PSG Caddy please help!

NH_burner

New Member
Dec 4, 2019
58
NH
Gonna be tough to get secondary burn running wood that wet.
So if you pile up 100 lbs of wood, 29% of that is water...or, by weight, almost 4 gallons! (8.34 per)
Yeah, I don't plan on burning much of it. I just wanted to get a few practice fires in before the end of the heating season.

Do you have a window downstairs you can open to provide some outside air? Just to see if that changes anything.
Yes, I keep the closest window open and for most of the day I had the bulkhead open, too.
 

wooddope

Member
Mar 16, 2010
168
southern nh
The air you're feeling coming out the front is probably due the gaps in the outer jacket around the door and air intake. I had a similar issue with mine and used high temp rtv to seal it up. It was leaking enough to blow the ashes on the tray below the door around.
 
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NH_burner

New Member
Dec 4, 2019
58
NH
The air you're feeling coming out the front is probably due the gaps in the outer jacket around the door and air intake. I had a similar issue with mine and used high temp rtv to seal it up. It was leaking enough to blow the ashes on the tray below the door around.
I'm pretty certain that it's not that. It's too much air to be coming from such a small gap. That did cross my mind though so I moved my hands around and I'd say I'm 99% sure it's coming right out of the intakes. I'll try to get a video of it later on when I'm home just using incense or a lighter or something.
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,362
Wisconsin Dells, WI
I'm pretty certain that it's not that. It's too much air to be coming from such a small gap. That did cross my mind though so I moved my hands around and I'd say I'm 99% sure it's coming right out of the intakes. I'll try to get a video of it later on when I'm home just using incense or a lighter or something.
Is it still affecting the fire inside the firebox and blowing smoke out the intakes? I'd think if it was pressurizing the firebox like that you'd be filling the basement with smoke pretty fast and the fire would change.
 
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NaturalCauses

Member
Oct 3, 2016
46
Grand Rapids, MI
I'm pretty certain that it's not that. It's too much air to be coming from such a small gap. That did cross my mind though so I moved my hands around and I'd say I'm 99% sure it's coming right out of the intakes. I'll try to get a video of it later on when I'm home just using incense or a lighter or something.
With the stove cold and the door/intake closed, could you remove the stove pipe from the back and turn the blower on? If it were pressurizing the firebox then you should be able to feel the air exiting the back of the stove.
 

NH_burner

New Member
Dec 4, 2019
58
NH
Is it still affecting the fire inside the firebox and blowing smoke out the intakes? I'd think if it was pressurizing the firebox like that you'd be filling the basement with smoke pretty fast and the fire would change.
It does still have some affect on the fire inside the box but not blowing smoke out the intakes. When it was doing that I also had the chimney issue. I agree you'd think that it would be sending some smoke into the basement. My only thought is that the chimney is pulling enough that the blower is pushing smoke up the chimney and hot air out the intake.

I should add that the air coming out of the secondary air intakes is much cooler than the air coming out of the primary air intakes. This leads me to believe that the cold return air is making its way into the secondary air passage where it is then splitting off, sending some cool air directly out of the intake and sending the rest of the air into the firebox and forcing hot air out of the primary air intake. That's the only explanation I have for the difference in temperature of the air coming out of the secondary and primary intakes. Also, the air blows harder out of the left side secondary intake, suggesting that the issue is closer to that intake.

With the stove cold and the door/intake closed, could you remove the stove pipe from the back and turn the blower on? If it were pressurizing the firebox then you should be able to feel the air exiting the back of the stove
I'll be sure to try that as well when I'm troubleshooting later on.
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,816
NE Ohio
I should add that the air coming out of the secondary air intakes is much cooler than the air coming out of the primary air intakes.
Secondary air path is very long...primary air path is very short...
 

NH_burner

New Member
Dec 4, 2019
58
NH
AHA! It's much easier to feel around for air leakage on a cold stove! The GREAT news is that my firebox is not compromised and everything is good, the bad news is that many of you tried to tell me where the air was coming from and I just didn't get it :(. When you guys suggested it was leaking from the air jacket, I thought you meant from where the green front panel attaches. I did not realize it could be leaking from the gap directly around the door, intake, ash tray, etc. See attached pics. Is it common for the gaps to be that large? The air blows out of them with such velocity that there's no way incoming air is flowing in past the exiting air and making its way into the intakes. That is why I was seeing my fire go out and smoke come out of the intake when I also had the chimney drafting problem. I wanted a video to show how much air is coming out of the gaps but it just blew out any flame and made incense smoke disappear instantly.

FYI, a couple things I did to troubleshoot. With the blower on, pulled off the flue and did not feel any air coming out of the furnace flue. This was also confirmed by the Dwyer mano not showing any pressure changes with the blower on or off. Also lit 4-5 incense sticks inside the firebox and closed the door. If the blower was pumping air into the firebox the smoke would have been blowing every which way, but it was rather calm and slowly made it's way toward the intake (cold chimney puts a slight positive pressure in the box).

The next step is to seal up the gaps. Will the stove get too hot if I seal all of the gaps? Or should I just seal up the ones around the intakes?

The manual requires a minimum duct pressure of 0.2" WC and a maximum of 0.6". I measured mine yesterday at 0.65" with what seemed to be original filters and 0.7" with brand new filters. I know it's higher than recommended but is that a big issue? In theory, it will go up a little when I seal up the stove. I have 3 more floor vents in the second floor that I can open. I could also add an opening to heat the basement, but is the heat loss worth the pressure reduction? This is all with the fan on low.

Thanks again for all the help and advice!
 

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JRHAWK9

Minister of Fire
Jan 8, 2014
1,362
Wisconsin Dells, WI
IMO, that's some pretty darn high SP!! This would also contribute to the excess air being pushed out those small gaps. If you had lower SP (like in the 0.2" range) you'd see a lot less air escaping through those gaps.

Are all your vents open?
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,816
NE Ohio
IMO, that's some pretty darn high SP!! This would also contribute to the excess air being pushed out those small gaps. If you had lower SP (like in the 0.2" range) you'd see a lot less air escaping through those gaps.

Are all your vents open?
Agreed...0.6" doesn't sound right at all...
 

sloeffle

Minister of Fire
Mar 1, 2012
668
Central Ohio
The next step is to seal up the gaps. Will the stove get too hot if I seal all of the gaps? Or should I just seal up the ones around the intakes?
I have same furnace ( older green model ) that you do and I have zero issues with excessive air coming out through the gaps. My duct pressure is a little over 0.2 though. I'm with @JRHAWK9, I think your high duct pressure is causing some of your issues.

It is hard to tell from your pics, how large is your return air duct ? @brenndatomu please correct me if I am wrong, but I believe your return duct should be sized larger than your trunk line coming out of the furnace. You could take the back cover off of the furnace and run the blower and see if you have the same issue with excess air blowing out of the front.
 
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brenndatomu

Minister of Fire
Aug 21, 2013
4,816
NE Ohio
but I believe your return duct should be sized larger than your trunk line coming out of the furnace.
Yes, at least 10% larger
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,816
NE Ohio
The next step is to seal up the gaps. Will the stove get too hot if I seal all of the gaps?
Get your SP down first...I'd hesitate to plug those gaps since they look intentional...I always wondered if that wasn't the big difference in why the Tundra 1 cracked and the Caddys never did...Tundra doesn't have that "air cooled" front like the Caddys do.
 

SpaceBus

Minister of Fire
Nov 18, 2018
3,911
Downeast Maine
Is it still affecting the fire inside the firebox and blowing smoke out the intakes? I'd think if it was pressurizing the firebox like that you'd be filling the basement with smoke pretty fast and the fire would change.
This is my thought as well. If there was a fire in the box and air coming out of the intakes then the chimney is now acting backwards. Pretty much impossible to have a fire in the box and no smoke in the house if the air is coming out of the intakes.

Edit: I replied before reading, I see this part has been figured out.
 

NH_burner

New Member
Dec 4, 2019
58
NH
Are all your vents open?
All the first floor vents are open. I also ran 3 small vents to the second floor that are closed because the space is currently unfinished. I'll try opening them and see how it changes.

Get your SP down first...I'd hesitate to plug those gaps since they look intentional...
Good point.

Yes, at least 10% larger
I doubt return air restriction is the problem since a larger return would only increase pressure on the feed side, right?

In any case, the hot air plenum is the full size of the opening (see my original pics in the first post) but it reduces down to (IIRC) an 8x18 trunk. All of the branches off of that are either 6" or 8" round flexible duct. I'll have to measure when I'm home but they're all insulated so tough to tell. There are 7 of those that I can think of. And then 3 additional 7 or 8" oval ducts going to the second floor that are currently closed.

Open concept house so there is a single return air duct that is probably 14x24 but that is converted to a round duct probably 14 or 16" in diameter before connecting to the return air plenum. That can be seen in the original pics as well.
 

NH_burner

New Member
Dec 4, 2019
58
NH
I didn't really pay much attention to it at the time since I'm not an HVAC guy, but I'm thinking the round flex duct may be a big contributor to the static pressure. Since it isn't smooth and can be easily restricted around bends and what not.
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,816
NE Ohio
I didn't really pay much attention to it at the time since I'm not an HVAC guy, but I'm thinking the round flex duct may be a big contributor to the static pressure. Since it isn't smooth and can be easily restricted around bends and what not.
Thats on the supply side?
If so, flex is not recommended for wood heaters...not rated for high enough temperature, and the flow characteristics on it is terrible...flows "much smaller" than its nominal size...
 

NH_burner

New Member
Dec 4, 2019
58
NH
Thats on the supply side?
If so, flex is not recommended for wood heaters...not rated for high enough temperature, and the flow characteristics on it is terrible...flows "much smaller" than its nominal size...
Yep, that's on the supply side. Kind of stuck with it now. I'll take some pictures later.

Perhaps I'll slowly change it over time.
 

NH_burner

New Member
Dec 4, 2019
58
NH
Supply air trunk is 8x20, all the branches are 6" flex. Return air is a 14" round.

I opened the 3 vents to the 2nd floor sand static pressure dropped to just over 0.6" WC. Still lots of air coming out the front.

Next thing I think I'll try is to put a louverred vent on the supply air trunk to relieve the pressure. The lost heat is going to the basement either way but at least this way I'll get more efficient burning.
 

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brenndatomu

Minister of Fire
Aug 21, 2013
4,816
NE Ohio
What kind of filter(s) do you have in? If you go to a higher MERV filter that will lower the CFM output some too...
 
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brenndatomu

Minister of Fire
Aug 21, 2013
4,816
NE Ohio
Supply air trunk is 8x20, all the branches are 6" flex. Return air is a 14" round.
So supply duct is 160 sq inches (probably a bit on the small side) and then that goes into flex line?
Return line is 154 sq inches...which should actually be at least 10% bigger than the supply.
Just FYI, in case you plan to upgrade things at some point...
 
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