5.0 Hydrotherm 58-1858 is same as Fasco 7070-003

The most important thing to know is that Hydrotherm 58-1858 is Hydrotherm's proprietary part number for what is actually a Fasco 7070-003 blower motor assembly. And the Fasco information is all that will be found on the part itself. You cannot order the part anywhere under the Fasco number, which confused our furnace service person. We, ourselves, had to locate the part and did so by calling Fasco directly. They were able to tell us that Fasco 7070-003 is available only as Hydrotherm 58-1858. Once we had that information, we found that the part is widely available. We purchased it from Industrial Stores since they had the best price (and it varies WIDELY on the internet), and we were VERY impressed that the part was on our doorstep in LESS than 24 hours. The part is installed on a Hydrotherm boiler, model HI-125B. This part was bought to replace the same part originally installed 20 years ago. So it seems to have considerable durability. The old one had begun to sound like a jet engine taking off and landing, and the new one seems to be working just fine.