I have a masonry chimney and a wood burning stove which I am removing to install vent free Gas logs. My question is I need to Block the Fireplace opening just above the logs where it starts to go up the Chimney, How is the best way to do that and what is the best thing to use to do it?

 

Just in case you were not aware, ventless appliances have been outlawed in many areas due to oxygen depletion, moisture, and CO dangers.
When you use your ventless logs, you’ll have to open windows and/or doors to the outside to allow air to be exchanged.

 

What is the shape of the opening you need to block off? I would think of using something like Hardie Backer. It's fireproof and easy to work with. The most difficult part will be cleaning the flue opening so you can get fireproof caulk to stick.

As for vent free gas logs. All modern gas logs have oxygen sensors that shut them down if the oxygen level in the room drops even slightly. I do recommend a carbon monoxide detector though. That's just good protection anytime you have a gas appliance, even those vented outside. As for the moisture that can be a good or bad thing. If you find your house gets dry in the winter or you run a humidifier then the water vapor put out by the gas logs can be a good thing. If your house is a modern, well insulated and super sealed home it could put too much moisture into the house so keep an eye on it.

 

I’ve seen those oxygen sensors not function at all.
One of my customers had such a bad experience the logs, which were LP, covered most of the house in black soot. And the oxygen sensor never shut down the gas valve. The fire department was dispatched to the house.
They should under no circumstance be trusted.

 

I'm not sure exactly the shape or anything until I get the Wood burning stove out which is going to take about 3 people, that thing will be Heavy! Then once that is out then I will know what it looks like in there.

 

We were thinking about just keeping that old wood burning stove, But we got to thinking about how much trouble it would be and our health is not in best shape to be splitting wood and what not.

 

You’d be better off with a vented insert.

 

Yeah and lose 80% of the heat up the Chimney? What good is it to even have one if you can't heat with it if power goes out?

 

See my previous post. While using them you’ll have to open some windows. They are not suitable for a primary heating source.

 

Just so you know our fireplace is NOT our primary heat source we have electric heat /AC. But if the power goes out in winter then the Fireplace is our only heat.

 

The only failure I have seen of a oxygen sensor causes the stove or gas logs to shut off. Their failure mode is to a safe condition (turn off the gas supply) and they are quite sensitive. So sensitive that a layer of dust or soot on the thermopile is enough to cause the stove or gas logs to not work.

A gas appliance producing soot has a problem not related to the oxygen sensor. A flame produces soot when the fuel air mixture is not correct and has little to nothing to do with the oxygen level in the room.

Oh, and the fire department will come any time they are called and for almost any reason. False alarm or not. I have had the fire department dispatched many times to my rental properties. Every time there is a funny smell some tenants call the fire department. The funniest (most pathetic) was a tenant who sprayed a whole can of oven cleaner in the oven and thought it magically made all the dirt disappear. She never cleaned or wiped out the oven. So, when she turned the oven on the cleaner covering the elements smoked... and the fire department came... and told her to read the instructions on the can... and clean the oven.

Keep in mind that gas stoves and ovens are used all over the world and they do NOT have oxygen sensors. It's the same fuel (natural gas or propane) being burned. If the flame or pilot goes out on a gas log set it automatically shuts off the gas. If the flame goes out on your stove top the gas keeps flowing. If the oxygen level in the room drops a gas stove/oven will keep on burning. A gas log set will turn itself off.

 

I'm not scared of a Gas log set not shutting down or what not because I know most will 100% of the time do so when oxygen Drops. My thing is I'm just trying to decide which is the best route to go and if we do go ventless what's the best and easiest way to close off the Flue. But to be honest I really would love to use this wood stove insert one season just to see but I'm afraid it would just be too much on me. I'd have to get a log splitter and buy a load of wood, plus have the chimney swept.

 

Does anyone know what kind of stove insert this is? Theres not a name on it, it has the double doors with handles at the Bottom, and it also has a Blower inside the right side with a Knob on the same side. It's going to be hard for me to get rid of this thing as it looks like one mean heater!

 

It's nothing like I've ever seen before. It almost looks custom built..... and it may be.

 

Yeah it very well could be. Anyway we have just made up our minds to pull it out and install the Gas Logs. Now just have to figure out best way to close off Flue once I get this thing pulled out.

 

I'm also going to have to run the Propane Gas pipe through the Masonry Fireplace. Not real sure how hard that is going to be, I guess it's just a Matter of Drilling through the mortar of the brick work.

 

I'm guessing you will have a sorta regular rectangular flue opening. If you're lucky it will be in a relatively flat plane. You might be able to drill into the brickwork to attach a piece of Hardie Backer right to the face over the opening. A thick bead of fireproof caulk or fiberglass insulation can seal it off and prevent drafts.

Harbor Freight has a pretty decent set of 12" long hammer drill bits. A 1" hold might be big enough for your gas line. Hopefully 12" will be long enough.

 

I actually thought about just covering the whole chimney opening at the bottom with sheet metal and then caulking around it with a fire proof caulk.

 

If I were to have a damper in my chimney, would I still have to close off the bottom with something?

 

I would seal off the opening. Dampers don't seal very well so you'll likely get a draft down the chimney. And a damper isn't insulated.

 

Just weighing all options here, if Power were to go out in winter and we had to use our logs for heat, Just how much space would "Vented" logs heat. I know they will not heat the whole house but more than likely neither would vent free.

 

It would depend on the size (BTU's) of the unit.

I installed a 35 kbtu natural gas sealed insert in my fireplace in my porch. It uses dual/concentric venting thru the old chimney flue. It has a thermostatically controlled electric blower in it. It heats the entire first floor of a split level home. It can run with no electricity but the blower wouldn't run as it needs power. I have a generator so it's not a problem but it's a nice backup heater.

 

The vented set I've been looking at is like 65,000 btu for LP.

 

We are about 95% sure we have our Minds made up on going with A Vented set of Logs. Our Chimney is already open as the damper has been removed because its missing. So nothing has to be done other than running the Propane Copper Gas line. We are not planning on heating the whole house with FP as we have central heat and air. So this should heat our Living room if need to and will give us the Real Fire effect and be much safer.