RAYBURN
COOKERS
INSTALLATION
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DOMESTIC HOT WATER
Heatranger Models with twin burners.
440K, 460K, 480K, 499K, 480CD, 480AL CF, 480AG CF, 880K, 8120K, 8150K
On these models, domestic hot water is generated solely by the boiler burner and not as a by-product of cooking operations. Consequently, it can be time-controlled by the integral programmer and temperature managed by external devices such as a cylinder thermostat in conjunction with motorised zone-valves.
A fully pumped, indirect system is required, similar to that shown below, noting that the diameter of the flow and return pipes should be 28mm for the 460, 480, 499K and 800 series models and 22mm for the 480CD, 480AG CF & 480AL CF.
Motorised valves may be of the 3 port, mid-position type or 2 port zone variety. For use with the 460,480,499K models, it is important to select the correct type and size as follows.
| Model | 2 Port Zone Valve | Mid Position Valve |
| 440K, 460K | 22mm | 22mm |
| 480K | 28mm | 28mm |
| 499K, 880K, 8120K, 8150K | 28mm | Do not use |
The Rayburn incorporates its own pump over-run control, therefore it is necessary to provide a bypass circuit, in circumstances where zone valves are fitted which can completely close. This bypass could incorporate a heat leak such as a towel rail, but otherwise should provide a pipe-work loop of at least 5m from the Rayburn, sufficient to discharge the latent heat. An automatic pressure adjusting valve should be fitted to the bypass.
The hot water produced must be stored in an appropriate copper cylinder, although there is a considerable number of options suitable for use with these models. Electric immersion heaters may also be incorporated.
For most households a storage capacity of between 140-190 litres (35-40 gallons) should be sufficient on conventional, vertical, indirect copper cylinders, although proprietary 'quick recovery' cylinders may be significantly smaller.
Some types of Open-vented, 'Thermal store' type cylinders may be used, thereby providing the domestic hot-water at mains pressure, which is useful for shower installations. The cylinder manufacturers installation instructions should be followed
.
There is also a wide range of proprietary un-vented hot-water cylinders available which can also be used in conjunction with these models of Rayburn. The cylinder manufacturer's guidelines must be carefully followed as regards compatibility and the requirements for any necessary additional control devices.
Since these models incorporate a manual reset overheat device, it is possible to use a sealed system as an alternative to the conventional open-vented arrangement. Sealed systems, set to operate at a maximum pressure of 2 bar, will require the appropriate ancillary equipment, such as expansion vessel, pressure relief valve and filling loop.
The plumbing system should be fully flushed through and a suitable corrosion inhibitor added.
The system must be installed in accordance with local water bylaws, Building Regulations and British standards and we strongly encourage that the plumbing be carried out by a competent person.
See also.