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Viessmann 200-19 pump question.
Viessmann has the Grundfos 15-58 3 speed on it's list for the indirect water tank loading pump. It seems this is also fine for the system pump for LLH loop. I see some installed systems with the Alpha 15-55 pump -- I'm guessing for the lower electric cost. I can see the savings for the system side since it's running 1/2 the year ... but, the indirect pump is not going to run all that much. Are the alpha pumps reliable? The cost difference is not that much .. but I don't want to install a less reliable pump.
I guess the 15-42 is now obsolete ...?