COMBINATION AND SYSTEM BOILERS

The circulation pump of a combination, and a system boiler is generally installed within the primary return. Therefore Tadpole should be installed within the primary return. (Fig. 1) It does not need to be close to the boiler and can be effectively installed under the boiler.

The Tadpole may create a little noise at first, this is due to air in the system. This will disappear and the system will quieten down as it heats up. The heat up time should be shorter than before and the primary water will become hotter. It may be necessary to reduce the thermostat setting of the boiler once the system has been running for about 20 minutes.

With regard to condensing boilers, it will still be necessary to turn down the primary thermostat, initially by approximately 10°C, and still further after Tadpole removes all the dissolved air. With condensing boilers that don't have a digital temperature display, the thermostat will need to be turned down by approximately 1/4 turn. Eventually it will need reducing to one third of the original setting.

As the system is used over the next couple of weeks the system pressure may drop to virtually zero which will prevent the boiler from igniting. Advise the system owner that it will be necessary to top the system up back to 1-1.5 bar working pressure when this happens.

We would recommend the fitting of Gate Valves on either side of Tadpole to facilitate the replacement or maintenance of the Air Vent if required. Alternatively a Shut Off Valve can be supplied for Tadpole at an extra cost.