Driving a cat- need more heat from an FPX44

[Got Wood]

I dont have a thermometer on mine so I cant answer your questions on temps. I gage by the heat output, when the fan kicks on and how long it stays on. Based on my experience (and I should say I am a rookie still) the efficiency is improved getting the Cat glowing then shutting the air down. Try it and see for your self.

 

[Todd]

Where are you taking these temps on your insert? Basicaly the cat will lite off when your fire reaches an internal temp of 500 or more, if your therm is on the outside it's probably double that on the inside. If you wait too long to engage you will lose much of the fuel the cat needs when you close the bypass to engage. Try this, start a fire with 2 small splits and a bunch of kindling on top, burn in bypass mode til it turns into a good hot bed of coals (about 30-45 min) then load her up full, continue to burn in the bypass mode for about 15 minutes and adjust the air so it's not raging but has good flames then close bypass to engage the cat, adjust your air til the flames start to slow down and seem toi lift off the logs. The temps should start to rise once the cat is lit. When reloading open bypass, rake the coals forward and load back to front, burn with full air til it takes off then turn it down some and wait 10-15 minutes before closing bypass to lite off the cat.

 

[[email protected]]

I am taking the temp on the very top corner of the door closest to the cat.
I also take the temp with the Ir gun.

How here is what I did last night and did notice a improvement.

first load maybe 6 splits and a ton of kindling full air 30 min in blower kicked in 45 min later coals and 350 deg.
I think my process on the first load hep it to heat up quick as not all the heat is going straight up the stack?? Will care about that later.
another 7-8 splits on coals full air 10-15 min full blast furnace engage cat temp still 350 10 min later cat glowing lower air to about 1/2 (450deg) 20 min later air down to 1/4 ( 450 deg)

 

[Got Wood]

It wasnt that cold here yesterday but I did have a fire to take the chill off. Having had this dialog I paid closer attention to the timings, here is what I did:
First load was kindling (scrap lumber which really helps get the temps up quick), small diameter rounds (like 1") and a couple bigger splits. Fire was roaring within 10 min, engaged Cat with full air. Cat glowing red within 5 min. Lowered air to about 1/3, 10 min later lowered to 2/3. Fan kicked on about 20 min after start up. Load burned pretty fast because of the nature of what I started with. Reloaded after 45min with normal size splits , full air and open bypass for 5 min - fire roaring again. Shut bypass, waited about 5 min to have Cat glowing red, then lowered air. At this point I just let the fire run its course as the house was getting too warm for my liking and we were heading for bed soon anyhow.

By no means am I saying this is the best approach, just what I did last night. Noting the difference to your approach being the timing between steps being longer for you. Perhaps try shortening the gaps and see what results you get. My thinking is the sooner you get to bypass shut, air down with Cat doing its job the more efficient(getting the most heat out of your fuel supply) you will be.

 

[youngstr]

Hey 44Elite,
I have a FPX 44 Elite as well. Some of the other members have nailed the air control thing. It's somewhat counter intuitive....you would expect more air=more heat but that is not really the case. I find that once a fire is established my optimum air setting is less than half of full air.

Once question I have is where is your blower air coming from? The basement/crawlspace/semi heated space or from the outside. I know that using outside air(the posi pressure) will significantly cool the firebox and may make it more difficult for you to reach the temperatures required to engage the CAT.

Y

 

[[email protected]]

I believe you may have hit the nail on the head youngstr.
A big blast Furnace fire looks hotter and feels hotter ( radiant heat to chest) but it's not hotter.
My blower air is pulling outside air.
I am going to change that to pull air from the basement. I believe that my configuartion of the p trap is no good (not enought P in the trap) as I can feel cold air and hear wind howling thru when not in use.

I know by doing this I will loose the possi pressure but my house is 2 tight any way with 2x 6 Closed Cell foam / Cullouse combo. I don't remember any more but i believe the walls are an r 30 and the roof is r 62.

 

[begreen]

Are there any appliances in the basement that need combustion air like a furnace/boiler, hw heater, gas dryer? If it has its own outside air probably no problem, but if not, you'll want to be careful not to reverse draft on that unit.

 

[youngstr]

Hey 44Elite,
I think that will definately help.

A few years back when we had ours put in the installer said that we needed to find a place inside to mount the blower. This really tweaked me since I had already cut and framed a square in the side of the house where I wanted the blower installed! I believe the most recent FPX install manual has a map that shows where they don't recommend using posi-pressure.....I can't remember if it was recommended for IL or not.

We have our blower in the basement which isn't too bad......I actually think it circulates the air to the basement keeping it warmer down there.......

Let us know how you make out!

Y

 

[Got Wood]

I pull in outside air, the pos pressure is good for me as I do have drafts that I am slowly working at improving. I have not noticed any issues with the P trap.

 

[youngstr]

Here is an excerpt from the install manual.....you guys in the white are lucky!

Y

 

[[email protected]]

Are there any appliances in the basement that need combustion air like a furnace/boiler, hw heater, gas dryer? If it has its own outside air probably no problem, but if not, you'll want to be careful not to reverse draft on that unit.

I do have an furnace and a water heater down there but my basement in just shy of 2000 sqft with 9ft ceiling. i don't believe this should be an issue.

 

[[email protected]]

I am in the white. But I am sw of Chicago and I don't care what the map says it's cold here sometimes

first I will just have to address the p trap issue.
Then test it out

If no help switch the blower to pull from the basement.
If you think about it the blower pulls cold air say 20 deg(or colder) then circulates it thru the insert to be heated then into the room.

You would have to think that using 65 deg air your blower air would then be hotter and you wold not be cooling off the insert. So it would not have to work so hard to heat the air.

If those 2 things don't work I am boing to stuff the chase with the 2 rolls of Ka wool I just got .

If that does not work i will run my 97 % eff Ng furnaces I spent big money on