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Specifications
Draindown System
- Key Features
- Allows maximum efficiency œdirect circuit solar in frost prone regions
- Valve uses only 2 watts in operating mode (nil consumption in drain down mode)
- Controller and valve are silent during both modes of operation
- Extends solar storage cylinder life through over-temp protection
- Adapts to all direct circuit solar systems
- Supplied complete with pre-wired sensors and electrical connections
- Self diagnostic, power cut safeguard, and test facility built in.
- Sensor variables pre-loaded for installer to program
Frost Protection
When frost temperatures are detected, the solar controller is shut down and the cold water normally stored in the collectors (only 1.5 litres/collector) is drained to waste eliminating the potential of damage through freezing fluids. Once the outside air temperature rises above frost temperatures, the collectors refill and power is reinstated to the solar controller.
Extreme UV
New Zealands high UV levels over summer can result in excessive solar gain causing very high temperatures within the solar storage cylinder which reduce its working life. If the water cylinder temperatures reach the mid 80 degrees the PTR valve will blow resulting in the majority of the cylinders contents being dumped leaving the home owner without hot water, and the entire days solar energy wasted. The Metro Solar drain down system also monitors water temperatures at the top of the solar cylinder, and prior to high temperatures being reached the solar controller is shut down and the excessively hot water in the collectors (only 1.5 litres/collector) is drained to waste leaving the collectors dormant Thus eliminating the potential of the solar storage cylinder being overheated or dumping its contents. Once a reduction in cylinder temperature is detected the collectors automatically refill and solar collection restarts.
Long life, efficiency and reliability are key aims for the Metro Solar protection system. Pre-programmed temperature sets for both frost and over-temp sensors are provided, as well as incorporating self diagnostic fault monitoring resulting in the system going to drain down mode during power cuts or a controller or sensor fault being detected.
Installation Pack
The Metro Solar Frost & Over-Temperature Drain Down System is supplied as an installation pack which includes;
- Metro Solar Frost & Over-Temp Controller (complete with power supply lead, solar controller power feed, frost and over temperature sensors/leads)
- 3 port ball valve & electric actuator
- Installation & operation manual
- Solar rated check valve
- Strainer
- Top sensor attaching clip
How it works
Metro Solar Frost & Over Temperature Controller analyses data from both the external air sensor and the upper cylinder sensor, thus controlling the 3 port drain down valve, and overriding the solar controller when required.