| Too high can be bad:
- too much velocity can erode piping
- too much velocity is noisy
- too much velocity reduces the temperature drop of the circuit (inefficient)
- too much velocity can lead to inefficient, short-cycling boiler (inadequate temperature drop)
- high-head circulators are electricity hogs
Like Goldilocks, you want the one that is 'just right'.
One of the 3-speed circs suggested gives you three shots at choosing the right speed by flipping a switch rather than trying 3 different circs. Flying blind, however, is almost never a good thing. You should at least read up on the boiler's flow requirements, lest it succumb to an early demise (maybe the fate of the last one??)
You can also move the expansion tank connection point to the inlet side of the circulator. Often that merely requires cutting in a tee before the circulator, and piping the tank to that.
But double-check the Raypak manual on how they want their boiler piped and pumped. |