Best Of

NOTHING made now will last 10 years never mind 75. Even if it is the same "identical " pump it is likely made in China or some of the parts are.

There is probably twice the copper in that old motor as a new motor. Take care of it. The volute and housing are probably fine. The motor can be rebuilt at a motor shop and new bearing assemblies are available, I think unless they changed th thing so a new one will not fit.

But you will need a truck to haul the money from your bank to Bell & Gosset. They give nothing away.

That's not a 100. Note the 4 bolt flanges, and flange to flange height difference.

Looks like all you need is a flat-bladed screwdriver. And from that drop down screw, you have a Viessmann boiler.

Why do you want to flush your boiler? It should not be flushed unless there's air or a clog you want removed.

Several drops of oil in the pump oil port, a couple of drops in each of the motor oil ports each year and that pump will run indefinitely.

Note @mattmia2 's comment about the mounts.

It's a B&G 100. Still available today.

https://www.supplyhouse.com/Bell-Gossett-102214-1-6-HP-2-NFI-Circulator-Pump

Not a 100- this is that pump's predecessor. My 1940 Bell & Gossett Handbook says it's the model H2, since the pipe connections are 2-inch.

Given the size of that boiler, I'm thinking that circ might be oversized for that system. This can cause the water to short-circuit through the radiators, reducing efficiency. Here's an extreme case I found years ago:

https://www.heatinghelp.com/systems-help-center/adjusting-the-flow-rate-for-an-old-gravity-hot-water-system/

Do you know how many square feet of radiation is on your system?

Also, an old round boiler like that one is inherently inefficient. A combustion test would probably reveal an extremely high stack temperature.