My Maxx-MAdventure

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batchman

Burning Hunk
Oct 29, 2013
205
Backwoods MA
Apologies in advance for what will become a long thread I'm sure, since I'm a pretty vocal guy LOL.

After much research here and elsewhere I finally found the only stove that met all my intentions, the Maxx-M. Well, really the Maxx would also but I wanted the flexibility to try other fuels, especially since I've noticed the pellet market can fluctuate a bit.

My house came with a beautiful enameled wood stove in a nicely finished basement room, and a nice enough wood insert in the upstairs 'great room'. The basement wood stove will not draft properly, as I found during the 9-day ice storm/power outage 6 months after moving in. Took a few years to get the plan moving but replacing the wood stove with a pellet stove, given outside air and forced exhaust, seemed like the right answer. Next problem is that making that basement room hot doesn't do much for the area of the house we spend most of our time in, so the Maxx's duct kit and a little work seems like a fix.

Anyway with the stove chosen talking with a couple installers all insisted on stainless liner for my perfect condition chimney. My building inspector didn't think that was required, and given the cost of the liner I figured it was worth a try. So off I go installing it myself.

Wound up with 4" Excel Pellet vent going to my 6" masonry adapter, where I convert to flex and go 2 feet in and make a cut off 90 degree turn, kind of like a frenched exhaust tip. I am not happy with the 8 joints needed to get it out-and-up but that's how it's done. I was ready to go off-book and get some stainless bent- and welded-up, especially since my building inspector was not requiring double wall pipe (which is just replacing the single-wall stove pipe that was in place for the wood stove). But I understand the need for UL listing and gave it a go. I know, pics or it didn't happen!

Since I had concerns about the chimney venting and the local installer didn't use a Magnehelic gauge I picked one up on eBay for $40 or so, nabbed the Dorman oil pressure gauge kit from RockAuto (suggested here, thanks!) and plumbed it in - see 2nd pic. Draft is AOK on my test burns so far, with 0-degree cold stack or windy day not posing any problems - I am able to get the proscribed WC no problem.

DCP_0175.JPG DCP_0177.JPG

You might notice I've added aluminum screen to the back panels using a 3M high temp double-sided tape I got from DigiKey. This is because the Maxx, like almost every other pellet stove, has no provision for filtering room air and I have a dusty house plus a long-haired cat. At least with this stove I can do this - another reason I went this way. Another thing I did was to polish the sheetmetal hopper along the bottom to better help the pellets slide down - used some Zaino and it seems to help. I have since re-lengthed the exhaust and centered the stove in that tile floor detail LOL, but I do need to raise the stove 1/4" or so to get the length perfect. I got some hard rubber feet to go under the factory pieces.

My next two issues are a little trickier.

I intend to take outside air through the wall seen on the stove's right, but have some issues getting through that wall. More on that later. For now though the vexing thing is I did not want to use the usual 3" flex pipe as I think it would be tough to get the tight radius I want and also think it would wind up looking kind of crappy, besides conducting cold from the outside. So I found some pre-bent 3" exhaust pieces and a sleeve to go over the stove's inlet. Problem is, even though this is thin-wall (1/16th I think) pipe, coming straight back to the notch in the rear panel interferes with the cooling fan on the auger motor. I guess when using flex they would just deform it - I will have some trouble doing a good job of that on my 3" steel pipe. I thought about using 6" of the flex stuff to get past the auger but really want the fixed location to help support the weight of the intake. Wish me luck as I figure out how to support a 3" round pipe while crushing it in a controlled fashion.

Then there's managing shut-down during a power failure. A UPS will give me both the surge protection needed and will keep the exhaust blowing through a shut-down but man oh man it's going to take a big unit. I used a clamp meter and it takes a pretty consistent 3A for 1/2 hour. That's a stout UPS. I am debating using a more affordable one that should go 15 minutes, which seems to be 80% of the exhaust problem even from high, but that spec is for a new unit and I would bet it falls to 10 minutes after a couple of years. Then there's my next surprise, these stoves almost all lack a planned way to tell it to shut down. I thought about putting a relay across the overtemp but my dealer points out that takes a reset to clear, and I might be better off intervening in the vacuum circuit instead. As a test I tried a vacuum shutdown and it seems like that needs a user reset to re-start as well. Maybe I'll have to piggy-back on the thermostat circuit instead... Hmmm...

Thanks for listening, and catch you later!
- Jeff
 
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Man that is a big stove.Vented into chimney should not be a problem at all unless it is 40' tall.Only see 2 joints?Been using moly ofr graphite in hopper for a long time.Cannot see your screen,but if it is small like screen window you will greatly reduce air flow.Take that oak pipe to muffler shop and have that section ovaled,or pull the worthless little fan blade off.Looks good,stay warm!
 
You could use a power inverter and a optima battery it will give you the runtime you need. I am using a prosine inverter with built in transfer switch which transfers in 3 ms. Keep the T stat on normal power and if the power drops it will shut the stove down in 30 min(pilot auto mode) or so (on my eco-65 anyway) your stove similar I think. Keep the inverter and battery in another room/ far if you can far way from the stove, as a precaution from battery gases,(minimal anyway on that type of battery). What is the W.C number your seeing?
 
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Bob, I was pretty surprised once I had the pieces laid out. Stove to adapter to 5" pipe to T, then 6" slip-fit to 3' pipe to elbow, to flex adapter, to 2' of flex. I think I've figured out my plan of attack - I'll cut open a 3" PVC to make a round backer, then use a big pry bar as a die in a small arbor press. Wish me luck. I will say that this is a design issue and it kind of pisses me off - I mean I know the draft is important and I'm going a little long and with two 90s so I made sure I got mandrel bends for smooth flow, taking my automotive hop-up knowledge to heart. Maybe the cooling fan on the auger motor was an afterthought. Guess it'll be a good thing I mounted the draft gauge permanently.

As to the screening there's about 5 square feet of slotted area on the back covers, it sure looked to me like it'd be "enough" to prevent a restriction.

Hyfire, that might be the cheapest alternative but where the stove sits I've got two rooms to feed power from - the one the stove is in and the one my oil furnace is in. Maybe an AGM battery could run the inverter long enough - I have one in the race car I can try with - good idea, and will give it and it's trickle charger something to do over the winter!

So I haven't gotten to thermostat function yet but if I hear you right the wireless jobs will need 120v at the receiver and if that power drops the stove will shut down? Hey that'd be a whole lot easier than what I was figuring I'd need to do!

As to WC the stove manual calls a pretty narrow range of .15 to .17 for a hot stove on high and I can hit that easily and steadily but do need to tweak it if I change heat range on the stove. I noticed at startup it goes right to 2.

Thanks/Later,
- Jeff
 
To automatically shut-down my Ecoteck stove, if the power drops-out, I added a simple self-latching relay to the stove, with a set of NO contacts in series with the auger feed motor. When the power drops out, the relay interrupts the fuel feed and the stove shuts down as if it ran out of pellets. I have a UPS which continues to run the combustion blower through this shut-down period. The relay has a pushbutton switch so that the relay can be reset when the power is back. Of course the relay power is connected before the UPS.
 
Hi Pelleting, I was looking at doing the same thing but find the vac sensor easier to wire to. Missing link is telling the stove to re-start when power comes back - then to get really really ADHD about it I'd want to hold off the restart for 10 minutes of solid power... I think too much!

Cheers,
- Jeff
 
Use a relay in the stat wire. Once power is restored the relay will close and tell the stove it needs to start as long as the stat is calling for heat.

BTW, Nice stove. Thing is a beast!
 
Those W.C. numbers seem awefully low compared to what I am seeing, but my stove is not the same model. THe main thing that you should be concerned is that wen the pipe is hot that you have .05" w.c. of natural draft, with out the stove blowers running. The ups would avoid this scenario, if that fails a natural draft is good to have.
 
J - it makes sense to piggy back on the stat circuit, more I think about it. Just have to find the right wireless one and poke at how it works. And BTW your posts here are a wealth of info that helped me a lot in choosing this path - 3 cheers (assuming I get this all worked out!)!

hyfire - the figures came right out of the Enviro manual, but your point on natural draft is an excellent one that I had not thought of - something new to test!

Thanks much,
- Jeff
 
Natural draft will change depending on your stack height and temperature difference between the exh temp and the outside air. I was able to obtain .05" w/c with a a chimney height of less then 15 feet, so you should do that with ease. Im using a current innovations wifi Tstat, with an external 24v transformer, it works no issues. A optima battery should give you at least 1 hr run time, long enough to shut down upon a power outage, and if the power comes back you wont have to reset anything")
 
Well it's been a crazy couple of weeks. I was finally able to do a hot stove power-off test and got the same 0.05" draft as hyfire (thank goodness), and no apparent smoke leaks (thank goodness) but it's clear to me that if the stove were on high when it lost power I'd be risking overheating the heat exchanger. I think I must proceed with my original thought of a UPS for at least 15 minutes, 30 if I want it to re-start cleanly on regaining power.

Funny moment - after about 6 bags, plus some apart/together fussing, the stove stopped burning hard. It would light fine, get a good flame going, then die down after a few minutes - and setting the draft acted wacky. OK, so must be time to clean, right?

Except there's maybe 1/2 cup of ash in the drawer, burn pot just about spotless, in fact everything seems pretty darn clean. Hmmm, must be the exhaust - after all I don't really trust it anyway. Must be full of ash, since there's so little in the stove. So I had the up-pipe apart as I move the stove around and set the height, got maybe a tablespoon of surprise out of that - ah HA. Dropped the lid on the cleanout T, and after using a center-punch to put dimples in the outer pipe and the cap (to make it easier to line up), I got - drum roll, about a teaspoon of ash.

Seems in my fussing I must have knocked the switch from manual to hi/lo - and with no thermostat hooked up it seems that means just "LO". Mystery solved.

Along the way, now that I have the height set and my vent pipe aligned right, I discovered that not only does the cold air pipe hit the auger motor fan, the bottom cover won't bolt up with the vent pipe leaving the stove straight. Digging further, it seems they just did not update anything other than the nozzles for the intake and exhaust when they changed this stove model from 3" exhaust/2" intake to 4" exhaust/3" intake. I'm kind of pissed about that - this is not in keeping with the way the rest of the stove is put together. So now after three tries I've got the intake pipe dimpled enough to clear the fan but now it looks like I've got to slot the outer pipe on the vent, cut and/or bend the back panel, or probably both. Grrrr.

It now seems unlikely that I'll finish this install before I run out of winter, and my 3 tons of OK Platinum will probably go half un-burned, leaving them in the way of the shed I'm intending to build around them. Maybe with the shortage I should try to sell half a ton off.

I'll try later to upload a pic of the intake pipe and what I had to do it. I'd be tempted to wave it around in front of the factory, but I don't have an up-to-date passport - or enough time to cross the continent. But yes, I am that displeased.

Cheers,
- Jeff
 
Let them know anyway with pic, maybe they will have an explanation..... Glad you didn;t set the hopper on fire when the power went out, but it does make anyone Nervous when the heat exchanger starts to look like graphite core of Chernobyl...
 
What was your solution to the "AC power loss" and getting the stove to begin auto shutdown? Did you just series in a set of N.O. relay contacts into the T-stat circuit?

Also, did you ever identify the 3 amp 30 minute loading. I originally guessed the igniter, but 30 min is a long time. Maybe that's why they have such a short life.
 
==c
Well it's been a crazy couple of weeks. I was finally able to do a hot stove power-off test and got the same 0.05" draft as hyfire (thank goodness), and no apparent smoke leaks (thank goodness) but it's clear to me that if the stove were on high when it lost power I'd be risking overheating the heat exchanger. I think I must proceed with my original thought of a UPS for at least 15 minutes, 30 if I want it to re-start cleanly on regaining power.

Funny moment - after about 6 bags, plus some apart/together fussing, the stove stopped burning hard. It would light fine, get a good flame going, then die down after a few minutes - and setting the draft acted wacky. OK, so must be time to clean, right?

Except there's maybe 1/2 cup of ash in the drawer, burn pot just about spotless, in fact everything seems pretty darn clean. Hmmm, must be the exhaust - after all I don't really trust it anyway. Must be full of ash, since there's so little in the stove. So I had the up-pipe apart as I move the stove around and set the height, got maybe a tablespoon of surprise out of that - ah HA. Dropped the lid on the cleanout T, and after using a center-punch to put dimples in the outer pipe and the cap (to make it easier to line up), I got - drum roll, about a teaspoon of ash.

Seems in my fussing I must have knocked the switch from manual to hi/lo - and with no thermostat hooked up it seems that means just "LO". Mystery solved.

Along the way, now that I have the height set and my vent pipe aligned right, I discovered that not only does the cold air pipe hit the auger motor fan, the bottom cover won't bolt up with the vent pipe leaving the stove straight. Digging further, it seems they just did not update anything other than the nozzles for the intake and exhaust when they changed this stove model from 3" exhaust/2" intake to 4" exhaust/3" intake. I'm kind of pissed about that - this is not in keeping with the way the rest of the stove is put together. So now after three tries I've got the intake pipe dimpled enough to clear the fan but now it looks like I've got to slot the outer pipe on the vent, cut and/or bend the back panel, or probably both. Grrrr.

It now seems unlikely that I'll finish this install before I run out of winter, and my 3 tons of OK Platinum will probably go half un-burned, leaving them in the way of the shed I'm intending to build around them. Maybe with the shortage I should try to sell half a ton off.

I'll try later to upload a pic of the intake pipe and what I had to do it. I'd be tempted to wave it around in front of the factory, but I don't have an up-to-date passport - or enough time to cross the continent. But yes, I am that displeased.

Cheers,
- Jeff
I think you worry too much,you will not hurt the heat exchanger from power loss.As soon as draft motor stops you loose 2/3 of your air,pellets stop falling.Sit back,have a beer and stop worrying!==c
 
Glad you didn;t set the hopper on fire when the power went out, but it does make anyone Nervous when the heat exchanger starts to look like graphite core of Chernobyl...

I think you worry too much,you will not hurt the heat exchanger from power loss.


I did not think to feel the inside of the hopper - thanks for pointing out that risk, although I think I would have smelled warm pellets. I was all focused on smoking up the house, but to my surprise that heat exchanger must get some kind of hot when air flow stops - it felt like I was standing next to Chernobyl and it gave out a couple of clanks that made me limit my test to 3 minutes, at which point there were just a few embers. Bob, I try to worry "just enough" but often too much as you say. On the other hand I'll bet my stove is not built like they were in 1992!


What was your solution to the "AC power loss" and getting the stove to begin auto shutdown? Did you just series in a set of N.O. relay contacts into the T-stat circuit?

I haven't gotten to the trigger method yet but suspect it will just be to interrupt the thermostat, and if I hear other posters correctly using one that needs an external 24v wall wart might just take care of itself. If not then yes, I'll just series a N.O. relay assuming that thermostats work by closing the circuit. I think I need to get the heat distribution and thermostat worked out soon, running this stove at a steady "3" on manual ate a bag in around 8 hours.


Also, did you ever identify the 3 amp 30 minute loading. I originally guessed the igniter, but 30 min is a long time. Maybe that's why they have such a short life.

I put a clamp meter on one of AC wires, turned the hot stove off and saw it hover around 3A while the fans ran. They ran for pretty near 1/2 hour. No igniter; this is a pretty big stove.

Cheers,
- Jeff
 
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Actually you have a pretty well buit unit,just lots more bells and whistles.No stove mfg. would sell a unit that would be damaged from a power outage(well maybe the circuits if no protector)Heat input lowers instantly,plenty of steel to handle no air flow over exchanger(will have convection air flow anyway) .If was still burning(locked up convection blower)that is what the safety switch is for.Yes it is going to fell very hot,it is a huge stove.That stove will show a large increase on your electric bill.
 
I doubt its 3 amps, those clamp-ons are not accurate that low, unless you get one that works on a lower scale. Its probably slightly over 2 amps...good thing you got a small draft, you must have a pretty reasonable stack height? Buy one of those plug in watt meters...
 
I doubt its 3 amps, those clamp-ons are not accurate that low, unless you get one that works on a lower scale. Its probably slightly over 2 amps...good thing you got a small draft, you must have a pretty reasonable stack height? Buy one of those plug in watt meters...
Looked at the specs,3.6 amps!
 
Yessir I was pretty surprised to see a steady 3A but that distribution blower is a BIG motor. Plus the exhaust blower isn't small, and then there's another air pump for combustion, plus the stirrer it all adds up (not to mention the auger). I agree my cheapie meter is probably not really accurate (20A scale) but it does pass range of reason. The 3.6A would seem unusual as you won't have the distribution fan on at the same time as the ignitor but I guess it could happen if you power cycled a hot stove.

I actually worry my 35' stack height is too tall to defeat the cold downdraft but so far so good...

Cheers,
- Jeff
 
So for my next trick, I have been a little stuck on the outside air, which my building inspector is insisting on. The stove requires a 3" OAK and I think I've got a good setup brewing, but man that size pipe will feed a lot of air. In other threads I've been seeing figures like 80cfm, which I can believe on the exhaust side as that hot gas would be a much higher volume. Now that I have my 90 degree out of the stove in place, and no longer getting "zing"ed by the auger motor fan, I thought I'd see just how much draft that pipe has. Answer, next to none.

I am able to cover it with my hand and see no effect on the burn, although it was hard to contort and really see if there was a change in the draft gauge. I am going to repeat the experiment but clearly this stove has more air paths than this pipe.

One fellow I chatted with thought the air wash took air from under the stove but looking around I don't see anything obvious. There is an aquarium pump blowing seemingly right to the burn pot but that seems more like a "boost" than a main air supply.

For me the thing is getting a 3" pipe where I need it is not a trivial task. Seems a real shame to do that when it appears a soda straw would do. SO, do I hope that once I get this piping in place the stove might choose to use it, or do I need to totally disassemble this thing to box up wherever it's drawing from?

I'm looking forward to checking the draft gauge before/after totally plugging my cold air pipe. I'm not sure it'll hold piece of paper in place.

Cheers,
- Jeff
 
The pipe for the OAK in the stove is it a hybrid setup that shares inside air? You just need to look inside and see if its has an air gap?35 feet stack height is BIG, I can;t see it being a an issue as it only has an EVL of 17 feet.
 
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35 feet stack height is BIG, I can;t see it being a an issue as it only has an EVL of 17 feet.

Well I will confess I didn't climb up and drop down a tape measure, but it's tall. There's also 3 90's, 2 1-2' horizontals, and the ~6 feet of 30 degrees to vertical. So you can see why I was concerned.

I'll try to snap a pic of the OAK inlet, it's a very misleading piece. Nice nozzle with a flapper valve on a sheetmetal bulkhead - sure looked like it'd be sealed path to the air box. I don't think I can (or will) get that bulkhead apart any time soon. I just don't see where else it'd be getting air from, but I've lost track of my nose before!

Best,
- Jeff
 
Wow that's quite a stack, I think your height is the only thing helping you in case..I really need to see pics of the internals as this stove is a sister to mine...
 
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