When installing a wood burning stove or cooker with a boiler, we use a hybrid heating system with a thermal store to allow several heat sources to work together to manage your central heating and hot water. Our heating engineer can carry out a site survey and make his recommendations, or you could arrange an appointment to meet him at our showroom in Canterbury for an initial chat. You are of course very welcome to pop in anytime to discuss stoves with our showroom staff, but for more technical advice about the heating system it’s best to call ahead to be sure to catch our heating engineer.

If you would like more information you can contact Graham at sales@cosi.co.uk giving as much information about your current system and your requirements as possible.

Thermal Stores

The thermal store concept has been around for many years now, and I have personally used one in my home for 15 years. The beauty of the system is in its simplicity, with 2 or more boilers/heat sources connected together without the need for electronics, valves or human interference.

Some manufacturers advocate the use of cheaper plate heat exchangers. There are a number of problems with this design;-

  1. The passage ways on a plate heat exchanger are very small, in a hard water area a water softener must be used, plus a filter system, otherwise this type regularly clog up and need replacing. (They are used in all gas combi boilers, hence the low cost and short life)
  2. No electricity – No hot water, as they require a pump and flow switch.
  3. Pumps and flow switches wear out and go wrong so require more maintenance, servicing, and of course cost in the long run.

With the above problems and very little cost saving by the time you have bought the pumps and fittings, I cannot see any advantage in using a plate heat exchanger system.

Our thermal stores have a 12 meter long 15mm diameter finned copper coil. The output depends on the house flow rate and the temperature inside the store but is easily 25-30 litre/min. More than enough for 2 showers and basins. If you need more hot water, 3 bathrooms or more, you are better off with 2 cylinders, and with charging the second hot water cylinder indirectly from the thermal store. Either a pump fed, unvented, or using conventional cold water tanks in the loft. Putting in more plate exchangers or large thermal stores will not help as they will be constrained by the flow of water into the house.