Boiler Replacement, which one?

Dano_21

I have a 30 year old Utica, gas fired steam boiler, PEG112. It has 281 sq ft of net heating capacity (plus the standard 1.33). The top of the cast recently gave out, so it's time for a replacement.

Options I'm looking at are strictly Utica just to keep the piping setup (which works nicely). I could go with the same, upgraded boiler model, the PEG112EID, which brings the net to 292. Or go the next size up to the PEG150EID, which brings the net to 391. (basic differences is the cast iron on larger boiler has one more section and a bigger fire) I can accommodate either boiler both with space, gas capacity and exhaust.

My square feet of radiation currently measures 354. I'm thinking of adding another 40 with a radiator in a room that currently has electric baseboard. That would bring the net to 394 and seem to indicate the larger boiler.

There is a two-inch main that feeds most of the house with a 1-inch dry return. All the takeoffs to the radiators are 1 1/4". Any radiators on long runs (5 of them) have Gordon #1 vents before the radiator valve and are vented slowly through the radiator vents.

My boiler guy is telling me to go with the smaller unit, saying there might be a condensate return problem with the larger unit. It seems to me that the opposite would be true.

Thoughts?

And thanks in advance, this board (and Holohan's books) have been invaluable over the years keeping that 30 year old boiler working.

ethicalpaul

Your boiler guy is a rare gem with advice to stick with the smaller unit, keep that guy around! If I was for sure going to add the new radiator, I might go with the 150. Did your steam guy know that you were planning to add a new radiator when he said stick with the 112?

About the brand/design: I replaced an early 90s Utica PEG112 myself this year with a Peerless 63. It was going to be that or a WM. I'm very happy with the Peerless, but I'm sure the WM would have been fine too. I liked the apparently heavier cast of the Peerless, and its larger number of ports and its push-nipple construction.

BUT by far the biggest benefit, which will make me never recommend a Dunkirk design like the Utica, is the top side steam outlets vs side outlets on the Dunkirks. It is so much easier to have dry steam with a top outlet design IMO. See my video on this subject here: https://www.youtube.com/watch?v=4IymyZB4wlI

Dano_21

This is really inciteful. Thank you. What is the benefit of having two steam takeoffs from the boiler? I have just one now. I assume it's so more steam reaches the header faster.

ethicalpaul

It's actually the opposite. You want to keep the "velocity" of the steam lower so it doesn't carry water with it. Giving the steam two paths to travel cuts its speed roughly in half. It's plenty fast enough regardless.

I didn't need two on my boiler according to the manufacturer because I had the smallest boiler they make. In each boiler's installation manual, it states how many and what size are required but going bigger or more never hurts so lots of installers will do that to minimize the chance of carryover.

ethicalpaul

You can see amazingly great steam velocity tables by Ted Parreco here: https://heatinghelp.com/systems-help-center/category/rules-of-thumb

Dano_21

Also, @ethicalpaul your near boiler piping is really nicely done. So clean.

ethicalpaul

Thank you. All the credit belongs to the folks on this fine forum. In 2018 I knew nothing about steam and had never fitted a pipe.

nde

What is your latitude? 40 lat might be fine with smaller boiler than loaded edr but say 45 latitude I would go bigger to match edr esp if you are going to add radiation. Boiler ratings already include the 1.33 pickup even though not part of rating, that is boiler that says 500 steam ouput is intended for 500 edr load without needing pickup added.

Dano_21

nde said:

What is your latitude? 40 lat might be fine with smaller boiler than loaded edr but say 45 latitude I would go bigger to match edr esp if you are going to add radiation. Boiler ratings already include the 1.33 pickup even though not part of rating, that is boiler that says 500 steam ouput is intended for 500 edr load without needing pickup added.

I'm at 40 latitude

ethicalpaul

Well the latitude, size of house, number of windows, insulation condition, size of yard, attached garage, color of house don't matter to the size of the steam boiler. All that matters is the connected EDR.

nde

Right, but you undersize a boiler to edr by 25% in 45 latitude and it will most definitely matter. I would go to the larger size even at 40 lat if you plan to have approx 400sft edr.

ethicalpaul

I don't think I agree with your first sentence, but that's OK. But I do agree this one is right on the edge.

Dano_21

Ok, so given that the EDR falls between two boiler sizes, what are the pros/cons of going bigger/smaller?

kenlmad

Something else to consider in your search: Check your utility company or state's website to see if they offer a rebate for replacing your old steamer with a new one. I replaced my 35 yr old natural gas W-M with a Peerless Boiler (PB 63-04) back in 2016. The PB 63-04 met the minimum efficiency requirement to qualify for the $1900.00 rebate.

Overall, I am still extremely pleased with my PB boiler.