2Water Heating Main types From main heating system: Regular boiler and hot water tankCombi boilerFrom additional main systemFrom secondary heaterElectric immersion heaterGas multi point heaterElectric instantaneous heaterRange cookerCommunity heating
3Water Heating If the water heating is supplied by the : main systemadditional main systemsecondary systemIt can be identified as such in the softwareMany hot water tanks have electric immersion heaters fitted, but they are only used as a back up, and are not the main way the water is heatedOver the next few slides we will cover the different types of systems.
4Hot Water Cylinder & Boiler – Indirect System Immersion heaterTo tapsFrom cold water cisternFlow from boilerReturn to boilerNon Condensing Regular Boiler feeding radiators and hot water cylinder.
5Conventional SystemBoilerSinkMains water supplyHeader tanksIndirect hot water cylinderTraditional system for central heating in the UK. Boiler heats up water which round heating and hot water systemFeed tank supplies water which flows between boiler and radiatorsWhen heated this water expands- if heating controls go wrong the water may give off steam or even boil. Expansion pipe discharges to feed and expansion tank, this gives the heating system an outlet to release pressure in this situationThis is an open vented system
6Direct CylinderImmersion heaterTo tapsFrom cold water cisternFlow from boilerReturn to boilerSome older systems may not have the heat exchange coil in themThese are known as ‘direct’ cylinders as the heated water goes directly into the cylinder
7Electric Immersion - Dual From cold water cisternTo tapsLook out for 2 hard wired switches
8Sealed SystemSinkMains water supplyIndirect hot water cylinderExpansion vesselExpansion VesselBoilerMost condensing boilers are fitted in a sealed system which has no expansion tanks, just small expansions vessels which take the pressure in the system.No traditional expansion tanks, pressure contained in pressure vessels
9Pressurised SystemNote the expansion vessel above the hot water tank and below the boilerThese are used to keep pressure in the system.
10Encapsulated cylinders Encapsulated cylinders like this becoming more common, appear a lot in recently built properties.Tend to have a hard casing, cannot access insulation. Try and get manufacturers details in order to research, manufacturers website tend to have spec. It is fair to assume 50mm of spray foam insulation.Megaflo systems like this becoming more common, appear a lot in recently built properties.Tend to have a hard casing, cannot access insulation. Try and get manufacturers details in order to research, manufacturers website tend to have spec. It is fair to assume 50mm of spray foam insulation.
11Thermal Storage System A thermal storage water cylinder reverses the normal processCold water from the mains enters the coil at the top of the tank and is heated by the surrounding hot water before outputting to the taps.Hot water is therefore effectively provided on demand and at mains pressure.
12Gledhill SystemAlthough this system is more efficient than a standard central heating system, RDSAP cannot account for it.If you come across a thermal storage system like this then treat it as a standard system with regular boiler and hot water tank.
13Multi Point Gas Water Heater Normally:Older installationsSupplies hot water only3 pipes- gas pipe, cold water supply, hot water draw offOften in properties with basic heating system, e.g. gas firesThink of it as a combi boiler – but just for hot water. It heats the water as it is required, no storage
14Electric Instantaneous at Point of use Water Heaters In smaller properties you may come across this method of providing hot water.Usually a small unit located near the sink in the kitchen or bathroom.It heats the water as required, like an electric shower.
15Water heating from additional boiler A boiler can provide domestic hot water onlyif the specific boiler can be found on the boiler database it can be entered as additional heating, with the floor area it heats entered as 0% and the water heating ‘from additional heating’If the boiler is not on the database it should be entered in the water heating section only, and not as additional heating. The type of boiler can be specified asGas boiler/circulator for water heating onlyOil boiler/circulator for water heating onlySolid fuel boiler/circulator for water heating only
16Water heating from Range cooker If the water heating is supplied by a range cooker which does not provide the main heating then it can be specifically identified in the water heatingThe following options are available:Gas, single burner with permanent pilot lightGas, single burner with automatic ignitionGas, twin burner with automatic ignition pre 1998Oil, single burnerOil, twin burner pre 1998Solid fuel, integral oven and boilerSolid fuel, independent oven and boiler
17Water heating from community heating If the community heating is providing domestic hot water only it can be specified in the water heating section as one of the following optionsHot water only community scheme – boilersThis is the most likely option as most community heating is a regular boiler systemHot water only community scheme – CHPThis means the community system has combined heat and power, you must be sure this is present before specifying itHot water only community scheme – heat pumpThe community heating should be a heat pump rather than standard boiler.
18Solar Water HeatingOwner will tend to have a good understanding of the system, they are best source of info about individual system.If a property has solar heated water there must be:Solar panels on roofA store (Hot water tank)Often additional controls
19How Solar Water Heating Works To tapsFrom cold water cisternFlow from boilerReturn to boilerSolar collectorPumpWater heating system with solar collector and twin coil tank
20Solar Heated WaterSolar water heating systems use the energy from the sun to heat water, most commonly in the UK for domestic hot water needs.The systems use a heat collector, generally mounted on the roof in which a fluid is heated by the sun.This fluid is used to heat up water that is stored in either a separate hot water cylinder or a twin coil hot water cylinder inside the building.The systems work very successfully in all parts of the UK, as they can work in diffused light conditions.
21Solar Heated WaterThere are two types of collector used for solar water heating applications:- Flat plate collectors- Evacuated tube collectorsThe flat plate collector is the predominant type used in domestic systems as they tend to be cheaper and more robust.
22Solar Heated WaterEvacuated tube collectors are generally more expensive due to a more complex manufacturing process (to achieve the vacuum) but manufacturers generally claim better winter performance.
23Solar Water HeatingWhere solar water heating is present there may be a control panel, these are easily identified by the symbols on the screen
24Solar Water HeatingIf this system is present there will be a ‘yes/no’ option in the software. Selecting ‘yes’ will give you the option to enter further details.As with other manual entries, documentary evidence must be supplied in order to do soSelecting ‘no’ will assume the default value, which is a 3m2 flat glazed panel on a south facing roof
26Solar water heating Extended Data to be collected: Collector type – flat plat, evacuated tube or unglazedArea of panel (aperture) in m2TiltOrientationOver shadingZero loss efficiency – this figure should be in the system documentationHeat loss coefficient - this figure should be in the system documentationSolar store combined – is the store part of the existing hot water cylinderTotal hot water volume – if the store is combined, record the cylinder volumeDedicated solar volume – if the store is separate, record the separate cylinder volumeSolar circulating pump – is the pump powered by electricity, PV or unknown
27Solar water heating RdSAP convention 9.09 states: Documentary evidence is required to over-write collector or solar stone values except that orientation, tilt and overshading can be overwritten with visual evidenceIf the panel/collector details are available but the solar store information is not, the default values can be used for the solar storeIf the solar store is combined and details are being recorded the volume of the combined cylinder must also be recorded.
28Waste Water Heat Recovery What is it?A waste water heat recovery system (WWHRS) uses a heat exchanger to recover heat from waste warm water as it flows through the waste plumbing systemThis is used to pre-heat the cold water feed of a shower, combi boiler or hot water cylinder.The energy recovered depends on the temperature of the cold water feed to the dwelling (which varies by month) and the number and type of systems that are installedIt is unlikely to be retro-fitted at a property, so it is more likely to be found in modern propertiesYou will need documentary evidence to include it as it is unlikely to be visible
30Waste Water Heat Recovery As with FGHRS, WWHRS can only be recorded if it can be found in the databaseUp to two of these systems can be enteredWWHRS only work in conjunction with mixer showersYou will need to determine the following:Number of rooms with bath and/or shower (any shower)Number of rooms with mixer shower and No bathNumber of rooms with bath and mixer showerThis information is collected for every survey regardless of thepresence of WWHRS. This data determines the recommendationfor a WWHRS
31Waste Water Heat Recovery Identifying mixer showersMixer showers take water from both hot and cold water supplies.They mix the hot and cold together to reach a desired temperature.They generally flow faster than electric showersInstantaneous electric showers are not included in the mixer shower count, except for ‘Number of rooms with bath and/or shower’ field31
32Waste Water Heat Recovery RdSAP convention 9.08 states:Include only if found in database. When the model cannot be found no default option is available but the presence of the device should be recorded in site notesNumber of rooms with bath and/or shower includes rooms with only an electric shower. If two showers found in a room count as one.Only mixer showers count for waste water heat recover. Mixer shower means a shower where the hot water is provided by a boiler (combi or regular), heat pump or immersion heater. A mixer shower attached to bath taps is recorded as a mixer shower only if there is a permanent bracket over the bath and there is a shower curtain or screen.
34Hot Water Tanks - Insulation The thickness of the insulation should be measured at a point where you can get through to the cylinder.With spray foam find an area where the foam has been cut away for connecting pipesIf the insulation thickness falls between two options in the software then go with the lesser of the two.This is very common, jacket or spray foamNeed to measure insulation thickness, with spray foam there is often a gap at the point where pipes join the tank.
35CylinderstatThe only control a DEA is concerned with on a hot water tank is the cylinder stat.Usually to be held onto tank by wireA common misconception is that a TRV can count as a cylinderstat.
36Combined Hot and Cold Water Storage Unit Cold feedFlow from boilerReturn to boilerMains feedHot waterImmersion heater
37Typical Hot Water Cylinder Sizes Getting the Cylinder size is crucial in your assessment this guide will help youNormal Size – 130 LitresMedium Size LitresLarge Size > 170 LitresDimensions H x WLitres825 x 450900 x 400900 x 4501050 x 4001050 x 4501500 x 45011096120115144218