Narrowing The Field - RSF Opel 3

[begreen]

I just checked and you are correct on the central blower. The inline central blower FO-FDHB6-1 is rated to handle the heated air off of the fireplace. There are special temperature restrictions for the connecting ductwork. Installation instructions are here:
(broken link removed to http://www.icc-rsf.com/c/iccrsf/file_db/foyers_options.pdf/FO-FDHB6-1_2010-08.pdf)

What I am unclear on is whether one installs both the intake blower and central blower. I thought it was either or and that with the central blower that the intake was passive, but could easily be wrong. Let RSF be your final word here.

 

[Snakebit12]

I just checked and you are correct on the central blower. The inline central blower FO-FDHB6-1 is rated to handle the heated air off of the fireplace. There are special temperature restrictions for the connecting ductwork. Installation instructions are here:
(broken link removed to http://www.icc-rsf.com/c/iccrsf/file_db/foyers_options.pdf/FO-FDHB6-1_2010-08.pdf)

What I am unclear on is whether one installs both the intake blower and central blower. I thought it was either or and that with the central blower that the intake was passive, but could easily be wrong. Let RSF be your final word here.

Ahhhh - now I get your question.

I am 95% sure that the RSF tech support guy was aware that I was planning to combine the intake fan/blower and the central blower in my configuration. When they talked about the slightly lower airflow generated by the inline fan/blower versus the internal blower, that was in reference to hot air flowing out of the top louver. The intake blower (or the internal fan/blower for that matter) lacks the oomph to blow heated air through a central heating system. As you stated, only the central blower needs to handle heated air. I will have my rep confirm.

I'm glad that you included the central blower instructions. I noted that they had the central blower mounted at or above the fireplace where I plan to mount mine below the fireplace in the basement (for easier access). While it does not mention that you cannot mount it below, I need to have that configuration confirmed as well.

My rep is new to the RSF line so she is quite eager to follow-up on my inquiries...for our mutual benefit. I have a lot of confidence in her.

My HVAC guy stopped by today and advised against connecting to the existing zone heating system...concerns about dampers not opening as required. He also wanted to make sure that the central blower has a back draft control to keep heat from our heat pump from blowing back into the fireplace - the literature says that it does have that control.

He is on board with a dedicated duct - will quote me on that part of the install. Unlike RSF, he does believe that a 635 cfm blower could be run to more than just one dedicated duct.

I'll probably stick with my design...probably will install a thermostat for the central blower located in one of the remote rooms fed by the dedicated duct.

 

[Snakebit12]

1st installation quote received...$5.500 which is about 2 x what I expected.

So, I would be looking at:
Opel 3 $2,775
Options 1,585 (Gravity vent, damper, inline fan, Central heating blower, thermostat, OAK)
Excel Chimney (Dealer Est) 2,200
Labor 5,500

Total 12,060

This figure includes removal of old fireplace and chimney but doesn't include material/installation of dedicated duct nor masonry work to re-install facia removed during ZC removal.

I figure $13.0k - 13.5k whereas I was targeting $10k.

Does this seem reasonable?

 

[begreen]

Labor seems high even being generous with their wages and time. Let's say two workers @$100/hr each for 20hrs. That's $4000.

To get this down to a more reasonable cost I'd do the tearout myself and ask for a new estimate for just the install. That should be a day's labor.

 

[WiscoWoodman]

Labor very high. I had Rsf Opel 3 installed with gravity heat dump including removing old fireplace and 2.5 stories on chimney. My labor was less than $2k. Pretty sure the whole job was about $7500.

 

[WiscoWoodman]

A couple extra comments from my experience. My Opel 3 has a standard blower in addition to a heat dump blower. The standard blower is quiet and really does the job. However, the heat dump blower is loud... Powerful but loud. It's adjustable, but even turned down it's so loud we rarely use it and we don't really need it as air circulates well without in our house.

Don't know how you plan on using the thermostat, but if it is supposed to control the air into fireplace I have a hard time believing it will be worth the money or will do much for you. You'll be adjusting air manually to get it right almost guaranteed. On the other hand, if the thermostat merely closes a vent to another room when room gets hot, that makes sense. We could use that in our bedroom but with experience now not sure it would be any more convenient.

RSF Opel puts out great heat. We love it. My only complaint is the ash sucked into bottom louvre issue, which you have addressed.

 

[Got Wood]

A few years back I ripped out the old ZC and put in a FPX 44. The labor for the destruction part can be done with a couple guys and some planning (its heavy). With one friend we were able to get the old unit and steel chimney out of the house. Might save you some $$$ to do that part your self.

 

[Snakebit12]

A couple extra comments from my experience. My Opel 3 has a standard blower in addition to a heat dump blower. The standard blower is quiet and really does the job. However, the heat dump blower is loud... Powerful but loud. It's adjustable, but even turned down it's so loud we rarely use it and we don't really need it as air circulates well without in our house.

I suspect that the standard blower is the one located in the bottom back under the firebox - is that right? With our proposed configuration, we will not have that blower. I don't think that I will have the heat dump blower either - we are looking at an inline fan for the clean face air intake of room temperature air. Isn't the heat dump designed to push heated air downwards (like to a basement)?

I have not heard the inline fan (230 cfm) for the air intake - would be curious to know if it is quiet. On that same vein, I have not heard the central blower (635 cfm) in action to know how much noise it makes. We plan to locate that in the basement so any noise would be somewhat insulated.

I hate the thought of cutting options to offset the labor cost...this is what I get for moving to a rural area where I have a limited number of service providers. Two more quotes out - maybe one of them will be more reasonable.

 

[WiscoWoodman]

You are correct that standard fan is the one in the bottom back of unit. It works well if using the upper and lower louvers.

And I use the heat dump to take heat to the kitchen behind the fireplace. I wanted to ensure I got enough heat back there in case a gravity vent wasn't enough. But we rarely use it due to noise and the fact that it gets warm enough anyway without.

So if you are doing a no lower louvre, where does the air come from that will come in under the stove and circulate around the outside of the unit and out into rooms? Does it come in under on the side of fireplace?

 

[Snakebit12]

So if you are doing a no lower louvre, where does the air come from that will come in under the stove and circulate around the outside of the unit and out into rooms? Does it come in under on the side of fireplace?

The heating air (as opposed to the combustion air) will be pulled in via the clean face air intake - which effectively replaces the bottom louver. To help with circulation, the inline fan is installed inside the clean face air intake - which replaces the standard fan/internal blower.

The clean face intake (for heating air) connects on the bottom left side of the fireplace. The outside air kit (for combustion air) connects on the bottom right side of the fireplace.

And none of this will happen if I don't find a better labor quote!

 

[Dale Dermott]

... I always leave the bottom one ... so that you can change the fan when it fails in 3-5 years.

Bingo. My fan works after six years, but has developed a high pitched squeaky sound (bearings?). How do I replace it without removing the chimney and pulling it out? Or, suggestions on an alternative fan to blow the heat out? Thanks.

 

[Snakebit12]

OK - an update one month later.

While we still prefer the RSF Opel 3, we had a local FPX dealer come in and quote both the 36 and 44. The installed cost (including removal of the current pre-fab ZC fireplace and chimney) is less than $10k...which is a major improvement over where I was 30 days ago. The dealer also gave me a quote of $2k to install the Opel 3 if I chose to go that route.

We like the FPX. They allow terminations of the two cooling ducts in a ventilated attic which works well for us. We probably would have no problems going with the FPX line except for a couple of points:

1. We still would prefer an insulated chimney.
2. We cannot navigate connecting the blower to pull in outside air (and realize the "posi-pressure" effect). We considered putting the blower in the ventilated attic but there simply isn't enough room in the chase for the double-walled chimney, 2 cooling vents and the blower duct. The other option was dropping down into our walk-out basement. But fitting this around the existing duct work and i-beams in the basement has become a bit of a nightmare. So it appears that we would have to settle for an inside blower. Do any of the current FPX owners have this configuration? If so, are you satisfied?

The other option remains the Opel 3. We were never planning to use outside air for heating with the Opel so the blower location is not an issue. But it does need outside air for combustion. RSP does not allow the air inlet to terminate in an attic (ventilated or not) so, once again, we must drop down into the basement where we face the same obstacles as with the FPX.

One other RSF negative...the dealer for the Opel and the dealer for the FPX (who would install the Opel) don't have "a great relationship". Should there be an issue down the line, I wonder how effectively they would work together to get the problem resolved.

Thoughts?

 

[begreen]

Why would a competing dealer install his competition's unit? That sounds like a very awkward situation. Can the outside supply run in the joist space to the nearest exterior wall?

 

[Snakebit12]

Why would a competing dealer install his competition's unit? That sounds like a very awkward situation. Can the outside supply run in the joist space to the nearest exterior wall?

It may well be an awkward situation - one I will likely avoid. Maybe their summer log book is light right now?

I received another installer opinion today confirming what I had already begrudgingly accepted - the only way to run any outside air supply in this house is vertically through the chase. Cannot go sideways or down...only up.

With the FPX, while the two cooling ducts must draw in outside air, the blower (for heating) may be located to draw either inside or outside air. If there is room in the chase, I'll draw outside air through the ventilated attic. If not, I'll draw inside air somewhere in the house. FPX allows the cooling ducts and the outside air duct to terminate in the ventilated attic.

The chase is 22" x 22". The question is whether that it large enough (considering clearances) to house:

• 8" double-walled chimney (12" OD)
• (2) 7" cooling vents and
• 6" blower duct

The installer is very confident about fitting the chimney and the cooling ducts (although he did mention ovalizing the cooling ducts) - not so confident about including the the blower duct. On paper, I can make everything fit without too much trouble but nothing is ever as simple as it is on paper.

With the Opel, an outside air supply for combustion is mandatory. I was already planning to draw inside air from somewhere in the house. In this case, the chase would need to support:

• 7" Excel chimney (I assume 9" OD with insulation)
• 5" insulated aluminum flexible duct (9" OD with insulation)

It would certainly be easier to fit the Opel piping in the chase than the FPX. But as of now, RSF does not allow the outside air supply to vent in any attic, ventilated or not. I have asked the dealer to push back on RSF for "approval" to terminate the outside air supply in a well-ventilated attic. The installer sees absolutely no safety issues whatsoever in doing so - but will not do the installation that way unless RSF approves. I do not have high hopes for a special approval.

Just waiting to hear back from RSF...

Am I making too big of a deal in wanting to pull in outside air for heating? I have found several posts from people who heat inside air and they seem quite satisfied.

 

[begreen]

The Opel seems like a cleaner install. Why does the 5" line need 2" of insulation? I also don't see how it is going to be a major issue to run the 5" line through the basement to the nearest outside wall by the breakfast nook. This is a huge basement. It will barely be noticed.

 

[Mr_D]

The 5" line (combustion air duct) supplied with RSF fireplaces is insulated because the air coming in can be 0F (or colder) depending on the climate in your area. If it wasn't insulated that makes a heat loss into the chase and it can also build up considerable condensation as frost. Since the fireplace has almost no heat loss through the top or side panels they remain at ambient room temp except where the outside combustion air goes in. That area freezes in winter (see attached photo).

The frost buildup remains on the side of the fireplace until the fire dies out overnight. Then it all melts and runs on the floor of the chase. I only get about 1/3 cup of water in Wis weather per day (at 40% humidity room air) but it was enough that we redesigned the intake on my RSF Focus 320.

We swapped out the 5" flex for a custom assembled 4" smooth metal duct since that actually has more flow than the flex anyway. We ran that in a loop as a trap (as per RSF's suggestion to reduce the frost) and then insulated the pipes. When we were done the local installer said it's a work of art and the first one he's done that way. The loop limits cold air drafting a lot better than adding a low spot in the pipe that the install guide mentions and when the fireplace is on that gives the cold incoming air more time to warm up before it hits the sheet metal sides. This cuts down the frost buildup on the side of the stove by 60%.

Before I close up the walls I'll leave a small drip pan below where the air intake goes in as insurance to protect the drywall ceiling in the basement.

 

[begreen]

Sorry I was unclear. My question was more like, wouldn't 1" of insulation suffice?

 

[Mr_D]

Oh.... Go from 2" to 1" insulation. I think that would be fine. Naturally there would be more BTU loss from the cold air in the duct since R4 insulation isn't much but when the cold air is heading for the uninsulated metal side of a fireplace that tends to frost up then pre-warming the air is a good thing.

Of course... if he's tight on space he can gain more room by going with a 4" round metal duct instead of the 5" flex and have slightly more flow regardless.
I should note that more air flow isn't always what we need since the air damper on these can't be shut off completely. There is a section of the air path inside the damper that bypasses the air flow butterfly valve. So when you get a roaring fire going,,, it's going to just keep on roaring regardless of the damper position since it can't be shut down all the way. I don't prefer that at all but I suppose they designed it that way to meet some EPA regulation where the damper supplies a specified minimum air flow (to burn cleanly?) whether the user turns it down or not. you can see the air valve in this JPG.

 

[Snakebit12]

The Opel seems like a cleaner install. Why does the 5" line need 2" of insulation? I also don't see how it is going to be a major issue to run the 5" line through the basement to the nearest outside wall by the breakfast nook. This is a huge basement. It will barely be noticed.

The installation specs called for an insulated duct. The flexible insulated 5" duct at Home Depot had an OD of 9" so I assumed that was standard. it was R6 I think. R4 might have a 7" OD.

It is a huge basement. It would be nice if I could drop down into an empty joist space and then run through that joist space to the outside. No such luck.

First, the fireplace literally sits directly above a heat exchanger tied to a 5-zone heating system in the basement. There is duct work literally everywhere...and very few spots where I can even pop down into the basement.

Second, it is not clear from the floor plan but 90% of the basement is underground with no "outside wall". The only outside access is a wall "south" of the Sun Room in the floor plan.

Third, the joists run horizontally across the floor plan and I need to move quite a bit vertically. Running vertically crosses another batch of heating ducts and, more importantly, a large i-beam. I could run below the joists but would have to "snake" the duct back up and run through the joist at the i-beam before dropping back below the joists and continuing towards the outside wall.

FPX classified that "snaking bend" as one 90° turn where you are only allowed 2 90° turns. Therefore, FPX would not allow me to use the side blower hooks-ups as it would involve (3) 90° turns. One on the side of the fireplace to point the duct towards the basement, one in the basement to change to a horizontal run and a third to get over the i-beam.

So, they recommended using the bottom blower hook-up and come straight down...This would satisfy the 2 90° turn limit...one in the basement to change to a horizontal run and a second to get over the i-beam But the bottom blower hook-up sits smack dab 2 right on top of a 16" heating duct in the joists below. So, with the FPX, upwards is the only choice.

RSF does not stipulate a maximum number of 90° turns in their manual. I would need three to make the run as their outlet connects on the side. In theory, a 4" duct is used for runs under 25'; 5" for anything greater. RSF is OK with 3 90° turns on a 20' run - but recommended the larger 5" duct to compensate for the additional resistance from so many turns.

 

[Snakebit12]

After six months of research - and terrific feedback on this website - we decided to go with the FPX 44...to be installed the last week of July. The deciding factor for us was the ability to vent the cooling ducts and the blower in our ventilated attic where we will not hear the fan. We have a large house and I will be curious to see how much of it the 44 can heat.

I was able to secure a reasonable bid for removal of the old fireplace and installation of the new one by a certified chimney sweep company that will service our chimney going forward. My electrician will be wiring the blower switch to a circuit on our Generac whole house generator panel to ensure heat in case of a power outage (we are very rural).

Our living room will shortly look like a scene out of Dexter while the mason removes 50 sq ft of rock fascia to facilitate the removal/re-install. We have been told to expect a 50% loss of rock during removal due to breakage so I have put The Boss in charge of finding replacement fascia which matches the existing material. She'll get it done.


I'm sure that I will be back once I fire this baby up with questions...


Again, thanks to all for your feedback. I need to start finding some aged firewood!

 

[iron]

I'm sure that I will be back once I fire this baby up with questions...

any feedback from your first season of burning? how's the venting working out for you?

 

[Snakebit12]

As expected, the first season was a learning year...from loading the box to managing the air. We refined our techniques on the fly.

We blew through 2.5-3.0 cords and could have used more. The FPX44 is a beast - pumps out an enormous amount of heat...I would guess that we effectively heated 2,500-3,000 sq ft. 6-7 hour burns which we attribute to "less than ideal" firewood quality (wet). Hoping for longer burns with improved technique and improved wood quality.

The venting from the attic worked perfectly...that was a good call. There is a slight "hum" which is similar to the hum your hear from a forced air furnace. While barely audible, it is strangely comforting to hear as it means that "cheap" heat is being pushed into the house.

We had read that the ceiling fan should be set to pull air up. Tested both ways and there was no question that, at least in our house (cathedral ceiling), the heat disperses better when the ceiling fan is blowing down.

Wood heat is a different animal from forced air/heat pumps. Not sure how to describe it but it is just a very comfortable heat. Our humidifier got quite a workout.

While it would not be accurate to say that we are looking forward to this winter (we prefer Fall), it will be nice to fire this bad boy up again. I have 4+ cords that was split/stacked 16 months ago and another 4+ split/stacked this summer for next winter.

 

[begreen]

Thanks for the update!