Enviro Empress FI - OAK mod experiment.

[phil san]

Installed an Empress FI two seasons ago. Found it was a tad noisy for my liking and the heat output was not all that great. ( have a block off plate and flex chimmney liner ). Last season I pulled it out, lined 3 sides and blockoff of the fireplace brick with 4" of fireproof rockwool sheets. Inserted 4" on the sides behind the surround trim plate and intake vents. OAK is from the existing FP ash dump ( no connection to total outside air - just left open as is).
What a differance. Very quiet and the heat output was greately increased. I like the idea of building up positive pressure within the house so I won't sway from that.

Trouble is, I'm fine up to and including level 3 burn. Any higher and I lack sufficient air i.e. lazy flame, pellet pot build up. So I'm thinking of cutting a 3" hole in the direct back of the FP brick hoping that will make up for air intake. I'll still have the quiet factor, should be no heat loss from within the house as the front surround will still have 4" of insulation. I'm going to try this no matter because the initial results were so, so good, I just need more air. BUT ??????????

There are 2 motors. The combustion is using the outside air and is not the blower motor doing the same? So where I was heating semi pre heated air and blowing into the room , I'm now
heating much colder air for the circulator. Just thinking if this is defeating the purpose or negligable.

Had to do it over, I'd get an insert made for an OAK.

ps
easier to cut a vent hole in the brick and damper it as some have run a flex pike for OAK down through the FP ash dump.

any toughts?

 

[WoodPorn]

Your combustion blower should be using outside air and your convection blower should be recycling room air

Maybe try opening up the ash hatch in the basement for more air?

 

[vvvv]

u have exposed insulation to absorb the noise & keep the heat from absorbing into the masonry?= good. i dont get how u constricted the combustion air

 

[phil san]

Seems the combustion air got resticted because of the insulation and closing up the firebox space. Only so much air getting in. If I pull out a a 3" opening of surround insulation I'm all set, but then that reverts back to using room air. I tried opening the ash hatch in the basement but didn't do anything. So I definately need a direct outside source but back to the original ? The convection and combustion blowers are on opposirte sides of the FI. Maybe if I stuff insulation at the 1/2 way point, the OAK air will feed the combustion motor and the inside air will go to the blower.

Last years set up made a super improvement, I now just want to get it so I can burn at level 4 and keep positive pressure.

 

[vvvv]

Seems the combustion air got resticted because of the insulation and closing up the firebox space. Only so much air getting in. If I pull out a a 3" opening of surround insulation I'm all set, but then that reverts back to using room air. I tried opening the ash hatch in the basement but didn't do anything. So I definately need a direct outside source but back to the original ? The convection and combustion blowers are on opposirte sides of the FI. Maybe if I stuff insulation at the 1/2 way point, the OAK air will feed the combustion motor and the inside air will go to the blower.

Last years set up made a super improvement, I now just want to get it so I can burn at level 4 and keep positive pressure.

positive pressurre will result in pushing warm air into walls & ceiling. why do u want it?

 

[phil san]

That's an age old debate no one will ever agree on. The positive set up works for me. Instead of using heated room warm air for combustion, blowing it out the chimney and thus causing cold air to be sucked in from walls and cracks to replace it: I'll use the OAK and get better heat in my particular setup.

 

[vvvv]

ok but FYI= when the wind blows in winter from the N, The exterior of the N side of the house gets pressurized & the S side gets depressurized which will blow thru the house unless the house is perfectly sealed or made of glass. EPA recommends fresh air, to breathe indoor healthily,at a rate of full volumetric displacement every 3 hrs. im not telling u what to do im just relaying what ive read. & your stove/ insulation cave makes sense.

 

[phil san]

Been burning wood for decades. 3 yrs ago when the oil sky rocketed I bought a pellet FI. New nothing of them except for research on this forum which I have read for years and years. 2500 sq ft 2 level home/ open plan.
Den area heats with a small wood burner. Main part is the Enviro. When I first installed I was very disapointed. Lousy pelletts but more so poor heat, drafts and poor heat again. Installed a BIG E in the basement to heat my
shop space on demand with an OAK and it's fine. Did the insulation retro on the FI last year and was able to heat about an 1800 sq foot section of the house on 2 or 3 with no issue. Used not 1 drop of heating oil.
The stove was like night and day. I just need more air for a #3 or #5 burn if I want it. I can do it now, I would just have to move some behind the surround insulation and then be using room air. Look; with opening doors, house condition etc., I have enough air circulating. Sleep with the bedroom window open a crack even in winter.
I'm just trying to figure is the outside air drawn through the blower circulator being very cold wasting energy. It does NOT seem to be the case with my BIG E.

 

[smwilliamson]

Installed an Empress FI two seasons ago. Found it was a tad noisy for my liking and the heat output was not all that great. ( have a block off plate and flex chimmney liner ). Last season I pulled it out, lined 3 sides and blockoff of the fireplace brick with 4" of fireproof rockwool sheets. Inserted 4" on the sides behind the surround trim plate and intake vents. OAK is from the existing FP ash dump ( no connection to total outside air - just left open as is).
What a differance. Very quiet and the heat output was greately increased. I like the idea of building up positive pressure within the house so I won't sway from that.

Trouble is, I'm fine up to and including level 3 burn. Any higher and I lack sufficient air i.e. lazy flame, pellet pot build up. So I'm thinking of cutting a 3" hole in the direct back of the FP brick hoping that will make up for air intake. I'll still have the quiet factor, should be no heat loss from within the house as the front surround will still have 4" of insulation. I'm going to try this no matter because the initial results were so, so good, I just need more air. BUT ??????????

There are 2 motors. The combustion is using the outside air and is not the blower motor doing the same? So where I was heating semi pre heated air and blowing into the room , I'm now
heating much colder air for the circulator. Just thinking if this is defeating the purpose or negligable.

Had to do it over, I'd get an insert made for an OAK.

ps
easier to cut a vent hole in the brick and damper it as some have run a flex pike for OAK down through the FP ash dump.

any toughts?

What is the diameter of your liner and how high up does it exhaust? For example: if you are running a 3" liner up 25 ft you will be creating too much back pressure on the stove resulting in poor burning on higher heat settings.

 

[phil san]

4" liner going up 16". As I said on the higher heat setting 4-5 only the flame gets lazy. Now here is the point. The Enviro gets its air from the 3"x2" vent screens at the top of the unit and from the bottom as it's 1/2" off the floor. This air is directed back behind the hopper to the blowers. I have those intake areas BLOCKED with insulation and only air coming in is from underneath the stove ( 1/2" space) from the open ash dump. " If I remove the vent insulation and run the stove as it was meant to be run, I can burn on the highest settings.
But again I'm using room air and it just does not cut it.

 

[smwilliamson]

Sorry, I misunderstood. How about if you cut the insulation away from those openings and leave it everywhere else. You still the sound dampening and airflow.

 

[phil san]

Yeah,but again if I clear the vents I use room air. Guess I'm just trying to find an engineering answer " am I wasting sufficient energy heating colder OAK for the circulator or not". Just have to try it and see.

 

[smwilliamson]

Yeah,but again if I clear the vents I use room air. Guess I'm just trying to find an engineering answer " am I wasting sufficient energy heating colder OAK for the circulator or not". Just have to try it and see.

I wonder if you're going to create a problem throwing frigid winter air over the back of the heat exchanger when it's piping hot.

 

[phil san]

Thought of that also. Plus the moisture content of the air leading to issues with the motors. I'm going to friggin do it anyways and see what happens. Like I said 10 times, level 1 - 3 were a significant improvement using the insulation and air via the cleanout.

 

[Delta-T]

can I assume that you have tried monkeying with the damper setting at the higher levels? Could be that the damper setting is limiting your combustion air (along with the insulation and whatnot) and opening the damper up on the higher settings might allow for increased flow from the sources you are currently using. I've been trying to decipher how the air intake works on the empress ins. from the explosion diagram, but I'm not seeing anything useful. ALso, you could maybe increase the airspace under the unit by cranking out the leveling bolt on the bottom of the chassis to give you maybe 3/4 inch under the unit?

 

[phil san]

I do have a Magahalec Guage or however you spell it. Yes on 4 and 5 I can open the damper full and not a significant improvement. Tried the airspace under bu 1" - not enough coming in frime the ash dump bottom of chimney.
The chimneysupport underthe brick where the ash dum pleads into is 12" poured concrete, so I doubt much air will flow in as I have tried it with the basement cleanout open. Before I cut brick I may just this week run some extra lex pipe through the basement cleanout up to the opening right behind and under the stove. I can't figure the empress either but it appears that the intake motor just pulls in air from it's plain surroundings and thats why the FI has small
vents at the top to allow room air in for operation.

 

[vvvv]

simply cracking a window when stove is running & watching the flame should tell u if u need an OAK or not, ithinx. any stove except Europa has so much excess combustion air that choking an OAK might make no diff, except soot & more efficient heating of the room

 

[phil san]

You all don't get it. "I'm not explaining right". I've sealed off the FI from drawing in any room air. This leaves me with circulator and combustion motors to draw from inside the firebox only with an ash dump opening that seems not to give enough air intake on setting #4 and #5. Well, I did it today and it works Not too hot out,so I went ahead. Hammer drilled an app 2 1/2" opening from outside brick into firebox opening. Put a plug of insulation in it so as to not draw air. On #4 flame gets lazy. Pulled plug and works like a charm.
Now I can use outside air and maintain positive pressure. After I play around I'll put some type of vent/cap on it and use a pipe to reinforce the opening structuraly. Figure I want to close it up for the summer months so as not to draw condensation into the rear motors.
Again, 3 yrs ago when I first became interested in pelletts, I was concerned about an OAK. Dealers told me not to worry. Again, if I had to do it again and I may go next year with the new enviro M55 FI that draws from outside.

But it works. I hope the motors don't get messed uo with condensation but burning 24/7 should eliminate that.