Steel vs Cast

[derves33]

I'm not in the trade but looking for information.
20 year old slantfin oil burner bit the dust at the domestic coil.
I've had two quotes to replace the boiler with Columbia boilers which appear to be the local choice.

My oil delivery and service agremment company quoted me the Steel EM125
A business relationship quoted me the CSFH4 cast model for $1000 less.

Like the relationship with my oil provider, but it still a grand.

Regardless is steel or cast the preferred.

[jerryd_2008]

I'm a HO and don't know much about oil. Exact same capacity for apples-to-apples comparison? Isn't the heating season yet, unless you use for hot water, say, why not get some more proposals even on the exact same equipment, to see if the current ones are in the ball park?

[KevinCorr]

Steel and cast iron are used for different reasons and each has advantages.
Both can be long lasting and durable if applied properly, but each can be degraded by poor installation.

Steel boilers are great for cold start system. As a former dealer of Energy Kinetics Sys 2000 I have a lot of experience with that. See the website to understand their technique. I have used Laars Max 75 and light weight Burnhams in the same way. These are able to sit at room temp and fire on demand and come up to temp in 1.2 to 2 minutes. They run hot to avoid condensation. The efficiency comes from leaving them off like a hot air furnace works.
The are ruined by running at lower temps and allowed to condense.

Cast Iron can tolerate the cooler temps so they are better for modulating boilers. The German Buderus is one of the best and most expensive example of this type. The Burnham MPO, Slant Fin Eutetcic are others in the heavy modulating type. This type is now often controlled with an outdoor reset such as Tecmar or the built in brand electronics such as Buderus and Viessmann offer.

The old style cast iron ones that are not designed to modulate are obsolete imho. You couldn't pay me enough to own one.

Another new efficient type is the condensing boiler. There are some oil fired ones but they are more prevelant as gas burners. There are many good ones.

[KevinCorr]

I just went to the Columbia website and saw the Low Mass Boiler. It does not say it is steel but at 300 lb I am sure it is. They don't explain as the Sys 2000 site does, but if it is indeed steel it could be used as a cold start system. The difference with such a system as I have set up with Laars, Burnham etc is that you don't have the built in cool down cycle of the "System Manager".

I would prefer this boiler if it can be set up as cold start to a heavy cast one that was not set up as a modulating temp boiler.