Us stove vacuum problem

[Grocho]

Hi all,

I have a us stove 6039, I think, and I'm having some trouble tripping the vacuum switch. It'll run ok if the damper isn't all the way out, but anything within choir a half inch of all the way out causes the switch to trip.

Also, last year a different brand of pellets ran great on the default settings , with the damper all the way out. This year, I have the feed turned all the away down, fan all the way up , and I still can't run higher than hr 5 without the damper all the way out as the burn pot will eventually fill.

I've vaccuumed out the burn chamber, opened the exhaust blower and vacuumed that out, and vacuumed out the interior and exterior chimney pieces.

Don't know if it's related, but I've also had a problem with hopper fires this year. I've recently changed the seal at the top of the hopper hoping that would help.

Lots here, but hoping somebody can piece it all together, or point out something that I am neglecting to clean.

 

[Lake Girl]

Did you open up both clean-out ports in the rear of the burn chamber - see page 14 of the manual. I usually brush exhaust pathways with dryer lint brush and taped a piece of old garden hose to my shop vac adapter so I can run that up the pathways too. Not sure what configuration they are on the US stoves though...

(broken link removed to http://www.usstove.com/resources/OwnersManuals/English%20Owners%20Manuals/6039%20Manual.pdf)

 

[Grocho]

I've done the same with the shop vac and taped hose in the back cleanouts

 

[Lake Girl]

Was hoping it was an easy error that would solve your problem.... Do you have an OAK? What's the exhaust pipe configuration and size?

 

[Grocho]

I'm all for fixing the easy errors. I do not have an OAK, and ran fine all last year without one. Exhaust is 4" all the way out, but admittedly not ideal as it has 2 90° bends. As noted, I did clean it out within the last few weeks. I could open it up and try to clean it again once it warms up a bit outside (windchills to -50 today..)

Do the back cleanouts need to be screwed down tightly? When i moved in, the screws were loose enough that I can lift the cleanout plates out without loosening them, but they still hold the plates in place. I haven't tried tightening those down.

Also, are the gaskets in the exhaust blower critical, and do they fail easily? I pulled the impeller from the housing and RTV'd that joint.. I'm considering now also cleaning away the original gasket and putting a bead between the two flanges of the housing to make sure that one is sealed up properly. That gasket didn't look perfect when i had it apart for cleaning.

I'm still leaning toward something isn't cleaned correctly, as the airflow/vacuum problem seems to be getting worse with time.

 

[Lake Girl]

Manual recommends an OAK. I would also tighten up clean out plates so they fit snugly.

Check your vacuum line and switch, hi switches to make sure they are not malfunctioning. Failure likely caused hopper fire....

Gasket on the exhaust blower ensures that your family is safe from carbon monoxide. Replace with US stove or aftermarket gasket. Buy multiples so you always have a back-up. Make sure you have at least one CO detector.

Use the search function of the forum - Lots of US stove threads.

 

[Grocho]

Thanks for all of your help. How do I check the vacuum switch as you described? I must be terrible at searching these forums..

 

[Lake Girl]

While it may be your vacuum switch, it sounds like an OAK may help your situation. Have you used the same brand of pellets as last year again to rule out pellets?

Just going on what I have read on the forum ... disconnect vac line, suck on tube and should hear a click. Might want to replace tubing to rule out damage to the line. I disconnected mine from the vac switch (leaving it connected to exhaust housing ) and vacuumed out just to make sure there is no ash clogged there.

Edit: From another thread - https://www.hearth.com/talk/threads/quadra-fire-castile-insert-burn-pot-overfill.121116/

Test your stove's vacuum switch: open the door an inch or so while the stove is running. The flame should become lazy and pellets should stop dropping. Close the door, and the flame should immediately become lively and pellets should begin dropping again. If pellets continue dropping while the door is open, you should replace the vacuum switch ASAP.

 

[Grocho]

I am not using the same pellets as last year, and I am definitely not happy with the pellets I got as they seem to not burn as hot and create a lot more ash, and have more fines in the bag
So, checklist:

1. Tighten the back cleanouts so they are snug
2. Check vacuum switch and hose
3. replace gasket between exhaust blower housings. I'll have to check temp on the "paper" automotive style gaskets, otherwise I'll have to use RTV and wait for the 24 hour cure time.
4. Clean out exhaust venting again
5. Investigate OAK - I'm not immediately sure how I would do it given that the stove is in the basement, but i'm sure it would be an improvement in efficiency anyway. Why would it run fine last year and then need an OAK this year?

 

[Lake Girl]

With the OAK, it would have a consistent supply of air for combustion. The damper would be for fine tuning your burn. You are also throwing pre-heated air out the exhaust - costing you more dollars. Inside air used for combustion has to come from somewhere so it will draw cold air from around windows, doors, etc. making the house feel drafty. If house is fairly air-tight, you could create a negative pressure situation.

If OAK is a long run, it will have to be upsized similar to exhaust venting.

Hopper fire - low limit switch failure so it kept dumping pellets and backed up tube? Here's an easy test for the low limit...
From another thread: https://www.hearth.com/talk/threads/austroflamm-integra-still-no-go.119150/#post-1594824
OK, I removed the low limit switch and it looks fine. I googled it and found it is a normally open switch that closes at 120 degrees. I put an ohm meter on it and it is open. Took hair dryer to it and it closed. I can't say at 120 degrees, but didn't take long. I then put my thumb on the SS tip and it cooled down, and the switch opened. So in my opinion, it probably is ok. Any thing else I should check?

 

[Grocho]

I thought I would reply as an update to document for somebody's future reference. Again, thank you for all of your help.

Fixing the gasket on the exhaust blower - suction side seemed to improve my situation, but only temporarily. I also checked the temp switches, and the Normally Open one was open, and the Normally closed one was closed, so I think I'm in good shape there.

Thinking about the OAK, I realized that I had plugged a 3" diameter hole in one of the exterior walls of my house and also caulked a number of leak points during the summer, and these things would be acting against me. I also realized that fixing the exhaust blower gasket probably really only helped because the chimney was disconnected and air was free to flow inside (and you could feel it pouring in). I also remembered that I have a Radon system installed (with a manometer) that was fighting the pellet stove. Manometer showed nearly no pressure differential.

So, last night as the pellet stove went into "vacuum leak mode" again, I decided I would open a basement window and see what happened. Sure enough, the drape on that window pulled in as if there as a large breeze, and the pellet stove went back in to normal operating mode.

I will be installing an OAK this weekend.

 

[Bioburner]

Your getting to efficient

 

[Grocho]

Well, the OAK is in, and it seems to have resolved my problem. We got to talking to the neighbor about it and he mentioned that the previous owner of my house kept the laundry room window cracked open all winter...

Now if I could only get the darn thing dialed in.. I got it to both overfill and burnout overnight last night.

Thanks again for your help Lake Girl

 

[Grocho]

A couple days later, I am still struggling to get this thing to run like it did last year and actually heat my house. I have to either run it at a very low feed rate and high air rate or the burn pot will eventually overflow

The OAK on the 6039 has a cap that you're supposed to take off, drill 4 holes and re-install. The OAK dumps above the manual damper, so this is to serve as a draft setting. I've tried with the 3 holes, tried with the cap off completely, and am now running with 4 holes per the instructions. This got me thinking - is mass air flow (volume of air) most important, or is air velocity also important?

The problem is that I just don't seem to be able to get enough air to run above HR 3. to run at HR 3 I need to have my auger speed decreased from default, and my blower (high and low set points) Maxed out. I ran at HR 7 for 6 hours or so last night, but again I had my feed rates as low as they can go and blower speeds as high as they can go, and damper pulled out as far as I could get it to go without tripping the vacuum switch. Even at HR 1, I need to increase my blower speed quite a bit to get a good flame.

That's another thing, I am still fighting the vacuum switch. On HR 1 this morning, I opened the glass and it didn't trip the switch, but yesterday after several hours on HR3, I changed none of the set points, and the instant I moved to HR 4 the vacuum switch trips.The story wasn't much different even with the cap off, when I shouldn't have had an intake restriction of any kind. To get the vacuum switch to not trip, I have to turn the blower speeds way down, which then results in the burnpot overfilling.

I think I'm going to pick up a bag or two of pellets from last year and see how they burn. I went with Dejno's this year based on some advice and cost vs Uncle Ethan's last year. Otherwise, I am thinking maybe I need to try cleaning the exhaust again.

Any other thoughts?

 

[Grocho]

I went through and cleaned the whole thing again, vacuumed out the exhaust venting, and now I've got about 18 hours on it running on HR 9 at it's highest fan speed to get a good flame. It must just be that these pellets are difficult to burn (moist?), and they create a lot of ash and soot (if not burned with lots of air)

 

[Lake Girl]

What pellets did you burn last year and what are you burning this year? That may be the answer...

 

[Grocho]

Uncle Ethan's last year. Dejno's this year. Compared to the Uncle Ethan's the Dejno's have lots more fines, are not nearly as uniform in size, and potentially are the cause of a lot of burn problems. They were $40/ton cheaper, but if I can't build some confidence with them for the remainder of the season, I doubt I'll get them again.

I'm on day 2 with the heater running full-out and still going strong... I'm afraid to turn it down for fear I will start having the same problems again... so, I'm opening all the doors I can to have it heat my basement as well.

 

[Lake Girl]

Sorry, didn't recognize them as pellet brands ... not available here. Dejno's website has a section for raw materials they are looking for and their feedstock doesn't look stellar. woodpelletreviews.com mentions they are a blend of hard/soft woods.

Uncle Ethan's appears to be rebranded Rocky Mountain Pellets out of Colorado. High pine content due to using trees killed by pine mountain beetle.
https://www.hearth.com/talk/threads/same-pellet-different-bags.102509/ Apparently Rocky Mountain was bought this year by confluence energy.

Check UPC codes... Need some help getting UPC codes of the pellet bags.

You can always buy a better brand and mix to get rid of the Dejnos

 

[kinsmanstoves]

Hi all,

I have a us stove 6039, I think, and I'm having some trouble tripping the vacuum switch. It'll run ok if the damper isn't all the way out, but anything within choir a half inch of all the way out causes the switch to trip.

Also, last year a different brand of pellets ran great on the default settings , with the damper all the way out. This year, I have the feed turned all the away down, fan all the way up , and I still can't run higher than hr 5 without the damper all the way out as the burn pot will eventually fill.

I've vaccuumed out the burn chamber, opened the exhaust blower and vacuumed that out, and vacuumed out the interior and exterior chimney pieces.

Don't know if it's related, but I've also had a problem with hopper fires this year. I've recently changed the seal at the top of the hopper hoping that would help.

Lots here, but hoping somebody can piece it all together, or point out something that I am neglecting to clean.

Clean the venting.

Eric

 

[Mr._Graybeard]

I just picked up 3 tons of Dejnos. They burn fine for me. I wonder if the OP's batch had some water damage.

Oops, old thread. I've got to get a new calendar!

 

[Lake Girl]

It may be the pellets but OP may want to consider hooking up an OAK. IIRC, the stove is recommended to have one...

 

[Mr._Graybeard]

It's an old thread I resurrected by mistake, Lake Girl. Sorry about that.