ensure you have a
spare inspection cover joint.
Cleaning
The period between cleaning will depend on op-
erating temperature and hardness of water. Lo-
calconditions will serve as a guide. Normally de-
scaling will be required less often than with con-
ventionalcalorifiers.
The following procedure should be adopted:
(1) Remove calorifier top casing panel.
(2)Remove cleanoutcover forcalorifier internals.
(3) Scrape the inside surface with a non ferrous
scaper.
Note: Chemical cleaning can be carried out if re-
quired, but such work should be undertaken in
accordance with the instructions of the de-scal-
ing compound manufacturer.
We recommend chemical treatment specialist
such as Aquazur. After chemically cleaning the
DHW calorifier internal, ensure that the unit is
thorougly flushed out with clean water.
Following cleaning, replace cleanout cover us-
ing a new gasket to prevent leaks.
Inspection and Maintenance
Draining Down
(1) Ensure that both primary and secondary
pumps are switched off.
(2) Isolate the primary inlet and outlet.
(3) Fit hose to primary drain which should be in-
stalled in primary outlet and run the hose to
a gulley.
Note: The primary side of the
calorifier MUST always be
drained before the secondary.
The secondary MUST always be
filled before the primary.
Draining the calorifier down
should be done by following the
procedure below:-
When filling the calorifier
follow the above procedure
but in reverse.
The user is advised to carry out periodic inspec-
tionbetween main servicing periods and itisrec-
ommendedthat thespecialistservicing company
also carries them out.
•Inspect the calorifier casing for obvious signs
of damage, corrosion or deterioration.
•Inspect the calorifier siting for signs of crack-
ing or settling.
•Inspect all pipes and connections for obvious
damage or deterioration.
•Remove calorifier top panel and examine in-
terior for corrosion and deterioration.
Inspection and Maintenance
(4) Open primary vent valve.
(5) Open primary drain.
(6) Isolate all secondary connections.
(7) Fit hose to the secondary drain which is lo-
cated underneath the calorifier and run the hose
to a gulley.
(8) (On sealed systems) Open manual second-
ary vent valve (this should be fitted in secondary
flow between calorifier and isolating valve).
(9) Open secondary drain valve.
Model Joint Cat No.
CT plus 180 414035
CT plus 280-520 414007

16
Immersion Heaters
Immersion heaters
General
•Allworkshouldbecarriedoutbysuitablyqualified
personnel.
•Heaters must be handled with care and stored in
dry conditions.
•Adequate withdrawal space must be provided to
allowtheremoval of the heaterassembly.
•Carefully remove all protective packaging and
visually inspect unit for any transit damage.
•Allprevailingrules,regulationsandbylawsinforce
at the time and place of installation must be
observed.
•Heaters must only be immersed in the fluid they
aredesigned toheat.
•Theintroductionofalternativefluidseveninsmall
concentrations for purposes such as sterilising
maycauseseriousdamagetotheheaterandwill
invalidatethewarranty.
•AnymodificationnotcarriedoutbyHeatexLimited
or its approved agent will invalidate certification
andwarranty.
•Precautionsmustbe taken topreventdamageto
enclosureseals.
Installation
•Theheatershouldbesecurelyfixedinpositionand
all terminal connections checked for tightness
beforeenergising.
•The installed orientation of horizontally mounted
heaters must be such that any thermostats or
othertemperaturesensorsareuppermost.
•Sealinggasketsmustbeundamaged.
•The terminal box must not be used for tightening
heater into tank or vessel.
Electrical Supply Connection
•Refertowiringdiagramonpage17.
•Thecableentryorglandplateis positionedonthe
side of the terminal box.
•Before connection ensure that the supply
correspondswiththatspecifiedontheratinglabel.
•Ensure that the sizes and types of cables to be
usedaresuitablyratedfortheloadandtemperature
of the unit.
•Eachheatermustbeprotectedbyasuitablyrated
overcurrentdevice.
•Thecablesmustentertheheaterterminalboxvia
asuitablecableglandtomaintaintheIPratingand
befitted by a qualified person.
Earth Connection
Operation
•Ensure that the active sections of all the heating
elements are fully immersed in the fluid to be
heated at all times whilst energized.
•Heat is transferred by means of electric heating
elements.
•Control of the heater is facilitated by
thermostats,thermocouplesor RTDsand
referenceshouldbemadetothewiringdiagram
inside cover to ensure that these are correctly
connectedandset prior to energising the heater.
•Where a manual reset thermostat or cut-out is
installed,the terminal box coverwill have to be
removedafterisolatingtheheatertoenablea
reset to be carried out.
THESEHEATERSMUSTBEEARTHED
Anearthconnectionisprovid-
ed inside the terminal box.
Routine Maintenance
Maintenance
•Allprevailing site safety regulations shall be
adhered to at all times.
•Equipment is to be fully isolated from the
electricalsupplyandlocked off before and whilst
any work is being carried out.
3 Monthly
•Generallyinspecttheequipmentforexternal
damageorleaks.
6 Monthly
•Isolatetheelectricalsupplyandremove the
cover.
•Ensure the terminal box is clean and dry
internally.
•Ensure the electrical terminals are intact and
secure.
•Check that the heating element insulation
resistance is at least 2 mega ohms.
•Check the continuity of all elements.
•Refitcoverwithnewgasketifrequired.
•Ensure that earth continuity is maintained
betweenallexposedconductivematerialand
main site structure.
Annually
•Carry out all 3 monthly and 6 monthly checks
asabove.
•Checkfor elementfailureor lowinsulation
resistance.
•Ifheatersarebeingleftunusedforaperiod
greater than 3 months, carry out 6 monthly
maintenancebeforeenergizing.

17
Immersion heater Electrical Diagrams
Immersion heater wiring diagrams

18
Fault finding
Fault Finding Chart
Pleasecarryoutchecks asperthelist belowwhenfaultsoccur.If you cannotrectifythefault,
contact Hoval Customer Services or your installer. Telephone number and e-mail address
areshownon therearcover.
Symptom Possible Cause Action
A. Primary Water
Circuit Inefficient (1) Leakage in system.
(2)Pumpfaultyor inoperative.
(3)Boilerfaultyor inoperative.
(4)Circuitnotproperlyvented.
(5) Pump not of sufficient duty.
(1) Check pipe connection. Renew
ifrequired.
(2) Refer to appropriate pump part
document.
(3) Refer to appropriate boiler part
document.
(4) Vent primary system.
(5)Changepumpspeedorpump.
Symptom Possible Cause Action
A. Secondary water
temperature not as
settingon thermostat.
(1) Leakage in system.
(2)Pumpfaultyor inoperative.
(3)Thermostatfaulty.
(4)Electricalfault in control system.
(5)Calorifierscaledup.
(6)Calorifiernotlargeenoughforload
imposed.
(7)Lowprimary temperature.
(8)Diverting valvebypassing.
(1) Check pipe connection. Renew
ifrequired.
(2) Refer to appropriate pump part
document.
(3)Checkandreplaceifrequired.
(4)Referto appropriate control sys-
tempart document.
(5) Mechanically / chemically de-
scale as necessary.
(6)Changecalorifieroraddcalorifi-
er/buffervessel.
(7) Turn up boiler thermostats / in-
creaseprimaryflowrate.
(8) Check primary pipe cools when
hot.Waternotrequired.

19
Electrical Diagrams
Wiring Diagrams for Open Vented Calorifiers

20
Electrical Diagrams
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