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Adjusting boiler K factor and pump delta T
I have a 150K Navien combination condensing boiler feeding 3000' of 5/8" pex in a concrete slab circulated by a Taco HEC-2 "bumblebee" pump. I am currently running the navien using the outdoor sensor at a K factor setting of 1.6 (6 is max) and the pump is currently running in constant speed mode on highest setting. I am about to change the pump over to variable speed Delta T mode but am unsure how to set it all up for maximum efficiency. The current delta T's are very high (30-40 degrees) but the system is heating the building. To lower the delta's do I want the pump to run near constantly at a lower speed and should I lower the boiler K factor and thus lower the output temp? Thanks!