Pressure and flow readings need to be taken by the heating engineer, local water authority or competent person, these readings will confirm where the problem lies and consultation with GAH can confirm the suitability of our system.

Yes renewing old supplies are good practice and essential for standard unvented cylinders to perform well. Dualstream systems can be connected to 15mm mains supplies given that the accumulator is sized correctly.

Dualstream systems can be connected to shared mains supplies given that the accumulator is sized correctly it will work and function properly.

Yes, Dualstream systems can be connected to a bore well installation given that the accumulator is sized correctly

Yes, the design of the accumulator makes it ideal to be installed anywhere on the main supply and with no power supply requirements or discharge pipe required they can be installed in basements, lofts, garages, sheds even outside protected from the elements.

We have been producing and selling Dualstream systems and accumulator technology for over 9 years

We offer sales and technical support and a design service, and if your heating engineer is familiar with unvented cylinders then the accumulator is simply one or two connections more than that of installing a standard unvented cylinder

Yes that is true Unvented cylinders or mains pressure systems above 15 litres must comply to building regulations G3 and Building regulation L part 1-2. These regulations are there to cover the safety and efficiency of the product and the installation being carried out by a competent person. If considering installing any unvented system you should notify local building control and the local water authority, or the installation company may do this on you behalf.

Our systems are sold into the Merchant stockists and GAH deal withal the major groups and many of the independents, delivery lead-times are around 5-7 days. Link stockists

We offer a design service, where we can look at plans, e-drawings, CAD drawings and offer our technical support, we can also visit the site if required.

Yes, Heating engineers must show competency and they must do this by completing one of the many unvented training courses in the UK such as CITB, Zurich BPEC, these courses are run by training companies and give the installer the correct training to pass the exam and then be qualified to install, service and commission unvented cylinders. The heating engineer is then given a card showing his certificate number. Any good reputable heating engineer or company will also offer you recommendations from other customers, which is also worth having.

Your first step would be to talk to a heating engineer or company to discuss your requirements and get an idea of costs and the amount of work required to install the products and the amount of time and disruption. We offer sales and technical support and we can also offer you the option to discuss the matter with one of our Dualstream heating engineers/agents, depending on the area you live in. They are heating engineers that have been given the appropriate training and promote our products within there normal roles as heating engineers running there own companies.

Dualstream and Coldstream systems are available through the merchant trade and depending on your requirements will depend on the model you require and ultimately the costs. If you contact us directly we can give you an idea of cost and discuss your requirements and the next steps to purchase our systems.

We pride ourselves in trying to offer the best advice and system design for customers requirements. We have an open and honest approach and have many years experience in the heating and hot water industry. We do offer site visits where possible if issues cannot be resolved by other mediums.

Yes our systems have been designed to work on 15mm main supplies and shared supplies. We recommend that pressure and flow readings are taken and that the accumulator is oversized to accommodate the smaller pipe size. The lower the pressure and flow rate the bigger the accumulator.

The lowest pressure would be 1.5 bar and the flow rate 9 litres and with these sort of readings we would recommend discussing your requirements with a member of the Dualstream team to get the right amount of accumulated stored water.

No, accumulators are designed to increase flow rates while stabilizing the pressure or maintaining the pressure for as long as there is adequate water stored in the accumulator, then when empty it will return to the performance of the main supply.

Yes the accumulator design if sized correctly will increase flow rates on mains supplies feeding unvented cylinders, combination boilers and electric showers and much more, please refer to Coldstream information.

All accumulators are now supplied with a factory pre- charge pressure of 1.4 bar, and can be adjusted depending on the incoming mains pressure as described in our installation manual page 29. Normally 1.5 bar below mains pressure. With the mains supply off and the accumulator empty the air can be adjusted through the Schrader valve on the top of the vessel using a good quality pressure gauge. If air charge needs to be increased then the same process can be used using a small compress.

This is not recommended as the vessels have been designed to be installed in a vertical position. With models up to 240 it is possible, but only used as a last result as it is likely to lesson the life expectancy of the vessel.

No not really the air charge in the vessel can be checked from time to time along with a visual inspection, there are no moving parts or valves to be serviced.

The cylinders we supply as part of the Dualstream system are supplied with external expansion vessels sized to the capacity of the cylinder.

Yes, we offer a range of water softeners and with the right size hose kit and installed before the system on the main supply.

Yes we all have our own opinion on plastic pipe, but there is no reason why this cannot be used, if installed properly. I would recommend that some copper pipe work around the cylinder offers greater rigidity and strength, but supplies to hot and cold outlets would be fine.

Well how long have we got! This is most common problem to do with unvented cylinders and the most talked about, with many engineers with years of experience still taking there own views on discharge arrangements. We have shown in our installation manual the guide to discharge pipe-work and sizes and it is the building control officer that generally has the last say. The d1 discharge normally now in 15mm runs to the tundish-air gap which must be no greater than 500mm from the T/P valve the D2 pipe - work is then calculated depending on runs and elbows and sweep bends are treated the same as elbows. You must have a 300mm straight drop before your first bend/ elbow, the termination point must be visable in most cases and safe and all discharge pipe work must be metal as described in G3, more info can be found in our manual or the G3 building document. Now the G3 document is currently being revised and Hepworth products have applied to BRE and had passed and obtained a certificate on the HEPVO trap for use on discharge pipe work for unvented cylinders. So yes this method could be used using this trap and the correct BS approved plastic pipe as described by Hepworth. I would also inform the building control officer that this method will be used and a copy of the BRE certificate. The installation guide supplied by Hepworth clearly states the installation method, trap and adaptors to be used. If you need further assistance please contact one of our technical advisors.

Yes we offer two sizes 210 and 300 and the twin coil can be used for Solar, ground heat source or other renewable energies with temperature control.

Yes the accumulators require no power supply or discharge pipe- work so no problem. The unvented cylinders can also be installed in the basement, but you must allow for the arrangement of the discharge pipe-work, normally into a metal tank and sump pump and pumped to a higher level.

The coil sizes range between 26.7 and 31kW and my advice is that most unvented cylinders have quicker recovery times compared to traditional cylinders depending on the heat input and the way the system is controlled. I feel that you should look to allow a minimum of 6-10 kw above the heating demand for the boiler, higher if quicker recovery times are needed.

Yes you could but you must still install the two port valve supplied, so it is easier and more widely accepted to connect to a s-plan system, as you have to use the valve supplied anyway.