Slant Fin LD-40 PZ, Riello 40 question

mpitt

Hi Guys, 

Just moved into a new 90 year old house up in Canada with a steam system. The furnace is old but working, but I'm preparing for the situation of replacement when it comes time.

It's a two pipe system with mostly fin style rads build into the wall to create "convection units". All are functioning and traps looks to be a mix of old and new. 

When we moved in the Honeywell cut in was set to 7psi and differential was 5psi. Where there was a call for heat, the system would just run continuous until thermostat call was met. It didn't seem ideal in my head. It also produced more sounds when the whole system shut off. 

I read more into low and slow setting, cut in set closer to 0.5-1 and differential closer to 1-2 but after setting it up that was the burned cycles 1.5 minutes on, 1 minute off. I'm guessing the system was oversized even from the start when. The house would have been single pane windows, very little insulation. Now that the home is much more energy efficient, I think the boiler might just be way to much and the radiators just won't condensate quick enough to run my system at that low of an operating pressure without short cycles... 

Anyone have any thoughts? 

2 story, 3000sqtf house in eastern Canada. Slant Fin LD-40 PZ (189 MBH gross output, 142 MBH steam vapour. 

Mike

neilc

post pictures and we'll nit pick, i mean educate you,
of the boiler, a shot or 2, floor to ceiling, showing the piping above,
also a closer shot of the Ptrol, sightglass, and low water cut off,
throw in your feeder also,
you're flushing the LWCO, and have serviced the pigtail ?
and picture of the convectors,
and find your main vents also,

EBEBRATT-Ed

Everything @neilc said + get the "square ft of steam" off the boiler name plate. And calculate the rating on all the convectors. We can help with that if you don't know how.

If everything is working the way it should you may need to increase the pressure slightly to cut down on the short cycling.

mpitt

mpitt

mpitt

I've set the cut in closer to 1 and the differential to 3 and it seems a bit better. After initial warm up, it now cycles 3 minutes on, 2 minutes off....ranging from 1psi to 4pri. 

I have blown it down. Drained sightglass, drained condensate tank and lines. Cleaned pigtail. 

Perhaps with this style of radiator it's more challenging? Ill Have to spend some time getting physical measurements. They are all built into the walls. The one rusty one was removed from kitchen after they removed and put in floor electrical radiant heat. 

There is a total of 12 radiators attached to the system of that sort. Fin style with three tubes. Most are closer to 24-30 inches wide. 

mpitt

There is no venting that I see. 

mpitt

All copper

mpitt

Anybody have any thoughts ? I'd love to know how to calculate the equivalent square footage required at you for the convector style radiators. I also just tested my low water cut off and it looks like it doesn't work we'll have to disassemble and clean.