Welcome! Here are the website rules, as well as some tips for using this forum.
If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Boiler choices and sizing.
House is 1950's build, open floor plan. Half brick, low pitch roof with no attic. 2/3rds crawl space and 1/3 slab. All windows replaced 2016 – double pane low E, high quality vinyl. New roof (2017) w/1-1/2” insulation board (this really tightened up the house).
132' of BaseRay cast iron base board radiators. These seem smaller than the 9A model, only about 6-3/4” tall. One BaseRay slenderized radiator 5 tube, 1-3/4”ctc, 25” tall with 14 sections in kitchen and one BaseRay slenderized radiator 6 tube, 1-3/4”ctc, 32 tall with 6 sections in the utility room.
Currently have a 25-some year old Lochinvar RBN 135. I don't know what the Lochinvar replaced but I remember it had to broken up into pieces (gigantic cast iron) to get it out of the utility room.
My own boiler sizing by the radiation method says I need about 55.5MBH.
The Slantfin contractor by manual J method says I need 53982MBH.
The Weil-Mclain contractor says by manual J (different software, I asked) that I need 57556.
I believe both of them. Pricing is similar for both.
Which boiler will be the most reliable for the next 10 years?
Gas fired, chimney vented SlantFin Sentry S-90?
Gas fired, chimney vented Weil-Mclain Cga4?