Flange leak from Grundfos record pump

[n6ac]

Hello – We have had our house re-piped, and the record pump was connected in a new configuration.
The pump is a Grundfos UP 14-42 SF (bronze, which has disappeared from the Grundfos catalog)

Unfortunately, it is now leaking from the output flange (arrow).



I am confused in searching for gaskets, as to whether it needs flat flange gaskets (like Amazon B07G8NWMB5)

or (rectangular cross-section) o-rings.

Can someone illuminate me please?
Or must I go ahead and disassemble to see what's what ...

And if it is the o-ring, what are the dimensions?

 

[breplum]

Rectangular Grundfos pump gasket for UP 15-42
Find at local plumbing shops.
We ALWAYS put isolation valves and purge hose bibbs on both sides of pumps. Makes changing and swapping soooooooooo easy.

 

[n6ac]

You mean the o-ring?
Happen to know correct part number?
Agree completely on the valves, they are in.

 

[n6ac]

The old pump has the flat gaskets! No groove. Hope the ones I ordered – arrive tomorrow – will be right fit. I will buy new SS bolts & nuts today to replace the rusty old ones. Wondering if it needs any type of sealant?

 

[n6ac]

Oh shucks, Amazon B07G8NWMB5 hole is too big and does not seal ... so much for "universal" gasket ...

 

[havasu]

My honest opinion would be to cut that old pump out and solder some threaded pipe to accept a new Grundfos pump.