1. How to avoid melt-down of your Solar Heating System
Solar (over) Heating
How to avoid melt-down of your Solar Heating System
SH - A Miller August 2011

2. Overview Bad Experience Why did it do this Re-design Advice
SH - A Miller August 2011

3. Bad Experience Pressure excursion Melted Expansion Vessel
SH - A Miller August 2011

4. Bad Experience Pressure excursion Melted Expansion Vessel Leaks
SH - A Miller August 2011

5. Bad Experience Pressure excursion Melted Expansion Vessel Leaks
Melted pump station
SH - A Miller August 2011

6. Why did it do this Simple Layout Normal Operation PUMP STATION
EXPANSION VESSEL
TANK HEATING UP
SH - A Miller August 2011

7. Why did it do this
Tubes Designed for stagnation but not the other components
Layout
Vapour Convection
STAGNATION – VAPOUR BUBBLE - 270°
PUMP STATION
EXPANSION VESSEL
NO FLOW
Fully hot
TANK
SH - A Miller August 2011

8. Layout STAGNATION – VAPOUR BUBBLE - 270° PUMP STATION EXPANSION VESSEL
NO FLOW
Fully hot
TANK
SH - A Miller August 2011

9. Re-design
Anti-siphon loop
Secondary circuit
SH - A Miller August 2011

10. Layout – Re-design AUX. TANK (UNLAGGED) PUMP STATION EXPANSION VESSEL
SH - A Miller August 2011

11. Layout – Re-design AUX. TANK (UNLAGGED) PUMP STATION EXPANSION VESSEL
NO FLOW
Fully hot
TANK
SH - A Miller August 2011

12. Conclusions Do not assume installers know it all
Ask some awkward questions
Plumbing skill greater than average plumber’s
Layout needs careful design
SH - A Miller August 2011