The AKVAir Solar Plus is available from 300-2000 litres and is 3 bar pressure rated. The tank has 4 coils, two for solar input and two for domestic hot water (DHW) and is divided by a baffle plate, approximately 60% below and 40% above the baffle. Each section contains one solar and one DHW coil and all coils are positioned vertically.

The 4 coils are permanently fitted and are not removable as in the AKVA, AKVASAN and AKVANTTI tanks.

The solar coils are for connection to the solar array via a diverting valve to divert flow through top and bottom coil in series or through the lower coil only according to tank temperatures. The Solar Plus models are supplied with a Laddomat thermostatic diverting valve with a 53 oC cartridge.

The two DHW coils are for connection in series. A thermostatic mixing valve combination set (Oras 4200) is supplied with the Solar Plus models for regulating flow temperature to DHW.

An extra thermostatic mixing valve can be installed between the lower and upper DHW coils if desired to reduce flow through the top coil. This is not included in the Solar Plus price.

Automatic boilers, whether gas, oil, wood chip or wood pellet, are connected across the top and mid point of the tank. Batch fed boilers and stoves should be connected top and bottom to provide the full buffer volume of the tank.

Radiator circuits are normally connected flow from the top of the tank and return to mid point. Underfloor heating circuits can be connected flow from the mid point, return to the bottom. Heating flow temperature can be controlled using a 3 way blending valve and regulator such as the Thermomatic K.

Systems incorporating both radiator and underfloor heating can be connected with flow from both the top and the mid point using a 4 way bi-valent blending valve controlled by a Thermomatic K or similar. This arrangement makes use of heat energy from the mid point of the tank when available.

Akvaterm’s Solar and Solar Plus range of tanks are designed to make solar energy available to both heating and DHW. If the top of the tank is not connected to an automatic boiler capable of meeting the heating demand consideration must be given to the control of the heating to prevent depletion of the heat reserve for DHW.