Slightly OT:power vent for a boiler

They are a lousy option - fail on a regular basis, noisy. There have been two on the building I work in for the past 9 years or so, so I have some experience of them - these were installed when the heat was changed from electric to oil, and they were too cheap to put up a chimney or two. The oil burner service guys all seem to agree that they are highly inferior to a chimney. If your oil does the hot water as well as the heat, you also get oil fumes in the windows during the summer.

A few years ago, I went from a proper chimney to a powered vent out the side of the house. Allowed me to cap the chimeny and fix the leaking problem around it that had bee forming. I knocked the chimney down to flush with the attic floor and capped the hole.

The power vent is nice. Mine being off an LP boiler, on really cold days I get a buildup of ice/frost on the outside wall where it exits, it depends on the wind patterns. You, with an oil fired boiler, may have issues with carbon buildup.

My chimney was junk, so it was going to be expensive to replace. I went the cheap way out with the vent. I like my house, but hope to build a new one in the semi-near future so try to avoid spending money on it that I can't recoup in the future when it gets demolished.

JW

S'Okay, Been there, Done that - our double fireplace used brick & oval tile flue (rubble fill) chimney deconstructed itself in the 1994 Northridge Earthquake (but it stayed mostly together till we had a chance to rip it down to roof level). That was when we found out that the original builders seriously scrimped on the steel - we found several lengths of *used* 1/2 Gal Water Pipe as the reinforcement...

We took it all out, framed it in, and installed two steel-box fireplace units and steel triple-wall flues - even in Sunny Southern California you still want a source of emergency heat.

Quals: I have had installation and service training on *gas* appliance venting (Amerivent "B Vent" and the like), which isn't 100% applicable to oil fired due to the higher combustion temperatures, but close enough...

I would suggest a metal flue system of some sort - but you might be able to locate it in an existing interior wall chase (like where the furnace ducts go up to the second floor) or put a new chase in the back of your closets, and still put in your bay window where the masonry chimney used to be.

But consider the needs of having an emergency heat source in a few cords of wood out back - you might want to frame in where the old chimney was, and install modular steel firebox fireplaces in the same space, and you can snake a separate furnace flue up through the same chase. The fireplaces with the heat fans will put out a LOT of useful heat.

And if you put up stucco lath you can cement lightweight "cultured stone" to the outside to duplicate the looks of the old river rocks, and the casual observer will never know the difference - except for the sheet-metal rain cap with all the steel-flue draft caps on top. (But even that can be hidden behind a sheetmetal ring.)

A forced draft sidewall venting system is adding a lot of complexity and points of failure to your heating system, and KISS is always a safe bet. Especially when "something went wrong" means a fire.

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I have been running one of these (Field Controls)for 13 years without major problems however you do have to be careful of a few things:

1. The vent must be setup according to the manufacturers instructions....carefully. Post purge must be long enough.
2. The vent motor must be lubricated each year. Also the vent pipe should be cleaned at the same time.
3. The burner / boiler will behave differently than with a chimney. It should be setup carefully, especially regarding overfire draft.
4. The squirrel cage on mine eventually rusted out and needed to be replaced. .

Jim