We just had our Lochinvar Knight WH-055 installed. The pump is a Grundfos UPS15-58FC, its a 3 speed and is currently on medium. The contractor (a good friend of mine) did a very clean install. He is not up to date on the newest mod cons and will admit it, which is why he called Lochinvar around 8 times during the install to clarify terminology and verify the install would be correct. I don't have a camera so I can't provide a picture yet. He approached me a day ago saying that some people in the field he knows were shocked that he did not do a primary/secondary loop. To describe it, he ran 1" copper and tee'd off of it with each zone (currently 2) and it terminated into a zone. The zones all return into a 1" copper tube that returns to the boiler. The 1" supply and connected through the zones only (I hope this is understandable.) Each zone is roughly 120 feet long and it is currently 3/4" copper to baseboards. I planned on switching to pex.

My understanding was that if the supply from the boiler immediately returned then this would act like a wide open mixing valve, eliminating any ability to have condensation. I thought that you wanted as much delta t as possible (to a point). The people he spoke to are saying that the pump cant pump the water fast enough and the boiler is going to destroy itself. Currently, the boiler has been running fine for the past few weeks, and the delta t safety shutdown has not come on.(i know it works, long story)

My biggest concern is that Lochinvar verified that this would be acceptable as a set up...

What do I do if anything?