What vacuum reading should I be getting in an Englander 25-PDVC?

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kharrisma

New Member
Dec 21, 2018
37
Bristol, NH
Hi Folks,

I know, I've already asked this question, but I'm getting conflicting answers. I've emailed Englander tech support twice (once a few days ago, and again day before yesterday) and have yet to receive a reply... which in my experience is unusual for Englader tech support. I'm hoping one of their guys might read this and post an answer.

One answer I got was "0.05"wc" and another reply directed me to another thread in which one of the Englander guys says that the combustion chamber vac switch ("door open switch") would go open at 0.17" wc. Those numbers ain't adding up. If it opens at 0.17, then the claimed 0.05 can't be correct, since it's far less than 0.17. Obviously the reading should be higher than 0.17, but how much higher?

And while we're on the subject of vacuum, what do you guys think about this:

https://www.ebay.com/itm/Hti-HT-189...h=item5216c27448:g:XeQAAOSwEVlcJZC6:rk:1:pf:0

or this:

https://www.ebay.com/itm/LCD-Digita...rksid=p2047675.c100005.m1851&autorefresh=true

as an alternative to the more expensive Magnehelic gauge that I've encountered fairly often in this and other forums? Anybody used one, or one like them? Opinions?

And finally, I still never really got an answer about which Magnehelic gauge you HVAC and stove guys use. Again, I got a reply, but it was just a link to an ebay sale, and from the pictures and writeup, it wasn't apparent which model the gauge was. I'd just buy the thing, but it's not a lot cheaper than a new one, and given that fact, I'd rather just buy a new one and get the warranty that comes with it. There are a LOT of gauges on offer at their site of all different scales and ranges. The scale would be inches of water, but for the appropriate range for this application, I'd just be shooting in the dark without a model number.

Your patience and input is very much appreciated.

Oh, and if you've been reading my other posts about lazy flame and lowered heat output.... I decided to check the OAK intake again, figuring it might have a leaf across it or something (been really windy hereabouts lately.) It's really not easy to get a good look at the intake because of the deflector plate over the opening, so I removed the plate... and there's this big mat of... something... like hair/dryer lint/bug litter/and ??. I'm guessing that this just might possibly be a contributing factor in my stove's issues. Just maybe. :) Pulled the whole intake plate off, scrubbed it clean, and shined a flashlight into the flex-piping, just to be sure, and while it's dusty, it's clear. So I guess we'll see if there's any improvement when next I fire it up. Also: realized that the pellets I've been burning are at least two years old (there's been a gawdawful lot of things going on around here lately, and this fact just got overlooked,) and while they are out of the weather, the little blister shed they're in is dirt-floored (got pallets as a secondary "floor" to keep the pellets off the dirt,) i'ts still kind of a damp environment during the warmer months. Tried burning some fresh stuff, and the stove is running at least 90 degrees hotter than before. Starting to look like a bunch of small errors, rather than one big problem. Again, thanks for the input you all gave so generously.
 

Ssyko

Minister of Fire
Nov 6, 2017
4,204
Lorraine NY
Ok the difference in wc measurements is stoves built before 2006 had an older switch that activated at 0.05wc. In 2006 and later model pellet stoves use 1 ea CU-VS .05wc and 1 ea PU-VS .17wc now your older stoves just use the CU-VS x2

First link that tool is listed as a Pressure tester. Does it work on vacuum to?

Sec link. Same thing but in the specs thr margin of error is larger than what you want to measure to start with.
 
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kharrisma

New Member
Dec 21, 2018
37
Bristol, NH
You need to get one that measures + or - 2 wci

@Ssyko: This gets awfully nitpicky/technical real quick and in a hurry... I can't get what I would consider a straight answer on this, like a "Yes, it will read vacuum." Apparently, this is what the "differential" in the description means: in measuring 'vacuum,' you're not dealing with a true vacuum (read: outer space, no atmosphere whatever.) The 'vacuum' being measured in any on-earth application is in reality just a lower-than-atmospheric pressure... it's still pressure, just less than ambient atmospheric. The way a differential gauge works, in this application anyway, (greatly simplified) is to measure ambient atmospheric in one port, the 'vacuum' you're measuring in the other port, and the display shows the difference between the two, in whatever scale you choose to display. Only exception to that would be in high-vacuum situations used in manufacturing of some things, and in research labs and such, where they pump things down to as close to an absolute vacuum as can be achieved using current technology.

This can get almost philosophical pretty quickly; there's actually no such thing as a perfect vacuum, in reality. Even in the space between galactic families, there are still a few atoms floating around per cubic meter of space, which for any practical purpose would be a total vacuum, but a true vacuum would be no matter at all... not so much as a single atom. So, again, for all practical purposes, when we're talking about vacuum, it's actually differential (or relative) pressure. Like there's no such thing as "negative voltage." "Negative voltage" is just a lower voltage than a 'reference voltage.' I used to run into this in dealing with wire-guided forklifts. They used a 'reference voltage' of 7.5 VDC as their "zero," meaning truck centered dead-nuts over the guidewire. If the truck deviated in one direction, the input voltage would go down, lowering from the 7.5 volt reference, and if it deviated in the other direction, the input voltage would climb from the 7.5 reference. To make things less awkward to discuss, they used the terms "negative voltage" and "positive voltage," with respect to the base 7.5 volts. Same concept, different application. I really hope I'm not coming across as being too pedantic; this is where all the searches and queries have led me.

I've queried them about measuring 'vacuum;' if I get any kind of meaningful answer I'll post it back here.

And I agree with you about the +/- margin of error on that second link; looks awfully 'coarse' for what I'm trying to measure.

@JRemington: Thanks; that's exactly the answer I've been looking for. MUCH appreciated!
 

JRemington

Minister of Fire
Nov 4, 2017
709
Belleville New York
The plus and minus isn’t for the margin of error. It’s for reading negative or positive pressure in water column inches. If it helps I have a Dwyer. If I had it to do over I’d get a digital.
 

Connecticut Yankee

Burning Hunk
Nov 20, 2018
201
Connecticut
. . . Even in the space between galactic families, there are still a few atoms floating around per cubic meter of space, which for any practical purpose would be a total vacuum, but a true vacuum would be no matter at all... not so much as a single atom. . . .
And even then, quantum fluctuations prevent the existence of a "true" vacuum. Physics, gotta love it!
 

kharrisma

New Member
Dec 21, 2018
37
Bristol, NH
The plus and minus isn’t for the margin of error. It’s for reading negative or positive pressure in water column inches. If it helps I have a Dwyer. If I had it to do over I’d get a digital.
For the less than $30 that some of the digital ones cost, I'm going to pick one up. Worst that can happen is that it won't work in my application, and I can always send it back.
 

bob bare

Minister of Fire
Oct 31, 2013
3,136
park county montana
Some england's stoves use 2 different switches,and I believe they are plugged in to different ports on the stoves.You can go to East Coast Hearth,look up the switches,and there is real good descriptions.
 

kharrisma

New Member
Dec 21, 2018
37
Bristol, NH
Some england's stoves use 2 different switches,and I believe they are plugged in to different ports on the stoves.You can go to East Coast Hearth,look up the switches,and there is real good descriptions.
Hi Bob,

Yeah, the stoves made after 2004 have dual vacuum switches: one connected to the burn chamber, and the other connected to the combustion blower plenum. One goes open at 0.05 inches water column, and the other goes open at 0.17 inches water column. Thanks; I've been lurking up there, too.
Ok the difference in wc measurements is stoves built before 2006 had an older switch that activated at 0.05wc. In 2006 and later model pellet stoves use 1 ea CU-VS .05wc and 1 ea PU-VS .17wc now your older stoves just use the CU-VS x2

First link that tool is listed as a Pressure tester. Does it work on vacuum to?

Sec link. Same thing but in the specs thr margin of error is larger than what you want to measure to start with.
Hi Ssyko,

Queried Amazon (they have it there, too), and got this reply:

"This does measure vacuum. I use it for measuring vacuum in units of inches water column and it performs well. I verified it with a Dwyer Magnahelic gauge and it had comparable accuracy. I used it to measure the suction under my basement slab in order to optimize my radon system fan placement. I am mechanical engineer and I'm not easily impressed, but I was amazed with how well this performed (for my purposes). For checking a pellet stove draft, I'd want to make sure hot gasses don't enter this device. It's a dual port, so it can also measure differential pressures. There are also probes available which you could use to measure flow if that is of use to you. This became one of my favorite tools while on my radon project."

This is for that first link, the white meter. Sounds fairly definitive to me.
 

bob bare

Minister of Fire
Oct 31, 2013
3,136
park county montana
Hi Bob,

Yeah, the stoves made after 2004 have dual vacuum switches: one connected to the burn chamber, and the other connected to the combustion blower plenum. One goes open at 0.05 inches water column, and the other goes open at 0.17 inches water column. Thanks; I've been lurking up there, too.

Hi Ssyko,

Queried Amazon (they have it there, too), and got this reply:

"This does measure vacuum. I use it for measuring vacuum in units of inches water column and it performs well. I verified it with a Dwyer Magnahelic gauge and it had comparable accuracy. I used it to measure the suction under my basement slab in order to optimize my radon system fan placement. I am mechanical engineer and I'm not easily impressed, but I was amazed with how well this performed (for my purposes). For checking a pellet stove draft, I'd want to make sure hot gasses don't enter this device. It's a dual port, so it can also measure differential pressures. There are also probes available which you could use to measure flow if that is of use to you. This became one of my favorite tools while on my radon project."

This is for that first link, the white meter. Sounds fairly definitive to me.
Yes,I know this stuff,i was posting it for you.
 

bob bare

Minister of Fire
Oct 31, 2013
3,136
park county montana
Just experience.buy a cheap china digital gauge,buy 2.If you drop it,knock it,your kid plays with it,there is no way to tell if it became inaccurate.A mechanical sweep gauge,you can reset to 0,and can tell by the action of the needle if there is a problem.Do you check your cars tires with a 99 cent digital gauge?