New circulator pump install.

[Rockycmt]

First I want to thank this site. I am a prosumer. Very DIY and I got so much help here over the years. Now my questions.

1- My current circulator is not looking good. The flanges are not healthy. starting to corrode and look flakey. I want to replace. It is a Weil Mclain gas boiler hydronic system. I look below the current pump flange and it is cast iron to the boiler. Above is copper. I have no issues on the copper side. On the cast side I fear these joints are not going to easily unthread. What are the expectations here? Are the joints typically tuff enough to be undone? Or will this typically lead to horror stories. Any tips on undoing them?

Or maybe this is not cast iron pipe. maybe it is black pipe. how do i tell. It is threaded.

2- I am thinking of going with 0015e3-2F4 Taco Cast Iron ECM High Efficiency Circulator. Is this a good plan forward?

 

[Breplum]

I am a strictly California born/bred person, so I could be ignorant with my limited 50 years west coast knowledge; but, I am not aware of threaded cast iron pipe existing. So, in my albeit, limited knowledge, it would be black Sch. 40 pipe.
Of course Murphy's law and all its vast corollarys apply.
I have heard (maybe just legend) that when steamfitters had a tight cast iron fitting that they didn't want to struggle with, they hit it with a maul to crack it apart. Do not attempt this at home.
With clear working range and big enough wrench (cheaters if appropriate) all threaded joints will disassemble...as to the viability of the threads, who knows.
I am of the opinion that spray 'thread loosening', 'pipe break' even 'catalyst' products will not do you much good, compared to a properly sized wrench.
Heat from a torch can help.
See the test: or search Which Penetrating Oil is Best?

Though this is for small nut/bolt, not big threaded joints.
Good luck. no comment on the pump

 

[Sponsor]

 

[Fitter30]

Take a pic of the pump , pump name tag and flange.

 

[John Gayewski]

I run into cast iron fittings from the early 1900s sometimes. They usually come apart. The bigger the pipe the the bigger the wrench needed. An 18" and 24"wrench will get almost anything undone. Occasionally one will need a cheater bar. Be prepared to possibly crush the area the wrench contacts which will require a new nipple. This can happen if it's really hard to undo.

 

[Rockycmt]

Take a pic of the pump , pump name tag and flange.

 

[Fitter30]

I am a strictly California born/bred person, so I could be ignorant with my limited 50 years west coast knowledge; but, I am not aware of threaded cast iron pipe existing. So, in my albeit, limited knowledge, it would be black Sch. 40 pipe.
Of course Murphy's law and all its vast corollarys apply.
I have heard (maybe just legend) that when steamfitters had a tight cast iron fitting that they didn't want to struggle with, they hit it with a maul to crack it apart. Do not attempt this at home.
With clear working range and big enough wrench (cheaters if appropriate) all threaded joints will disassemble...as to the viability of the threads, who knows.
I am of the opinion that spray 'thread loosening', 'pipe break' even 'catalyst' products will not do you much good, compared to a properly sized wrench.
Heat from a torch can help.
See the test: or search Which Penetrating Oil is Best?

Though this is for small nut/bolt, not big threaded joints.
Good luck. no comment on the pump

Torch. Airokroil is my go to. Hacksaw or saw all the nuts off. Wire brush the threads use penitent ,6 point socket and some heat on the nuts. Gasket looks 1/8" red rubber probably made on site normally they use flat round gasket. What water temp are you running there should be all that flaky corrosion? Take a pic the boiler and piping stand back a little.