What would you do with this setup?

[iluvjazznjava]

hello everyone,

Just bought a house a month ago that has a classic masonry style fireplace. It was inspected and is in good working condition with one caveat - the blower fan that blows through the opening above the mantle doesn't work. The house only has electric heat otherwise, so the plan is to burn a moderate amount of wood to help with heating. I am not interested in a new insert at this time (please don't suggest it). Here are my questions:

1. Anyone know how I can get a replacement blower fan for this custom looking setup?
2. There is a vent inside the fireplace (see pic) that goes down 4 or 5 feet. I think it goes down into the old fireplace in the basement, but I don't know for sure since it was sealed up. Is this supposed to some sort of air intake?
3. With a little more heat being the goal, I have been considering a grate heater. Anyone know one that would work well with my setup?

Thanks all ...

 

[iluvjazznjava]

Sorry, forgot the pics - here they are

 

[Jags]

For the fan - take a look at Grainger. They can match darn near anything, but they are not the cheapest on the market.

Good luck with your project. Open fireplaces are notoriously inefficient - sometimes even a negative percentage.

 

[iluvjazznjava]

Thanks I will try Grainger for the fan, I have one close by.

If I understand the way this setup is supposed to work, then the rising heat from the fire will heat the manifold-like radiator structure running through the flue. The blower fan then pulls in cool outside air, running it around the tubing where it is heated and then blown into the house. I will burn with the doors usually closed. There is a sliding vent below the doors to open to allow for some combustion air. I'm not going to pretend it's as efficient as one of the modern inserts, but especially with a working fan I have a hard time seeing this setup actually having a negative effect on my heating. I close the doors and the flue when not in use, limiting air escape. Am I missing something here, or do you really think using this fireplace isn't worth it from a heat perspective?

I lit a few fires over the past week, and even without the blower fan working the temperature in the room went up a couple degrees. This is my first fireplace - so I certainly appreciate help from those with more experience.

 

[Jags]

It depends. That is really all I can say. Much of the heat going up your chimney is conditioned air from the home. How much is really a guess. Where much of the heat loss comes from is waiting till the fire dies down to a level that you can safely close the flue. That time lapse of little heat from the fire to a dead fire (safe for closing) is the real bugger with all of the air going up the stack being "conditioned" air. A roughly accepted efficiency rating on fireplaces is anywhere from +15% to -10%. It is hard to nail these numbers down, but that is kind of a compilation of reports. A forced air fan is probably in your favor.

 

[mellow]

Does the fan have some sort of snap switch on it to shut it off when the fire dies down? Seems to me it would blow cold air if you let it run overnight.

 

[iluvjazznjava]

I agree that you don't want to let the fan run if the fire is out. The fan isn't wired at the moment and there isn't a switch. I tested the fan with my voltmeter and by connecting it to power and it doesn't work. The plan is to wire in a new fan (my Dad is an electrician, he will do the wiring) and to include a on/off switch and possibly a rheostat for variable fan speed. My "dream" setup would have a thermostat that would turn the fan on/off based on temperature, but that's probably more complexity than I want to mess with right now.

Makes me wonder if I should just grab one of those grate type heaters that have a blower and thermostat built in and forget the built in blower. Anyone have any experience with one of those?

 

[mellow]

You will have to have your doors open to run the grate heater tubing out, I think you would find it would be even worse heat output.

 

[Simonkenton]

That is an interesting set up. I wish I could see it in person. If it is drawing outside air in, and heating it, and blowing it into the house it is a poor design. You ought to drawing air from inside the house and heating it.
Is it possible that the outside air intake is for combustion air for the fireplace? Drawing outside air for burning a fireplace is always a good idea, because fireplaces use a lot of air, much much more than a wood stove.

 

[bholler]

That is pretty standard setup here for fireplaces built in the 60s and 70s and yes they usually have a net heat loss and occasionally a slight gain. And most of those grate heaters dont do much either the problem is that so much air is needed to make an open fireplace work even with the doors closed that more heated air is sucked out of the house than is made by the fire. You will feel warm in the room with the fireplace due to the radiant heat while the rest of the house gets cooler.

 

[iluvjazznjava]

Yes, I'm quite sure that the fan pulls air from outside the house and pushes it through and heats it. I tested it by taking a small tabletop fan that I had and mounted it in the fan opening and turing it on with the vent open. I could feel air blowing through into the house (although not very strong with my tiny fan).

The only other openings into the fireplace is the flue above, the glass doors in front, the sliding air intake opening right below the glass doors and that mysterious little trap door inside at the back of the fireplace (see pic) - still not really sure what that is for.

 

[bholler]

Oh that is outside i didnt look at the pics sorry. I have never seen that but I think that is probably not a good idea at all. But i might be wrong It might acctually add enough makeup air that it might help. You could try it but i think you will end up bricking up that hole

 

[Sprinter]

Well, you have the setup and the fan shouldn't be too expensive, so I'd say go for it and see. I had a manifold "heater" in a house in the 70's and it was way worse than nothing except for the occasional fire for ambiance. I always felt a cold draft near the fireplace. But maybe your setup will be better.

 

[bholler]

I agree with sprinter cant hurt to try but i would not go into it expecting much

 

[iluvjazznjava]

I am likely getting a new fan tomorrow - we will see what difference it makes. The fireplace never seems drafty. We will see if that holds as the weather gets colder. The doors seal pretty tight, as does the flue when not in use. I'm not asking for miracles here, but I would at least like to see a net heat gain from the setup.