Welcome!
1
HTU11C
Biomass Appliance Selection,
Installation, Commissioning &
Decommissioning
2
MCS ;
Microgeneration Certification Scheme
For information:
• MCS publish technology specific guidance documents
based on European standards already in existence.
• These standards have been approved for installers and
manufacturers for the installation or product approval
of Biomass, Heat Pumps, PV and Solar Thermal.
• These documents are referred to through our biomass
training units and accompanying slide shows. The
biomass standard particular to the HETAS H005DE
course is the MIS 3004.
• Register with HETAS for MCS installer business
accreditation.
3
Components of a Biomass Appliance (p3)
• Air Supply (suction)
Fan The boiler or suction fan may be used in log burning
appliances and pellet and chip burning appliances. The
purpose of this component is to maintain sufficient air
supply to support the combustion process.
• Ash Removal System (manual)
A manual ash removal system is typically used in batch
fed log appliances to enable clearance of the ash that is
generated through the combustion process.
4
Components of a Biomass Appliance (p3)
• Ash Removal System (automatic)
An automatic ash removal system may be used in chip or pellet
appliances to automatically clear the coarse combustion ash and
any loosened fly ash from the appliance grate area. An
automatic ash removal system will typically comprise of a motor
operated ash removal auger and an ash collection/storage bin.
5
Components of a Biomass Appliance
• Automatic Heat Exchanger/ Flue Cleaning Mechanism An
automatic heat exchanger/flue cleaning mechanism may be
used in pellet and chip appliances to ensure that the heat
exchanger and heat exchanger passages are kept free of fly
ash and other combustion related deposits.
6
Components of a Biomass Appliance
• In some types of biomass appliance the heat exchanger is
automatically cleaned pneumatically by means of an intensive
compressed air shock.
7
Components of a Biomass Appliance
• Manual Heat Exchanger Cleaning Mechanism
Some appliances (typically batch-fired log boiler appliances) may
include a manual heat exchanger/ flue cleaning mechanism for
the removal of fly ash and other combustion related deposits
8
Components of a Biomass Appliance
• Automatic Ignition System
As the name implies an automatic ignition
system may be included in a biomass appliance
to enable the combustion process to be started
without the need for manual ignition. An
automatic ignition system used in biomass
appliances is a system that utilises hot air that is
generated by a heating element.
9
Components of a Biomass Appliance (p5-6)
• Combustion Chamber
The purpose of the combustion chamber is to provide a suitable
environment in which the fuel can be burned safely and in a
controlled and efficient manner. Some biomass appliance
combustion chambers are lined with refractory brick elements to
protect the combustion chamber from premature deterioration that
can occur through excessive temperatures and the fluctuation in
combustion temperatures that occur during appliance operation.
• Combustion Controller
The purpose of the combustion controller is to automatically control
the combustion process so that optimum efficiency is achieved
during appliance operation. A combustion controller is an electronic
printed circuit board (PCB) based component. The combustion
controller operates using reference variables received from the
appliance’s lambda sensor and temperature sensors.
10
Components of a Biomass Appliance (p6)
• Fire Bed
The fire bed has a number of functions which
include supporting the fuel, preventing unburnt
fuel falling through the grate, preventing
unwanted heat transfer within the appliance
and in some appliance designs, enabling
combustion air to reach the fuel.
11
Components of a Biomass Appliance (p6)
• Flue Gas Exhaust Control
The purpose of flue gas exhaust control is to ensure that
optimum air draught conditions within the appliance are
maintained.
• Flue Gas Temperature Sensor
The appliance flue gas temperature sensor provides the
reference variable required to enable the combustion
controller to regulate the supply of primary air to the
combustion chamber. The control of the primary air supply
enables the control of the heat output from the appliance.
12
Components of a Biomass Appliance (p6)
• Fuel Store
The learner support materials for HETAS Unit HTU01K
provide details and examples of biomass and other fuel
store arrangements.
The purpose of a biomass fuel store may seem obvious
through the name of the component; however the type of
physical containment of the fuel whether it be a hopper,
silo, underground tank or log store can take many different
forms.
13
Components of a Biomass Appliance (p6)
• Heat Exchanger
The purpose of the appliance heat exchanger is to enable
the efficient heat transfer from one medium to another
i.e. in the case of a wet biomass appliance from the
fire/heated air to the heating system primary water.
• Induced Draught Fan
An induced draught fan is used to draw the combustion
gases through the appliance and into the flue/chimney
system with the primary purpose of ensuring optimum
draught within the appliance. The provision of an
induced draught fan typically ensures the highest level of
appliance operating performance.
14
Lambda Sensor (p7)
The lambda sensor (Figure 6) measures the residual oxygen level in the flue gas
as it leaves the appliance and provides the reference variable required to
enable the combustion controller or lambda controller to regulate the
secondary air and fuel feed as appropriate to achieve optimum combustion
efficiency and optimum emission values. The lambda sensor is installed in a
protective tube with a heat-resistant gasket. It is calibrated via the appliance
control system.
15
• Primary & Secondary Air Control
Primary air is delivered under the fuel bed and secondary
above. Tertiary air is a mixture of both and controlled by air
valves through the control panel.
The purpose of the primary air control is to regulate the
quantity of air that reaches the fire bed or grate in order to
control the burn rate of the fuel.
The purpose of the secondary air control is to regulate the
quantity of air that is received above the fire bed or grate to
ensure that combustion process is complete and efficient.
16
Figure 8. Example air flow regulator unit with
servo motors (p8)
17
• Suction & Drive Feed Systems for Pellet Fired
Boilers
A suction feed system may be used with a pellet
burning appliance to transfer the fuel from the fuel
store to the appliance. A drive feed system may be
used with a pellet burning appliance or a wood chip
appliance to transfer the fuel from the fuel store to
the appliance. There is a wide range of suction feed
and drive feed systems available
18
Thermal Discharge Safety Valve
19
Heat Metering
All installations eligible for RHI MUST be meter
ready.
See Page 9 of Unit 11 and MCS D-RHI Guidance.
20
Compliance Certificate
• A full heating design MUST be produced for
any biomass installation eligible for the RHI.
• The design must then be produced and
submitted as part of the MCS installation
submission documentation.
See Appendix at the rear of this Training Unit
(MCS Compliance Certificate – Biomass)
21
Calculating the Heat Load
Heat load is proportional to the heat lost from the building and by
the following factors need to be considered:
• Heat loss through the building fabric.
heat loss – through leaks in the building (adventitious
• Ventilation
air) or purpose provided.
• Domestic hot water.
• Pipe work losses.
• Exposure or geographic location of the property.
• Adjoining properties which should be assumed to be unheated.
• Intermittent heating systems which should be designed to enable
design temperatures to be achieved within a reasonable period.
22
Calculating the Heat Load
•
Fabric heat loss (Watts) = Area x U-value x Design
temperature difference ∆t
Where:
= the total area of each material type in the room
• Area
in m²
• U-value = the U-value of the material in W/m²K.
• ∆t Design temperature difference = Tin (design
temperature inside °C) – Tout (the minimum outdoor
temperature in °C)
23
Ventilation Heat Loss
The principle calculation is:
• Ventilation heat loss (Watts) = 0.33 x Volume V x Air changes N x
Design temperature difference ∆t
Where:
is a constant of the specific heat and density of air under
• 0.33
typical conditions.
• V = Volume of air in the room in m³.
• N = the number of air changes per hour.
• Design temperature difference ∆t = T in (design temperature
inside °C) - T out (the minimum outdoor temperature in °C).
24
Air Changes
• Approved Document F provides guidance on
the minimum ventilation required for new
properties in terms of litres per second, but
the following table gives typical building air
change rates for use in design calculations.
25
Design Temperature
• The design internal temperature for domestic properties is
typically given at 21°C for all rooms except bathrooms at 23°C.
Controls to limit temperature are provided so that the occupant
can increase or decrease room temperatures as required.
Increased temperature is normally specified for the elderly or
infirm.
• The normal minimum external temperature used for heat loss
calculations is dependent on location but typically is defined as
a minimum of -3°C (with an extra -0.5°C for every 160m above
sea level). The difference in the design temperatures (internal
and external) is used to calculate heat losses.
• Design temperature difference ∆t = Tin (design temperature
inside °C) - Tout (the minimum outdoor temperature in °C)
• Example, ∆t = 21°C – (-3°C) = 24°C
26
Calculation Methods
There are various methods to calculate heat loss, example
methods include:
• A detailed heat loss analysis using the longhand method as
in the DHDG.
• The Energy Savings Trust, CE 54 The Whole House
Calculation method.
• Industry software such as The HHIC Heat loss Calculator and
Radiator selector published by the Heating & Hotwater
Industry Council.
• Standard Assessment Procedure (SAP) or Reduced data
Standard Assessment Procedure (RdSAP) based software
(RdSAP will only provide a very basic heat loss calculation
and should not be relied upon for sizing biomass systems).
• Methods as suggested by MCS biomass heat loss
calculations.
27
U-values
• The resistance to which an element of the building
fabric conducts or transfers heat is known as the ‘Uvalue’ which is given as W/m²K (Watts per square
metre per degrees Kelvin).
• The U-value depends on the physical properties and
thickness of the material from which the element is
made and the external and internal surface
resistance. The smaller the U-value the better the
insulation of the building.
• Approved Document L of the Building Regulations for
England and Wales and Part 6 of the SBSA Technical
Handbook for Scotland provides the Approved
Calculating Methods. A list of U-values can also be
found in the DHDG.
28
Calculating the Heat Load
Group activity:
The next session that follows will provide you
with an understanding on how to calculate the
Heat Load for a given property utilising a
biomass appliance.
You will need to refer to your training manual
HTU11 pages 13 and 14.
29
•
•
•
•
30
Energy Consumption
Calculations to Estimate Energy Consumption
Delivered energy consumption kWh = Boiler output
kW x boiler usage hours
The following examples identify three different
methods to analyse fuel consumption. The examples
consider a property located in Wales occupied by 4
people with heat loss of 15.5kW without
consideration of hot water.
Method 1 - Basic Estimate (p14)
•
•
•
•
31
Energy Consumption
Method 2 - Seasonal Demand & Degree Days (DD).
A means to establish seasonal demand is by using
Degree Days.
This is a historical record of the temperature
difference between a base line level and the actual
temperature on an hourly basis. The standard
baseline temperature used to calculate degree days
in the UK is 15.5°C.
Degree Day figures quantify the variance in
temperature between actual and base line, for any
particular region, as a single index number on a
month-by-month basis. The long-term averages of
these figures can be obtained, by searching via the
Internet free of charge, see
http://www.vesma.com/ddd/regular.htm
32
Energy Consumption
• Method 2 - Seasonal Demand & Degree Days cont.
• The second example uses the same building heat loss
but now includes a calculation for Degree Day data
for a same property located in Wales where 1841
heating days are required.
• In reality degree days alone cannot be relied upon to
accurately calculate energy consumption.
33
Energy Consumption
• Method 3 - The Weather Factor
Using the Weather Factor has proven to provide a more
accurate method of calculating energy demand and fuel
consumption for older properties (pre 2002).
34
Calculations to Estimate Peak Fuel Consumption
• For estimating peak energy and fuel consumption during the
coldest winter months, we can predict maximum fuel
consumption for the month of January with the boiler operating
for a 12 hour heating period. The following calculations provide
an indication of the maximum amount of fuel that would be
used in a typically cold winter month of January so that peak
fuel consumption can be assessed and an allowance for fuel
storage can be made.
35
Comparing Energy Consumption Calculations
Against Previous Fuel Bills
• As a method of checking estimated energy
consumption calculations, it can be useful to
compare the calculated estimated results against
historic energy bills. Using information such as those
from fuel oil accounts or gas accounts can help
determine potential savings.
36
Domestic Hot Water (DHW) Requirements
• DHW must also be considered in the final
calculation. The extra energy demand for
domestic hot water as a general allowance of
40 litres per person per day.
37
Fuel Consumption (p17)
• Once the delivered energy consumption is
known an estimate of the annual fuel
consumption and peak fuel consumption can
be calculated to establish fuel storage
requirements and fuel delivery frequency.
38
Annual Fuel Consumption (p18)
39
Peak Fuel Consumption for January (p18)
40
Fuel Storage Volumes
• In order to calculate the fuel store volume,
and economic fuel delivery arrangements the
following parameters are required:
• Fuel consumption kg
• Density of fuel kg/m3
41
Fuel Storage Volumes
42
43
Systems Incorporating Hot Water Storage Vessels (p21)
• In many biomass installations, it is necessary to
include a vessel of heated water. The description of
which in context to the biomass industry is namely a
‘Buffer Vessel’, Accumulator’ or ‘Thermal Store’. In
principle, heated water can be generated at
maximum boiler efficiency and stored for use at a
later time, particularly when the boiler may not be
alight.
44
Systems Incorporating Hot Water Storage Vessels (p21)
45
46
Accumulator (p22)
Accumulator Sizing
• Accumulators and buffers are generally necessary
for use with log, chip and pellet boilers to reduce
cycling and essential for operation with a batch
fed log boiler.
• Unfortunately, the wide ranging performance
characteristics of different types of biomass
boiler make generalisations impossible.
Nevertheless it is very important that the heating
designer knows the principles of storage sizing.
47
Accumulator (p22)
The supplier of the biomass equipment should be
asked to size the appropriate system given the
following information:
1. The heat demand of the building
2. The nature of the heat emitters (e.g. radiators or
under floor) and their operating temperature
(e.g. 80/60°, 70/50°, 55/45°, 35/30°)
3. The firing regime required by the householder
4. The heating pattern chosen by the householder
(e.g. continuous or intermittent operation.)
48
Buffer (p23)
A buffer tank can be used to:
• Smooth demand on a chip or pellet boiler system.
• Meet demand when boiler output is low.
• Store heat for use after a batch fuelled appliance has
finished burning.
• Combine more than one heat source.
49
Buffer (p23)
50
Buffer Vessel Sizing (p24)
The capacity ratio required for a buffer vessel, measured in
litres per kW of biomass boiler rating, is dependent on many
factors:
• The type of biomass boiler grate, e.g. underfed stoker,
moving grate or stoker burner, which determines the fuel
load on the grate.
• Whether the biomass boiler is an automatic ignition boiler
or one which operates in slumber mode.
• The fuel load on the grate to be burned off prior to biomass
boiler shutdown or entering slumber mode.
• Whether a feed auger needs to be emptied onto the grate
and the fuel burned off prior to biomass boiler shutdown.
51
Buffer Vessel Sizing (p24)
• The mass of ceramic lining from which heat has to be
removed prior to biomass boiler shutdown.
• The type of fuel being burned.
• The temperature difference across the buffer vessel.
• The time to reach operating temperature on automatic
ignition biomass boilers.
52
Buffer Vessel Sizing (p24)
Rules of thumb should not be used for sizing buffer
vessels as capacity ratios vary considerably depending
on the particular combination of the above factors.
However, some typical capacity ratios for a temperature
difference of 20°C are:
• Underfed stoker boiler burning wood chips 5-10 l/kW.
• Underfed stoker boiler burning pellets 10-15 l/kW.
• Moving grate boiler burning wood chips 20-40 l/kW.
• Moving grate boiler burning pellets 30-60 l/kW.
• Stoker burner boiler 10-15 l/kW.
53
Parallel system (p25)
54
Series System (p25)
55
Thermal Store (p26)
• The thermal store can be described as a small
buffer tank normally with a capacity of 200 –
300 litres. These duties are normally limited
due to the size but even so provide a neutral
point to integrate other technologies such as
solar thermal, heat pump, room heater with
back boiler or other heating system.
• Please refer to the legends in your manual.
56
57
System Design (p27)
•
•
•
•
•
•
58
Low Temperature Distribution Systems
Factored Radiator Systems
Under Floor Heating
Weather Compensation Systems
Sealed Systems
Please refer to the paragraphs on page 27 of
Unit 11
Expansion Vessel Sizing
• In order to calculate the correctly sized
expansion vessel an assessment of the total
water content of the installed system will be
required. BS EN 12828: 2003 provides design
information for water-based heating systems
and Approved Document G requires that there
is means to resist the effects of expansion and
temperature.
59
Expansion Vessel Sizing
This may be calculated by:
• Expansion Vessel Volume= 0.156 x system volume
Information required:
The total water content of
• The pipework; (see Table 6 on page 29).
• Boiler – from manufacturer’s data sheets.
• Heat emitters to include radiators, under floor heating;
(radiator manufacturers usually show water content in
terms of section).
• Auxiliary circuits.
• Accumulator / buffer tank/ thermal store.
60
Temperature Pressure Relief Discharge Pipework
The BuildCert TMV scheme
recommends the following set
maximum mixed water outlet
temperatures for use in all premises:
•
•
•
•
61
48°C for bath fill
41°C for showers;
41°C for washbasins;
38°C for bidets.
Typical Discharge Pipe Arrangement (p31)
62
Hydraulic Design
Correct sizing, positioning and installation of circulating
pumps and valves should be carried out so the entire system
can be correctly balanced on completion. Correct sizing of
radiators, pump and tanks is imperative for efficient
operation. Guidance for this can be found in the CIBSE
Domestic Heating Design Guide.
Once the correct components have been installed, the
system should be filled, bled and the following checked
prior to commissioning.
• The circulation pump functions correctly.
• The system valves are open, including the shunt valve.
• The automatic control and safety devices are working
correctly.
63
Hydraulic Decoupling (p32)
64
Heating System Designs (p33)
65
Heating System Designs (p33)
Boiler circuit with thermostatically controlled three-way
distributor valve
66
Costs
• There are a number of factors to consider when working out the long-term
costings of an installation, including initial purchase and setup, ongoing
running costs such as fuel and routine service and maintenance.
The prices in Table 8 are a guideline only and are not definitive. They are based
on prices given by suppliers who are all accredited to either the EnPlus scheme
for pellets or the Woodsure Plus accredited by HETAS Quality Assured Fuel
Scheme and as such deliver fuel of reliable and consistent quality to all
applicable standards.
Installers and consumers should check with their local supplier directly for up-to-date prices or
information on product properties such as density or moisture content in order to make an
accurate calculation for a given installation.
67
Running Costs
• The cost of running a heating system is based on the fuel
price but must also take into account the efficiency of the
heating appliance, the control method, the geographical
location and the amount of time it is being used.
Maintenance Costs
• Maintenance costs are appliance specific and reference
must be made to the manufacturer’s recommendations.
An expected annual service and maintenance charge must
be allowed for.
68
Life Cycle Cost Analysis
• In order to make cost comparisons for different
heating systems, whether wood heating or
otherwise, it is useful to consider the costs over
the lifetime of the system.
• This costing allows us to correctly calculate the
cost per unit of energy over the life of the system
and includes the capital and maintenance costs as
well as the fuel costs.
• The cost analysis in Table 9 on page 36 only looks
at the capital and running costs over a fixed
period. This is set at 7 years to reflect the RHI
timescale.
69
Lifecycle Costing (p36)
70
Biomass Appliance Installation
Group Activity
Complete a Pre-installation checklist for a given
installation within the training centre in
accordance with Table 10 HTU11 (p37).
71
Installation Activities and Process (p38)
The typical stages and order of the installation process are:
1. Assembly and positioning the appliance.
2. Connection of the appliance to the flue/chimney.
3. Assembly and positioning of the fuel storage arrangement
(where applicable).
4. Assembly and installation of the fuel transfer system
(where applicable).
5. Connection of the appliance to the heating/hot water
system.
6. Connection of the appliance to the electrical supply and
electrical safety checks
72
Biomass Appliance Commissioning (p39-40)
• The documentation required for
commissioning to proceed
• Hydraulic circuit tightness testing, flushing and
cleaning requirements
• Equipment required for commissioning
• Pre-commissioning check requirements
• Commissioning requirements.
73
Documentation Required for Commissioning to
Proceed (p39)
• the biomass appliance manufacturer’s
commissioning instructions
• the fuel transfer system manufacturer’s
commissioning instructions (where applicable)
• instructions on the use of commissioning
equipment
• a blank commissioning record and checklist
(unless included in the appliance manufacturer’s
• commissioning instructions).
74
Hydraulic Circuit Tightness Testing, Flushing
and Cleaning Requirements (p39)
BS EN 14336:2009 states:
‘The heating system shall be pressure tested to a
pressure at least 30% greater than the working
pressure for an absolute period, as a minimum of 2
hours duration.
• Flushed and cleansed in accordance with BS7593
• Water treatment must be added in accordance
with manufacturers instructions.
• Antifreeze or supplementary heating
75
Maintenance of Equipment (p40)
• It is a requirement under MIS 3004 that
analysers are calibrated on an annual basis.
76
Electronic Combustion Analysis (p43)
Use of electronic combustion analysis equipment has
increased in recent years. The typical procedure for using
electronic combustion analysis equipment is as follows:
1. Check that any required user maintenance has been
carried out, that the unit is in good, serviceable
condition and has a current calibration certificate
2. Purge the unit using fresh air.
3. Insert the tip of the analyser probe into the centre of
the flue.
4. Allow for stabilisation.
5. Take readings.
77
Equipment Required for Commissioning (p40)
• The commissioning of a biomass appliance will
typically require the following specialist
equipment:
• Draught gauge
• Combustion analyser designed for use with
biomass (Wood pellet or Chip) appliances.
• Temperature measurement equipment
78
Commissioning Activities
• Pre-commissioning check requirements
– Refer to Table 12 (p41).
Group Activity
– Using Table 12 complete Pre-commissioning checks
• Commissioning Requirements
– Refer to Table 13 (p42)
Group Activity
– Using Table 13 complete Commissioning checks
79
Commissioning Activities
• Notification requirements (p43 & 44)
ADL states
• “Commissioning means the advancement of a fixed building
service following installation, replacement or alteration of the
whole or part of the system, from the state of static completion
to working order by testing & adjusting as necessary to ensure
that the system as a whole uses no more fuel & power than is
reasonable in the circumstances, without prejudice to the need
to comply with health & safety requirements. For each system
commissioning includes setting to work, regulation (that is
testing & adjusting repetitively) to achieve the specified
performance, the calibration, setting up & testing of the
associated automatic control systems & recording of the systems
settings & the performance test results that have been accepted
as satisfactory.”
80
Commissioning Activities
• (If MCS) MCS Compliance Certificate (p48)
• Or here
www.microgenerationcertification.org/mcsstandards/compliance-certificate
81
Handover
• The handover process will typically involve the
provision of oral and written information to
the customer or the customer’s
representative.
Refer to Section 6 (p45).
82
Decommissioning Biomass Appliances
Reasons to decommission:
• to enable servicing and maintenance work
(temporary decommissioning);
or
• because the appliance has reached the end of its
useful life, become obsolete or is inefficient
or
• Because the appliance is beyond economic repair
(permanent decommissioning).
83
Decommissioning
• Temporary decommissioning to enable servicing and
maintenance work, or
• Permanent decommissioning
Important!
It is of paramount importance that a decommissioned
solid fuel appliance is not left in a condition where the
heat exchanger is sealed or partially sealed to the
atmosphere, and there is potential for the appliance to be
re-lit. There is a potential hazard and risk of explosion if
such a situation exists.
Refer to Unit HTU11C notes on decommissioning
appliances (p46 & 47).
84
HTU12C
Biomass Appliance Service &
Maintenance
85
Requirements for the Routine Servicing of Biomass
Appliances
• The documentation required to enable routine
servicing and maintenance work (p2)
• Methods of safely isolating appliances prior to
routine servicing and maintenance (p3)
• The typical routine servicing and maintenance
requirements for biomass appliances
(Table 1, p5 & 6)
• Manufacturer’s conditions of warranty.
86
Requirements for the Routine Servicing of Biomass
Appliances
• The documentation required to enable routine
servicing and maintenance work (p2)
• Methods of safely isolating appliances prior to
routine servicing and maintenance (p3)
• The typical routine servicing and maintenance
requirements for biomass appliances
(Table 1, p5 & 6)
• Manufacturer’s conditions of warranty.
87
Methods of Safely Isolating Appliances Prior to Routine
Servicing and Maintenance
Safe isolation from the electricity supply is a requirement
under The Electricity at Work Regulations 1989 (EAWR).
88
EAWR Regulation 4 - Systems, Work Activities &
Protective Equipment
Work activities associated with electrical systems;
• Paragraph 72 In the case of work of an electrical nature it is
preferable that the conductors be made dead before work
starts. (See regulations 12, 13 and 14.) In such cases it is
essential that the equipment be isolated (note that
‘isolation’ is defined in regulation 12(2) which will include
securing by locking off etc; see also
• paragraph 75) and the conductors proved dead at the point
of work before the work starts. Where a test instrument or
voltage indicator is used for this purpose this device should
itself be proved preferably immediately before and
immediately after testing the conductors.
89
Safe Electrical Isolation Procedure
Positive or Safe Electrical Isolation
Procedure
• Before testing a circuit, you need to ensure that the
circuit is dead and isolated from the supply.
1. Locate and identify the circuit or equipment to be
isolated and the means of isolation (this could be the
fuse or isolation switches).
2. Lock off the electrical supply and place a warning sign
(e.g. ‘Safety electrician at work’).
3. Select an approved voltage indicator or test lamp.
4. Check that the device is functioning correctly on a
known supply or a proving unit.
5. Check the circuit or equipment to be worked on is dead
using the approved voltage indicator or test lamp. (Test
line to earth, line to neutral, neutral to earth.)
6. Recheck the approved voltage indicator or test lamp on
a known supply or proving unit.
90
• The operation, maintenance and testing of
electrical systems and equipment should be
carried out only by those people who are
competent for the particular class of work.
91
Safe Isolation from the Fuel Supply
• Isolation of the fuel supply is unlike gas or oil
where this fuel supply can be safely capped off.
• It may be physically necessary to prevent Solid
fuel wood and biomass transfer of fuel from the
store to the appliance.
• In addition, persons who may be or are in the
vicinity should be advised that isolation is to take
place/has taken place and warning signs/notices
should be provided.
92
Completion of a Typical Service and Maintenance
Schedule
•
•
•
•
93
Group Activity
Carry out Service & Maintenance checklist
Refer to Table 1 on pages 5-6.
Group discussion on outcomes.
Completion of a Typical Service and Maintenance
Schedule
• Group Activity
• Group discussion on defects listed in Tables 2 8 on pages 8-14 of Unit 12 including diagnosis
and rectification measures.
94
Manufacturers warranty conditions
‘If the boiler has not been commissioned, or serviced by a
competent person in accordance with the installation and
servicing manual.’ then the manufacturer’s warranty shall be
void
The RHI requires that a service plan is carried out on an
annual basis.
MCS – MIS 3004 provides that installers encourage
homeowners to have a service plan.
Source: Grant UK
95
Fault Diagnosis and Rectification Considerations
• Description of the fault symptoms and recent
system operation from the consumer.
• The system handover documentation
including the appliance manufacturer’s
installation and servicing instructions, system
design and specification documents and
commissioning records.
• Records of any previous inspection, service
and maintenance activities undertaken.
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Seminar
Q&A Session on fault finding
List the information is required to be recorded
on a maintenance report form on rectification
work? Refer to Unit 12 page 15.
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END OF COURSE
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