1. Hot Water Systems

2. Water Heating Main types From main heating system:
Regular boiler and hot water tank
Combi boiler
From additional main system
From secondary heater
Electric immersion heater
Gas multi point heater
Electric instantaneous heater
Range cooker
Community heating

3. Water Heating If the water heating is supplied by the :
main system
additional main system
secondary system
It can be identified as such in the software
Many 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 heated
Over the next few slides we will cover the different types of systems.

4. Hot Water Cylinder & Boiler – Indirect System
Immersion heater
To taps
From cold water cistern
Flow from boiler
Return to boiler
Non Condensing Regular Boiler feeding radiators and hot water cylinder.

5. Conventional System
Boiler
Sink
Mains water supply
Header tanks
Indirect hot water cylinder
Traditional system for central heating in the UK. Boiler heats up water which round heating and hot water system
Feed tank supplies water which flows between boiler and radiators
When 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 situation
This is an open vented system

6. Direct Cylinder
Immersion heater
To taps
From cold water cistern
Flow from boiler
Return to boiler
Some older systems may not have the heat exchange coil in them
These are known as ‘direct’ cylinders as the heated water goes directly into the cylinder

7. Electric Immersion - Dual
From cold water cistern
To taps
Look out for 2 hard wired switches

8. Sealed System
Sink
Mains water supply
Indirect hot water cylinder
Expansion vessel
Expansion Vessel
Boiler
Most 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

9. Pressurised System
Note the expansion vessel above the hot water tank and below the boiler
These are used to keep pressure in the system.

10. Encapsulated 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.

11. Thermal Storage System
A thermal storage water cylinder reverses the normal process
Cold 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.

12. Gledhill System
Although 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.

13. Multi Point Gas Water Heater
Normally:
Older installations
Supplies hot water only
3 pipes- gas pipe, cold water supply, hot water draw off
Often in properties with basic heating system, e.g. gas fires
Think of it as a combi boiler – but just for hot water. It heats the water as it is required, no storage

14. Electric 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.

15. Water heating from additional boiler
A boiler can provide domestic hot water only
if 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 as
Gas boiler/circulator for water heating only
Oil boiler/circulator for water heating only
Solid fuel boiler/circulator for water heating only

16. Water 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 heating
The following options are available:
Gas, single burner with permanent pilot light
Gas, single burner with automatic ignition
Gas, twin burner with automatic ignition pre 1998
Oil, single burner
Oil, twin burner pre 1998
Solid fuel, integral oven and boiler
Solid fuel, independent oven and boiler

17. Water 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 options
Hot water only community scheme – boilers
This is the most likely option as most community heating is a regular boiler system
Hot water only community scheme – CHP
This means the community system has combined heat and power, you must be sure this is present before specifying it
Hot water only community scheme – heat pump
The community heating should be a heat pump rather than standard boiler.

18. Solar Water Heating
Owner 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 roof
A store (Hot water tank)
Often additional controls

19. How Solar Water Heating Works
To taps
From cold water cistern
Flow from boiler
Return to boiler
Solar collector
Pump
Water heating system with solar collector and twin coil tank

20. Solar Heated Water
Solar 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.

21. Solar Heated Water
There are two types of collector used for solar water heating applications:
- Flat plate collectors
- Evacuated tube collectors
The flat plate collector is the predominant type used in domestic systems as they tend to be cheaper and more robust.

22. Solar Heated Water
Evacuated tube collectors are generally more expensive due to a more complex manufacturing process (to achieve the vacuum) but manufacturers generally claim better winter performance.

23. Solar Water Heating
Where solar water heating is present there may be a control panel, these are easily identified by the symbols on the screen

24. Solar Water Heating
If 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 so
Selecting ‘no’ will assume the default value, which is a 3m2 flat glazed panel on a south facing roof

25. Solar water heating - software

26. Solar water heating Extended Data to be collected:
Collector type – flat plat, evacuated tube or unglazed
Area of panel (aperture) in m2
Tilt
Orientation
Over shading
Zero loss efficiency – this figure should be in the system documentation
Heat loss coefficient - this figure should be in the system documentation
Solar store combined – is the store part of the existing hot water cylinder
Total hot water volume – if the store is combined, record the cylinder volume
Dedicated solar volume – if the store is separate, record the separate cylinder volume
Solar circulating pump – is the pump powered by electricity, PV or unknown

27. Solar 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 evidence
If the panel/collector details are available but the solar store information is not, the default values can be used for the solar store
If the solar store is combined and details are being recorded the volume of the combined cylinder must also be recorded.

28. Waste 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 system
This 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 installed
It is unlikely to be retro-fitted at a property, so it is more likely to be found in modern properties
You will need documentary evidence to include it as it is unlikely to be visible

29. Waste Water Heat Recovery

30. Waste Water Heat Recovery
As with FGHRS, WWHRS can only be recorded if it can be found in the database
Up to two of these systems can be entered
WWHRS only work in conjunction with mixer showers
You will need to determine the following:
Number of rooms with bath and/or shower (any shower)
Number of rooms with mixer shower and No bath
Number of rooms with bath and mixer shower
This information is collected for every survey regardless of the
presence of WWHRS. This data determines the recommendation
for a WWHRS

31. Waste Water Heat Recovery
Identifying mixer showers
Mixer 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 showers
Instantaneous electric showers are not included in the mixer shower count, except for ‘Number of rooms with bath and/or shower’ field 31

32. Waste 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 notes
Number 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.

33. Hot Water Cylinders

34. Hot 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 pipes
If 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 foam
Need to measure insulation thickness, with spray foam there is often a gap at the point where pipes join the tank.

35. Cylinderstat
The only control a DEA is concerned with on a hot water tank is the cylinder stat.
Usually to be held onto tank by wire
A common misconception is that a TRV can count as a cylinderstat.

36. Combined Hot and Cold Water Storage Unit
Cold feed
Flow from boiler
Return to boiler
Mains feed
Hot water
Immersion heater

37. Typical Hot Water Cylinder Sizes
Getting the Cylinder size is crucial in your assessment this guide will help you
Normal Size – 130 Litres
Medium Size Litres
Large Size > 170 Litres
Dimensions H x W
Litres
825 x 450
900 x 400
900 x 450
1050 x 400
1050 x 450
1500 x 450
110 96
120
115
144
218

38. Software

39. Any questions?