Vaillant Low Loss Header Mixing Bottle WH40

The main purpose of the low loss header is to maintain correct flow of water through the boiler and allow a constant temperature supply of water to multiple heating circuits downstream of the low loss header connection. These heating circuits may have different temperature and flow rate requirements, (e.g. underfloor heating and radiator circuits). Cooler return water from the heating circuits is mixed with water from the boiler in the low loss header. An NTC (supplied) is used to monitor the temperature of water supplied by the boiler. It is recommended that a suitable strainer is fitted in the return flow between the low loss header and the heating circuits as a precaution to prevent system dirt from entering the boiler.