St.Croix revolution vacuum issue

[DexterDay]

I'm getting frustrated, so stuck a piece of tape lightly across the outside termination. Ran all night without issue, but it's very warm here now and i usually only have trouble in the single digits. If it's cold (low 20s or below) running the thing on heat level 3 is not an option for me, I might as well hold up a glow stick. I need every BTU it's got to offer. If you hear back from Even-Temp on this issue please pass on anything they have to offer. But my guess is you won't - if your dealer calls they'll talk to him, but they don't want interaction with end users.

Running it that hard, does the distribution blower ever get a break? Or does it run constantly?

Mine on Level 1 will be on for 10-15 min, off for 10-15 (depending on auger trim level). On level 2 its on for about 25 min and off for 5 minutes. Anything above level 2 and the blower never gets the unit below my 115* set-point. I run it on level 3 in T-stat mode. So when its calling for heat the blower is on. But when its idling, its on for 10-15 off for 10-15.

Have it set to turn on around 170*-175* and off around 110*-115*...

Have you ever measured your air temps out of the registers? Or out of the actual plenum? Just wondering if anyone else has done so? And what temps you were getting? And on what settings?
I measure 10" off the top of the furnace inside the 10" duct and at the registers.....

 

[Beetle]

Could the EVL of my system be the problem, this furnace calls for 4" pipe. My calcs are as follows:

1 clean out ........5
1 90....................5
1 45....................3
6' horizontal......6
4' vertical...........2

Total...................21

If you have 4" pipe you should be fine if it is 3" pipe you have a problem.

Keep in mind that this furnace calls for 4" pipe

 

[tjnamtiw]

I think that tube is just for a reference pressure for the vacuum switch. The pressure near the switch itself may not be at ambient, so would mislead the switch, so they feed the other port outside the stove body. Just a WAG, but makes sense to me.

This is actually pretty common industry practice when measuring vacuum with a sensing gauge in an area upset with other vacuum or pressure sources.. I think you are correct.

 

[DexterDay]

Could the EVL of my system be the problem, this furnace calls for 4" pipe. My calcs are as follows:

1 clean out ........5
1 90....................5
1 45....................3
6' horizontal......6
4' vertical...........2

Total...................21

If you have 4" pipe you should be fine if it is 3" pipe you have a problem.

Keep in mind that this furnace calls for 4" pipe

Does that mean you have 3" on it??

And is it built as you described? In that order??

 

[Beetle]

no...4" on it.

 

[SmokeyTheBear]

If what tj is alluding to here: https://www.hearth.com/econtent/index.php/forums/viewreply/1089951/ is in fact the case you have other things in the furnace's environment that are fouling up the combustion air source as far as the furnace's sensors are concerned. Do you have outside air?

 

[Beetle]

yes...outside air

 

[Beetle]

here is my setup..

 

[SmokeyTheBear]

here is my setup..

Then ambient air for your install is not what that sensor is sucking on.

 

[Beetle]

It is sucking on the ambient conditions of the basement air...not outside air, if that is what your asking..

 

[SmokeyTheBear]

It is sucking on the ambient conditions of the basement air...not outside air, if that is what your asking..

Yes and with the OAK its ambient air to suck is the air outside not what is in your basement.

 

[Beetle]

this is the vacuum switch hose sticking out the side of the unit.

 

[SmokeyTheBear]

this is the vacuum switch hose sticking out the side of the unit.

Yes I know but with an OAK that ain't where your air is coming from, in other words plug the hole or get a longer tube and run it out side.

Did you folks get anything back from the folks that make the furnace?

 

[heat seeker]

I agree with Smokey - if the pressure in the basement is reduced by something, even the wind blowing, it will mislead the vacuum switch into thinking there's not enough vacuum in the stove.

 

[Beetle]

nothing from Even- temp. Based on what I have read I am not expecting them to respond...

I will extend the tube outside, worth a shot. a little reluctant to just plug it.

 

[SmokeyTheBear]

nothing from Even- temp. Based on what I have read I am not expecting them to respond...

I will extend the tube outside, worth a shot. a little reluctant to just plug it.

Have your dealer talk to them, yeah, I know what I'm asking, just covering the bases.

 

[slangtruth]

I think speculation as to where the reference to the vacuum switch is meant to be terminated should be left to the designers. Most stoves just have a switch, yes or no, and apparently since hoss's early number doesn't have it they started out that way here, too. They specifically changed it to have a floating reference, which they chose to just plop out into the ambient air outside the cabinet. It's not mentioned in the manual, and since as non-dealers none of us get to talk to Even-temp to ask for an explanation I'm hesitant to go dicking around with it. Beetle's empirical testing (he temporarily blocked it and the vacuum switch settled down) is evidence of something, but still needs proper explanation.

I said upthread that in my case I suspected I had too much vertical pipe outside the heated area. I had mentioned it to the HVAC guy who initially fixed my dealer's bad install. He pulled up earlier today and lopped a few extra feet off my outside vertical run, while keeping to local code (locally it has to terminate x inches above average annual snowfall, and also above the OAK inlet, which for me is the same thimble as the exhaust vent). We'll see if that has an effect when it's near zero out. It's not even running right now, it's 50 degrees outside. He and I both looked through the book backwards and forwards to find any sort of specification for maximum venting length, and it's just not there. My venting looks like this

double-tee cleanout at stove
about 3' vertical
45 degree angle
about 1'
45 degree angle
5 or 6' horizontal with rise, goes through the wall
double-tee cleanout
now 2' (was 5 or 6') vertical
90 degree to cap

With no published spec as to how much venting is allowed it's tough to know whether or not this is too much. A furnace is not like a living room stove and placement options are always going to be more limited, especially in an old building like mine where the first source of central heating was coal. The coal (now oil) furnace is dead center under the building to keep the duct runs as short as possible. No better path for my venting is apparent.

 

[slangtruth]

I'm getting frustrated, so stuck a piece of tape lightly across the outside termination. Ran all night without issue, but it's very warm here now and i usually only have trouble in the single digits. If it's cold (low 20s or below) running the thing on heat level 3 is not an option for me, I might as well hold up a glow stick. I need every BTU it's got to offer. If you hear back from Even-Temp on this issue please pass on anything they have to offer. But my guess is you won't - if your dealer calls they'll talk to him, but they don't want interaction with end users.

Running it that hard, does the distribution blower ever get a break? Or does it run constantly?

Mine on Level 1 will be on for 10-15 min, off for 10-15 (depending on auger trim level). On level 2 its on for about 25 min and off for 5 minutes. Anything above level 2 and the blower never gets the unit below my 115* set-point. I run it on level 3 in T-stat mode. So when its calling for heat the blower is on. But when its idling, its on for 10-15 off for 10-15.

Have it set to turn on around 170*-175* and off around 110*-115*...

Have you ever measured your air temps out of the registers? Or out of the actual plenum? Just wondering if anyone else has done so? And what temps you were getting? And on what settings?
I measure 10" off the top of the furnace inside the 10" duct and at the registers.....

When it's running at 4 or 5 my dist. blower is pretty much on constantly. Running at idle when it's warmer out, it cycles on and off. Measuring at registers isn't all that helpful across installations, since duct loss and ambient temperature are so much a factor. I did play with it a bit when I was trying to find the sweet spot for the damper, and at my farthest register (which goes through about 6' of 8x12 trunk also feeding four other registers, then about 10-12' of 6' sheet metal ducting, all uninsulated) with heat setting on 1 I could expect 70-75 degrees an inch or so above the register on a day with moderate 35-40 outdoor temps.

 

[SmokeyTheBear]

I think speculation as to where the reference to the vacuum switch is meant to be terminated should be left to the designers. Most stoves just have a switch, yes or no, and apparently since hoss's early number doesn't have it they started out that way here, too. They specifically changed it to have a floating reference, which they chose to just plop out into the ambient air outside the cabinet. It's not mentioned in the manual, and since as non-dealers none of us get to talk to Even-temp to ask for an explanation I'm hesitant to go dicking around with it. Beetle's empirical testing (he temporarily blocked it and the vacuum switch settled down) is evidence of something, but still needs proper explanation.


... snip ....

hoss has a vacuum switch on his furnace, his switch doesn't need a reference line which it appears the newer ones do, in which case the reference must be to the burn air source. In the case of a unit with an OAK that would be the outside air and never the inside air.

I also asked that both the manufacturer and the dealer be contacted.

No matter how one cuts it the use of an improper reference point is just that improper.

If a manufacturer doesn't want to answer a question from the owner then you go through the dealer, if the dealer doesn't want to answer or forward the question then I guess you are sol.

 

[hossthehermit]

At some point this weekend I'll have it down for cleaning anyway, and have some spare time. I'll try to remember to pop the side cover off and look at the vac switch, it may just sit there, or have a hose that terminates inside the surround.

 

[SmokeyTheBear]

At some point this weekend I'll have it down for cleaning anyway, and have some spare time. I'll try to remember to pop the side cover off and look at the vac switch, it may just sit there, or have a hose that terminates inside the surround.

Have you got an OAK on your furnace hoss?

 

[slangtruth]

hoss has a vacuum switch on his furnace, his switch doesn't need a reference line which it appears the newer ones do, in which case the reference must be to the burn air source. In the case of a unit with an OAK that would be the outside air and never the inside air.

Except using the inside air as a reference is exactly how Even-temp set it up. I can't be of any help - my dealer and I are not speaking. Hopefully Beetle's dealer will be willing to chase it down for us.

 

[hossthehermit]

No, I don't.
A. It would have too far to run, 14' horiz., 6' vert., 2 - 90's
B. It would have to run directly over my pellet stash
C. It would be in my way

 

[SmokeyTheBear]

No, I don't.
A. It would have too far to run, 14' horiz., 6' vert., 2 - 90's
B. It would have to run directly over my pellet stash
C. It would be in my way

Ok, just thought I'd get the ducks lined up.

Now I'm going to take your excellent advice hoss and go get a slice of Mrs. Bear's mincemeat pie and a cup of coffee.

 

[SmokeyTheBear]

hoss has a vacuum switch on his furnace, his switch doesn't need a reference line which it appears the newer ones do, in which case the reference must be to the burn air source. In the case of a unit with an OAK that would be the outside air and never the inside air.

Except using the inside air as a reference is exactly how Even-temp set it up. I can't be of any help - my dealer and I are not speaking. Hopefully Beetle's dealer will be willing to chase it down for us.

That sometimes happens between customers and dealers, certainly makes things more than a bit problematic.


I know that Even Temp set it up that way but things have been known to be incorrect from the factory. Then down the road after much gnashing of teeth things get straightened out until the next new thing comes along, lather, rinse, repeat.