OPEN VENT SYSTEMS AND SYSTEMS WITH A REMOTE PUMP

Tadpole has been designed to function in both open vent, or gravity fed systems as well as sealed systems. Where there is a remote circulation pump, thought must be given to the position of the pump in the system. On older systems, it was common practice to install the circulation pump on the primary return. If this is the case, then the Tadpole is installed within the common primary return, upstream of the circulation pump. (Fig. 1)

If the circulation pump is installed in the primary flow, Tadpole is installed upstream of the circulation pump and before any "S" or "Y"  Plan. Usually in the airing cupboard. (Fig. 2)

In the case of an "S" Plan, a proper survey must be conducted to ascertain the actual positions of either of the 2 port valves. Some installations have the domestic hot water 2 port situated near the cylinder and the heating 2 port nearer the boiler. In the case of this situation, the Tadpole may be installed in the common return, as it would be difficult to install Tadpole in the flow because of the relationship of the pump and the heating 2 port valve.

Tadpole will function just as effectively low down in the system as higher in the system nearer the cylinder.   

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

As the system is used over the next couple of weeks, all the dissolved air will be driven from the system, which will self correct as the water level drops. This is due to the amount of dissolved air found in primary systems and there is nothing more to do. The pump will become very quiet and the boiler thermostat may need to be turned down even further, please advise the owner of the system that this may be the case.

 * Tadpole will over time work just as well with the pump pushing through (Fig. 3), which is the preferred arrangement for Heat Pumps but the preferred arrangement for Open Vent and Condensing and System Boilers is as per Fig. 1 & 2 (sucking through).

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.