Central Heating Note Domestic wet central heating systems

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Central Heating Note: Domestic wet central heating systems operated by a gas or oil

Central Heating Note: Domestic wet central heating systems operated by a gas or oil supply are now a controlled service under the Building Regulations (Part L 1) From Plumbing (3 rd edition), R. D. Treloar, page 138 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com

Central Heating Small bore ‘one pipe’ vented heating system with gravity primaries to the

Central Heating Small bore ‘one pipe’ vented heating system with gravity primaries to the dhw Fully pumped ‘two pipe’ sealed heating system with micro-bore to first floor radiators From Plumbing (3 rd edition), R. D. Treloar, page 139 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com Domestic central heating

Central Heating vent f&e cistern cold feed branch/sub circuits are simply cut into the

Central Heating vent f&e cistern cold feed branch/sub circuits are simply cut into the main flow and return pipework heat emitters (e. g. radiators) dhw if required pump flow and return to first floor radiators cold feed dhw zone valve vent to dhw upstairs c. h. circuits one pipe system shown with gravity primaries boiler two pipe system shown with gravity primaries. This is no longer acceptable for new gas and oil installations c. h. zone valve cold feed upstairs circuits vent two pipe reversed return system air separator (shown for c. h. only) Wet central heating systems From Plumbing (3 rd edition), R. D. Treloar, page 141 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com (shown with fully pumped c. h. and dhw)

Central Heating mild steel panel radiator wheel head valve or TRV Manual, lockshield and

Central Heating mild steel panel radiator wheel head valve or TRV Manual, lockshield and thermostatic radiator valves mild steel convector radiator (the black cap shown is used to ensure the TRV remains closed when the head is removed) lockshield valve cast iron column radiator air release control panel heat sensor temperature adjusting head bellows chamber heater pressure pin fan assisted convector heater gland nut fins of fan valve packing union ‘tail’ to connect into heat emitter manual radiator valve Central heating components 1 From Plumbing (3 rd edition), R. D. Treloar, page 143 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com thermostatic radiator valve

Central Heating f&e cistern 22 mm minimum vent size f & e cistern H

Central Heating f&e cistern 22 mm minimum vent size f & e cistern H min __ 3 1 m water adjusted low in cistern to allow for expansion min pump c. h. flow boiler cold feed H __ 3 minimum pumped c. h. , gravity primaries p (found on older systems or systems u utilising solid fuel) m p c. h. return pump fully pumped system Typical c. h. pump locations air outlet washer boiler c. h. flow and return pump float rises to close valve when water enters chamber Domestic circulating pump boiler Anti-gravity valve opens only when pump is running inlet pump impeller water sucked in Central heating components 2 Automatic air release water expelled out From Plumbing (3 rd edition), R. D. Treloar, page 145 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com direction of rotation

Central Heating power supply Three port motorised valve Two port motorised valve automatic air

Central Heating power supply Three port motorised valve Two port motorised valve automatic air release valve heat emitters dhw cylinder strap to secure thermostat to dhw cylinder boiler Fully pumped systems incorporating motorised valves Basic programmer Cylinder thermostat Room thermostat Heating controls From Plumbing (3 rd edition), R. D. Treloar, page 147 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com Heating controls package (bought as a complete set)

Central Heating 150 mm maximum N N N pump Location of pump to give

Central Heating 150 mm maximum N N N pump Location of pump to give negative pressure (system works but is undesirable) f&e cistern air separator installed Cold feed and vent separated resulting Location of pump to in water pumping over the vent. Face the give positive pressure circulator (pump) in the other direction and air would be sucked in through the vent cold Illustration showing principle of correct pump location vent feed pump motorised valves flow to system boiler c. h. flow Four tapping air separator and return flow from boiler three tapping air separator (the cold feed is introduced as shown) Fully pumped system using an air separator A motorised valve ‘X’ B Example of a c. h. system showing the effects of reversed circulation A layout designed to avoid reversed circulation From Plumbing (3 rd edition), R. D. Treloar, page 149 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com Fully pumped system

Central Heating pressurised air head (by turning the head the valve will open for

Central Heating pressurised air head (by turning the head the valve will open for testing purposes) flexible diaphragm c. h. water system cold system heated diaphragm i. e. water expanded Sealed expansion vessel 3 port motorised valve high temperature alternative fill up cut out device point via a make up vessel dhw cylinder flow pressure gauge sealed expansion vessel boiler pressure relief valve tundish and discharge pipe temporary filling hose pump Pressure relief valve maximum positive pressure pump maximum negative pressure neutral point pipe circuit Note: with sealed systems the pump can be located on the flow or return because the neutral point would simply be half way round the circuit; therefore half will be under a positive pressure and the remainder negative return Sealed system illustrating a fully pumped reverse return c. h. arrangement inlet Sealed system From Plumbing (3 rd edition), R. D. Treloar, page 151 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com Illustration showing the effects of pumping in a closed circuit

Central Heating flow and return tappings Room sealed oil boiler 12 k. W electric

Central Heating flow and return tappings Room sealed oil boiler 12 k. W electric tube heater Open flue gas boiler section Typical solid fuel back boiler flow and return connections heater element refractory blocks baffles burner section wall hung balanced flue gas boilers section free standing oil pressure jet burner with open flue From Plumbing (3 rd edition), R. D. Treloar, page 153 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com Boilers fan c. h. flow and return section through an electric storage boiler

Central Heating boiler casing low water content heat exchanger pilot flame pressure deficiency valve

Central Heating boiler casing low water content heat exchanger pilot flame pressure deficiency valve micro switch Venturi multi-functional gas valve dhw valve seating pump c. h. valve seating c. h. expansion vessel dhw heat exchanger thermostatic element differential pressure valve pressure gauge pressure relief valve micro-switch discharge pipe to safe discharge point Inside view of a condensing combination boiler Note the plate heat exchanger to the bottom left and sealed expansion vessel above it. The condensing boiler principle is explained on the next page. From Plumbing (3 rd edition), R. D. Treloar, page 155 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com cold supply dhw expansion vessel gas inlet Combination boiler hot drawoff point

Central Heating air intake discharged flue gases flow water connection air intake pressure switch

Central Heating air intake discharged flue gases flow water connection air intake pressure switch ‘first’ heat exchanger ‘second’ heat exchanger return water connection burner head air supply condensate trap multifunctional gas valve forced draught gas burner gas supply Inside view of a condensing boiler Note the large heat exchanger Condensing boiler From Plumbing (3 rd edition), R. D. Treloar, page 157 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com discharge pipe run to drain or soakaway

Central Heating CO 2 gas in the atmosphere leads to global warming Trees and

Central Heating CO 2 gas in the atmosphere leads to global warming Trees and plants take in CO 2 and give off O 2 Combustion uses O 2 and gives off CO 2 gas locked up as a fossil fuel or hydrocarbon, e. g. coal, oil and methane The carbon cycle Typical legislation that enforces conservation of energy and resources From Plumbing (3 rd edition), R. D. Treloar, page 159 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com

Central Heating sealed expansion vessel temporary fill double check valve connection pressure gauge insulated

Central Heating sealed expansion vessel temporary fill double check valve connection pressure gauge insulated BS 1566 dhw cylinder thermostat band A or B high efficiency boiler pressure release valve dhw zone valve pump wheelhead valve plastic condensate drain lockshield valve upstairs zone valve room thermostat no TRV fitted in room with room thermostats room thermostat lockshield valve ground floor zone valve flow and return to further radiators drain Fully valves From Plumbing (3 rd edition), R. D. Treloar, page 163 pumped sealed heating system with two heating zones as required for dwellings over 150 m 2 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com

Central Heating Reproduced with permission from the controller of Her Majesty’s Stationery Office under

Central Heating Reproduced with permission from the controller of Her Majesty’s Stationery Office under licence number C 02 W 0007432, from Appendix G of Approved Document Part L 1 of the Building Regulations. From Plumbing (3 rd edition), R. D. Treloar, page 165 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com

Central Heating Frost thermostat Pipe thermostat Located near the coldest part of the system

Central Heating Frost thermostat Pipe thermostat Located near the coldest part of the system Located typically on the return pipe to the boiler frost thermostat pipe thermostat P electrical contacts in pump/boiler N The frost thermostat will make contact in cold weather conditions. Once the pipe thermostat is satisfied the pump/boiler will not run, therefore ‘boiler interlock’ is provided. Wiring diagram From Plumbing (3 rd edition), R. D. Treloar, page 167 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com

Central Heating Note: as the external temperature increases, cooler water is made to flow

Central Heating Note: as the external temperature increases, cooler water is made to flow around the c. h. system Weather compensation external temperature sensor Compensating system controls (shown mounted on a board for demonstration purposes) electric controller water temperature sensor 2 pipe reversed return c. h. system pump boiler by-pass modulating three port mixing valve Optimum start From Plumbing (3 rd edition), R. D. Treloar, page 169 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com External temperature control The flow temperature is continuously and automatically adjusted to compensate for changes in outside temperature

Central Heating Notes: All dimensions in metres Solid external brick wall Solid floor Single

Central Heating Notes: All dimensions in metres Solid external brick wall Solid floor Single glazed windows Double glazed doors 100 mm insulation in roof space 3 k. W to be allowed for dhw Room heights 2. 4 m 1. 0 × 0. 6 front elevation 2. 0 × 0. 6 1. 0 bedroom 18°C kitchen 18°C 3. 0 1. 0 lounge 21°C hall 18°C 1. 2 × 0. 8 bathroom 21°C 0. 5 × 0. 8 4. 0 1. 5 Radiator and boiler sizing From Plumbing (3 rd edition), R. D. Treloar, page 171 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com 1. 8 3. 0

Central Heating Assess the dwelling shape A. Simple rectangular dwelling Use worksheet alone. B.

Central Heating Assess the dwelling shape A. Simple rectangular dwelling Use worksheet alone. B. Extension and loft conversion C. Non-rectangular dwelling Use worksheet and add on radiators sizes in section 7. Divide into sections and repeat calculations. 1. Take three measurements (in meters) Length Room height Width L Number of floors w 2. Calculate TOTAL external wall areas Width No. of ext. walls x + H L w = Total ext. wall area m 2 = = x Length Room height Number of floors x x = Number of ext. walls 3. Calculate wall and window heat losses Total ext. wall area x _ Total ext. wall area Window area Table 1 Window area From Plumbing (3 rd edition), R. D. Treloar, page 175 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com Table 2 = x = A Window heat loss = x = B Wall heat loss Window area Table 3 Continue………

Central Heating Assess the dwelling shape 4. Calculate floor and roof heat losses Length

Central Heating Assess the dwelling shape 4. Calculate floor and roof heat losses Length Width Roof area Table 4 x = x _ = x Length Width C Roof heat loss 0. 7 D Floor heat loss Floor area 5. Add up fabric heat losses Table 5 = x A + B + C + D= E Total fabric heat loss (W) 6. Calculate ventilation heat loss Room height Floor area x No. of Floor x Table 5 Volume = F x 0. 25 x Ventilation heat loss (W) 7. Calculate boiler output (in k. W) E+F= Water heating (W) + 2000 = Add in any extension Divide by 1000 to get k. W From separate worksheet or radiators sizes Reproduced with permission of the Energy Saving Trust (www. est. org. UK/housingbuildings) From Plumbing (3 rd edition), R. D. Treloar, page 175 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com BOILER OUTPUT

Central Heating 1 2 2. 0 k. W 3 1. 7 k. W C

Central Heating 1 2 2. 0 k. W 3 1. 7 k. W C D 1. 8 k. W E B 4 5 3. 0 k. W boiler A F Schematic illustration of a two pipe c. h. system 2. 6 k. W G Effective pipe lengths : section A – 30 m (including flow section B – 27 m and return) section C– 10 m section D– 20 m section E – 15 m section F – 38 m section G– 19 m Pipe and pump sizing From Plumbing (3 rd edition), R. D. Treloar, page 177 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com

Central Heating From Plumbing (3 rd edition), R. D. Treloar, page 179 Copyright Blackwell

Central Heating From Plumbing (3 rd edition), R. D. Treloar, page 179 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com

Central Heating insulation ceiling joists foil backed surface heating pipes expanded metal ceiling coil

Central Heating insulation ceiling joists foil backed surface heating pipes expanded metal ceiling coil heating pipes 30 mm floor screed foil insulation dpm oversite concrete floor or ceiling coil air release valve solid floor heating coil valves to isolate circuits heating coil in wall pump boiler rendered to improve the insulation value heat resisting plaster to withstand cracking Radiant heating From Plumbing (3 rd edition), R. D. Treloar, page 181 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com wall panel pipe coil

Central Heating Underfloor heating coil being laid down From Plumbing (3 rd edition), R.

Central Heating Underfloor heating coil being laid down From Plumbing (3 rd edition), R. D. Treloar, page 183 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com

Central Heating flue pipe filter hot store vessel fan air release valve fan filter

Central Heating flue pipe filter hot store vessel fan air release valve fan filter return air heat exchanger burner forced draught warm air boiler Indirectly heated warm air system Directly heated warm air system hall return air grille warm air inlet located at low level typical inlet diffuser Warm air heating unit warm air heater kitchen return air inlet dining room heater return air grille lounge inlet diffusers hall Stepped duct system Stub duct system From Plumbing (3 rd edition), R. D. Treloar, page 185 Warm air heating Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com Radial system

Central Heating upon initial filling and flushing through remove the pump and insert a

Central Heating upon initial filling and flushing through remove the pump and insert a section of pipe wheelhead or TRV (used to turn the heater on and off) Power flushing kit Radiator balancing lockshield head removed and valve adjusted as necessary to give required heat to all emitters c. h. flow c. h. return label affixed to multifunction valve inside the boiler casing clamp-on thermometers to be used during balancing process to achieve 10°C design temperature drop across system gas supply to boiler Commissioning of wet central heating systems From Plumbing (3 rd edition), R. D. Treloar, page 187 Copyright Blackwell Publishing Ltd, all rights reserved: www. blackwellpublishing. com