Venting options for boiler Direct or Not?

Hey Guys this is my 1st Post, great site.
Currently burning 40lbs a day in a Coabrookdale darby venting through the fireplace into 1 half of divied masonary chimney.

I'm looking at getting a Coal Stoker Boiler for my home, I like the Harman VF3000 and saw one in operation last week very nice!
Home is 5 years old 3400 sqft with additional 1000 sq ft basement finished off.

My question is regarding my venting options.
Can I convert my Gas boiler to a direct vent freeing up the chimney for the Coal Stoker?
I would like to add a Stoker boiler to my Gas Boiler and have the Gas boiler serve as a back up. Currently the Gas Boiler is venting into my chimney through cinderblock wall along with the gas hot water heater tee'd-in. The Gas boiler has an automatic valve closing the 6 inch flue when the boil is not fired. Not sure if that allow me to tee into the current flue, probally not right...what do you guys sugest??
Sorry for all the back ground info just want to be sure I covered it all.
Thanks

to the best of my knowledge. You CANNOT vent a coil boiler and a gas boiler into the same flu.

Fortunately in my setup, I have 2 flus in my basement.

Perhaps a quick call to whomever services your gas boiler could answer the direct vent option. I'm guessing you would need a power vent. My neighbor has a oil boiler with a power vent out the side of his house.

That would be a call to myself.
How does a power vent differ from a Direct Vent?
Thanks

Welcome to the forum!

The following is based on my experience with both: A direct vent pressurizes the flue and expels the products of combustion through the pipe at pressure higher than ambient. A power vent draws the flue gas out by creating an artificial draft, and also requires a barometric damper as part of the install.

I would recommend a power vent with the associated controls to perform a post purge to ensure all CO has been pulled out of the flue. I would also say that it isn't a good idea to have both vent into the same chimney even with the stack damper, and in fact violates NFPA regs and your local Authority having Jurisdiction (probably the fire marshal) will be able to answer for sure. Plus there is always what your insurance company has to say. Best thing is not to do it.

Power vents are usually available used on ebay or craigs list and would probably cost between $100 and $300 (with controls) for your needs.

Keep us posted on how you solve this situation.

Thanks for the fast replies. Fourm is great.
I figured venting two appliances into the same flue is a bad idea, even though the Harman VF3000 I saw had it set up this way. So the Power Vent would expell not into the chimeny but through the wall above the snow line. Would it be better to power vent the Gas boiler rather then the coal stoker? It seems that the gas could be shut down faster if the power vent failed, coal not so easy right?

Local/national NFPA Fire codes normally do not allow dissimilar fuels into the same chimney/pipe. I believe you can run the same type of fuel appliances into the same pipe/flue if hooked up and sized correctly. My sister has 2 furnances and hot water tank all hooked up to a 12" flue with the proper Y's and baro dampers, but all are Fuel Oil.

With the power vent on your gas boiler, you could have it wired in so it only ran when needed, therefore, it wouldn't need serviced as much and last a long time. You wouldn't need the Stainless impellers, so it might be a bit cheaper for natural gas application.

With burning the coal, accumulation of fly ash on the impellers could corrode it over time, and you have to clean it and service it every year. It would run 24/7 as long as you coal stove was running.

I agree with Dave, power vent the gas boiler, it won't be running once you get the Harman up and working. Plus the fly ash and requirement for Stainless makes it more work/$$ to power vent the Harman.

Ok So I could do something similar to this setup SWG Power Vent on a Keystoker except it wouldn't need to be as heavy duty SS made for coal.
http://nepacrossroads.com/download/file.php?id=3267&t=1

What sort of expense would this add to the project

Ok it's amazing what you find when you do a little research. Thanks Guys I think power venting the gas boiler\hot water heater as recomended is the best solution. Now I need a nice stoker boiler.
The Mannual show the install process and all clearances:
http://www.fieldcontrols.com/pdfs/46139100.PDF

Welcome to the Forum Coalbrookdale, where abouts are you from?

I have a VF3K, and lke it a lot. Its a very well made unit that should give you many years of service. There are lots of posts here on Harman, Keystoker, AHS, EFM and AA boilers, with lots of opinions and comparisons, so you can make as informed a decision as possible.

My gas boiler was by design a direct vent unit, as is my gas furnace. I would definately side wall vent the gas boiler, gas produces no visible smoke or soot unless its burning very poorly. The ventilator would only be needed when the burners are lit, and should actually run very infrequently.

The VF3K has a 7" flue, kind of an oddball size, so the flue pipe and chimney needs to be at least of the same size as this. IF yours is a masonary chimney, chances are its actually larger than this so you should have no problems here.

Good luck with your project.

A 6" flue will work fine for the VF3K. A solid fuel burning device cannot share a flue. Gas and oil can share a flue however. And you can have more than one gas device or oil device in one flue as long as the flue is sized to accomodate them.
As was already stated, you will not ned the gas boiler once the Harman is online.

Look over the specs for the power venter (link below) and location is the most important to make you decission. They have been used in tract housing for years to save the expense of chimneys. Placement is key other than that for your use in this case do not hesitate.
http://www.fieldcontrols.com/venting.php

Also, check out Tjerlund's ventors.

I'm in Slate Hill NY10973, just outside Middletown NY. 15 miles or so from Pennsylvania. Grew up in Michigan so I know cold winters, not that these New York winters are any warmer...

How little coal can the VF3K burn in the summer when used for domestic hot water.

Also what kind of clearance do I need in order to get it into my basement? I have Stairs coming down through Bil-Co doors and through a 36" wide door to the basement. If the unit comes apart in sections what weight of the heaviest sections.

The chimney is ridiculaous the builder was stone mason and went over board. Brick external chiney with two sections of tera-cota tiles I think 10"x12 and 10"x10" Draft is fantastic. Guess buring coal is my new hobby, this is my second season.
Thanks Guys!

The VF3K is a two piece boiler, when you take off all the sheetmetal and disconnect the water jacket from the base, its about 2' wide, so it should easily pass through any doorway. Its heavy though, the main section is probably about 800# so you'll need friends or a comealong. It is a reversible design so the flue can be either on the left or right side.
As far as coal useage goes, I burned about 12# per day during the summer for hot water, and it made plenty of it.

If your outside of Middletown NY, your not far from me. Where are you getting the boiler? Have you tried Gardens to Grow in Montague NJ? They are right next to Port Jervis, and not too far from you. Tom, the owner is a good guy, they don't keep the units in stock, but get deliveries from Harman fairly regularly.

As far as coal dealers go, there is one in Cornwall NY, but I have no direct experience with them, Ive tried contacting them, but they don't return emails.