Quote:
Originally Posted by strider3700
do you need a 100W pump? for my solar setup I'm leaning towards something in the 10W or so range. There are tons to choose from.
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I've been thinking about how to replace that pump since the first time I looked inside the furnace. Unfortunately, the pump is part of the boiler, plus it is not standard size, so replacing it won't be easy. But I am on the lookout for something smaller, maybe a three speed unit (50/65/80W), so that I can play with the settings. My Grandma's house is very similar to our's and reducing her pump's speed (from 80W to 60W) made it much quieter without effecting how the system works, even though her house uses more energy for heating than our's.
I found the boiler's instruction manual, here is some info:
Thermal power max/min (kW): 23.1/9.2
Efficiency at nominal power (%): 90.2
Efficiency at 30% of nominal power (%): 87.8
Water temperature max/min (°C): 85/34
So the difference in efficiency between full and 30% of nominal power is only 2%. Not much. On the other hand, the boiler has never been set to more than 60-65°C, so a smaller burner (17kW instead of 23kW) would still work with no problems.