central heating pump settings
- Thread starter ih
- Start date
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Strictly speaking the 'pump' is not a pump, but a circulator..which is different. However we all call them pumps, so here goes.
The lowest speed at which your system works is the correct speed. I'd ignore speed 1 and start with 2, and see how it goes. If you have to use speed 3 you run the risk of impeller cavitation..which means the impeller hits the water so hard it knocks the oxygen out of it (like the bubbles that come off a ships propeller). This oxygen migrates to the highest point and you get air in the system.
If you can only get the system to work on speed 3, and you do get air in the system (rads cold at top, hot at bottom) then you need a circulator with a larger capacity to achieve the same circulation at a lower speed.
You could buy one of those posh modulating pumps that reacts to the load on it..Grundfos Alpha etc, but we have not had great success with them, and end up using the manual settings ..which rather misses the point of shelling out for one
Alfredo
The lowest speed at which your system works is the correct speed. I'd ignore speed 1 and start with 2, and see how it goes. If you have to use speed 3 you run the risk of impeller cavitation..which means the impeller hits the water so hard it knocks the oxygen out of it (like the bubbles that come off a ships propeller). This oxygen migrates to the highest point and you get air in the system.
If you can only get the system to work on speed 3, and you do get air in the system (rads cold at top, hot at bottom) then you need a circulator with a larger capacity to achieve the same circulation at a lower speed.
You could buy one of those posh modulating pumps that reacts to the load on it..Grundfos Alpha etc, but we have not had great success with them, and end up using the manual settings ..which rather misses the point of shelling out for one
Alfredo
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