Coldstream Hot & Cold Water Control
Product Features
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All taps and showers are at the maximum incoming mains pressure.
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Provides increased water flow rate to both hot and cold water outlets.
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Suitable for properties with very low mains flow rates (9 litres per minute).
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Suitable for properties small bore (15mm) mains feed.
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Balanced Hot and Cold water supply pressures.
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Minimal pressure drop when more than one tap is in use.
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No loft storage tank - no risk of water stagnation.
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Completely sealed system, low risk of Legionella.
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Wholesome water to all cold taps.
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No tank filling noise.
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Coldstream utilises GREEN TECHNOLOGY, no electrics or wasted energy.
Coldstream Application
The Coldstream range of Accumulators from GAH Heating Products has been designed for installation on mains fed systems, to provide increased flow rates and stabilize pressure problems. When installed on a main supply feeding a "Combination Boiler, it will ensure maximum flow rate through the boiler when other outlets are turned on, and stop pressure fluctuations provided the Accumulator and pipework is sized correctly. Although the performance will be greatly improved, you cannot improve on the combination boilers maximum given hot water output. When installed on existing unvented systems you create the Dualstream principle and maximise the cylinders performance and that of the balanced cold supplies, by increasing the volume through the Accumulator. The larger the Accumulator the longer the performance can be maintained. Other factors need to be considered when sizing or choosing the Accumulator model.
GAH strongly recommend that pressure and flow readings are undertaken to establish whether there is a flow rate or pressure problem. The
Accumulator can be installed anywhere on the main supply entering the property, basement, utility, loft etc. and there must be a check valve installed on the main supply and 3.5 Bar pressure reducing valve if the pressure is likely to rise above 5 Bar. The air charge in the Accumulator is factory set at 2 Bar but may require adjusting so that it is between 1-1.5 Bar below the mains pressure minimum vessel pressure 0.5 -0.8 Bar, (consult GAH if lowering to this pressure) to allow water to enter the vessel. The lower the mains pressure the less water that can be stored in the Accumulator, so always remember to oversize the Accumulator by at least one or two sizes larger than the unvented cylinder or flow rate requirements.
GAH offer a full design service and technical assistance and work closely with companies to resolve situations regarding poor main supplies and volume problems.
For larger installations and future projects, GAH offer the Dualstream system which combines both an Accumulator and an unvented hot water cylinder for a complete hot and cold water system.
GAH Dualstream System
The Dualstream system utilises an Accumulator, which has a controlled butyl diaphragm that stores cold mains water at mains pressure and a range of stainless steel unvented cylinders. When a tap or shower is turned on the Accumulator enhances the main supply and helps maintain the pressure to all hot and cold outlets regardless of the flow rate on the incoming main supply enabling more than one outlet to be run at the same time giving.
Technical Diagram
System With Combination Boiler
shows typical configuration of a Coldstream system connected to a Combination boiler.
Coldstream can be fitted to existing Combi systems providing all criteria as specified in this manual are met.
The incoming mains supply is connected to the Accumulator. A Double Check Valve is supplied with the Coldstream system, if one is not already fitted, this should be fitted to the mains supply prior to any connections or take offs to prevent back flow and to maintain Accumulator pressure.
Provision must be made, as applicable, for:- outside tap, boiler/heating system fill and water softener.
If the mains pressure fluctuates or is over 4 Bar, a Pressure Reducing Valve must be fitted.
Supply to all the cold taps and boiler is taken from the Tee fitting at the base of the Accumulator.
Supply to the hot taps and outlets from the Combination Boiler.
As the cold flow to a bath from the Accumulator will be considerably more than the hot flow from the combination boiler it is recommended to fit a flow restricting valve to the bath cold supply to balance hot and cold flow from the taps.
One full bore lever valve is supplied, it is recommended to install this on the cold supply from Accumulator. Other shut off valves may be required depending on installation. Drain offs must be provided to enable the system to be fully drained.
Recommended Accumulator Size
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Boiler Type |
Combi |
Combi store |
|
Accumulator Model |
200-240 |
240-300 |
Sizing Of System
The size of the Coldstream system is determined by the capacity of the Accumulator selected and the following criteria. As the Accumulator provides increased flow rates and maintains system pressure it is important that this is of adequate size.
The Accumulator water content is up to 65% of its gross volume.
When sizing the Coldsteam system close consideration should be given to the following:-
1. Incoming mains supply pipe size (Coldstream can be installed on a
15mm main).
2. Incoming mains flow and static pressure.
3. House type, building height and number of occupants.
4. Typical daily water usage and peak demands.
5. Number of bathrooms and total number hot and cold water outlets
6. Types of shower, taps and baths and the volume and pressure of water
to operate them.
The following chart is given as a guide only.
|
Size of Dwelling |
Small Flat |
Flat Smaller House |
Small House |
Medium House |
Larger House |
Large House |
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Usage |
Kitchenette Electric Shower Basin |
Kitchen 1-2 Bedrooms 1 Bath & Shower |
Kitchen Cloakroom 2-3 Bedrooms 1 Bath & Shower |
Kitchen, Cloakroom 4-5 Bedrooms 2 Baths & Showers |
Kitchen, Cloakroom Utility Room 4-6 Bedrooms 2 Baths & Showers |
Kitchens, Cloakrooms Utility Rooms Multiple Beds 4-5 Baths & Showers |
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Preferred Accumulator Model |
100 |
100 200 240 |
200 240 300 |
240 300 500 |
300 500 |
500 2x500 |
Accumulator Dimensions
Pumped Borehole / Well Applications
The Coldstream system can be used in applications where the cold supply is pumped from a well or borehole using a dedicated controlled submersible pump.
Existing borehole/well and pump arrangement must be fully inspected and confirmed suitable for Coldstream application.
The pump should capable of delivering a minimum of 9 litres per minute @ 1.5 to 3 Bar pressure and controlled by a pressure switch.
Fig. 1-2e shows a typical borehole application.
To protect the pump a smaller Accumulator can be connected prior to the pressure reducing valve and double check valve, this will absorb any over pressure from the pump.
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Coldstream 100 |
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|
Capacity (Litres) |
Diameter (mm) |
Height (mm) |
Weight Full (kg) |
|
100 |
410 |
895 |
118.6 |
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*NOTE: Accumulators hold up to 60% of the cylinders' capacity in mains water with the remaining 40% taken up with the positive air charge designed to force the water from the vessel. We recommend over sizing the accumulator vessels where possible, taking into consideration the mains supply. |
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Coldstream 200 |
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Capacity (Litres) |
Diameter (mm) |
Height (mm) |
Weight Full (kg) |
|
170 |
535 |
920 |
200.4 |
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*NOTE: Accumulators hold up to 60% of the cylinders' capacity in mains water with the remaining 40% taken up with the positive air charge designed to force the water from the vessel. We recommend over sizing the accumulator vessels where possible, taking into consideration the mains supply. |
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Coldstream 240 |
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|
Capacity (Litres) |
Diameter (mm) |
Height (mm) |
Weight Full (kg) |
|
240 |
535 |
1215 |
277.2 |
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*NOTE: Accumulators hold up to 60% of the cylinders' capacity in mains water with the remaining 40% taken up with the positive air charge designed to force the water from the vessel. We recommend over sizing the accumulator vessels where possible, taking into consideration the mains supply. |
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Coldstream 300 |
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|
Capacity (Litres) |
Diameter (mm) |
Height (mm) |
Weight Full (kg) |
|
310 |
535 |
1575 |
354.5 |
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*NOTE: Accumulators hold up to 60% of the cylinders' capacity in mains water with the remaining 40% taken up with the positive air charge designed to force the water from the vessel. We recommend over sizing the accumulator vessels where possible, taking into consideration the mains supply. |
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Coldstream 500 |
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|
Capacity (Litres) |
Diameter (mm) |
Height (mm) |
Weight Full (kg) |
|
450 |
668 |
1575 |
519.5 |
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*NOTE: Accumulators hold up to 60% of the cylinders' capacity in mains water with the remaining 40% taken up with the positive air charge designed to force the water from the vessel. We recommend over sizing the accumulator vessels where possible, taking into consideration the mains supply. |
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