Bought a Magnehelic gauge

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Snowy Rivers

Minister of Fire
Feb 7, 2010
1,810
NW Oregon
Been Running the Advantage II now for the last half of last season and up until current.

The stove has a pressure switch to shut off the feed if the vent plugs up, but does not have a switch to shut the stove off if the exhaust fan quits.

Not good as this could lead to some serious issues.

I decided that my upcoming rewire would also be enhanced by adding a vacuum switch to the fire box.

Sooooooooo I went onto Ebay and found a Magehelic gauge that is calibrated from 0 to .5" water column

With this gauge I can see what the fire box negative pressure is running and then order up a vacuum switch that will be correctly calibrated for the task at hand.

The little magnehelic cost me $40 including shipping.

Sooooo, I will be able to update the older Whitfield and make it a bit better/Safer.

Snowy
 
You're getting all hi-tech on us....I can't even spell magnehelic! !!!!
 
haaaaaaaaaaaaaaa

I just want to check the pressure/vacuum in the firebox so I can buy a vacuum switch that will work with the old Whitfield.

I am suspect that the switch thats used on a Quad or a few others will work.

The Old Advantage has zero protection against a failed exhaust fan.

This could lead to a firepot stuffed full of fuel and sit there and smolder and stink up the house.

Also if the door latch got bumped by the family pet and jarred open the stove would continue to feed pellets.

A door switch would be easy to install but would still not deal with the exhaust fan failure.

The ads on Ebay were numerous, I had to sort through many to find a gauge that read in the low numbers required. 0-.5 Inches of H2o

Once I have the actual firebox numbers Im will order a switch.

Snowy
 
does your switch have 2 ports for + or - pressure? if your current switch is before the blower it's neg if its after the blower it's positive. if it has both ports then run a new line to the other side of the blower. or get a harman vac switch and drill a hole into the intake and hook in there.
 
Thanks Ed



The Advantage II only came with a pressure side switch and it works fine for now.

My goal is, when I rewire the stove and add the complete new control system, to add the neg side switch too, to prevent the auger from feeding if the exhaust fan quits and or if the door should get opened by the family pet. (yes it has happened)


The new controls consist of a set of industrial quality timers from Precision timer company.
The one timer will control the on time of the auger (adjustable from .1 to 5 seconds) as well as the off time (Heat setting with adjustments from 2 seconds to 10 seconds)

This timer has the adjustment for the on time on the face of the timer and a remote pot for the ofoff time (heat setting) to panel mount.

The other timer is a one shot unit to bypass the low side temp switch during startup.

These are heavy duty undustrial items that are rated at 120V/10 amps

I will use a universal Triac control to handle the room air fan.

The final addition to the safeties is the vacuum switch in the auger circuit.

All the Original factory safety items will remain in the system.

This includes the two overtemp switches, One on the convection fan plenum and the other one in the air inlet pipe near the back of the stove.


Just some very much needed updates to what is already a great stove.

Come spring/summer, I will replace the fire brick backing too as it is erroded some near the drop tube area just above the fire pot.

Pretty basic stuff.

Also going to add an aluminum expanded metal cover to the rear of the stove. The original sheet metal cover over the rear of the mechanical cabinet was missing and I really dont want the grand kids to try parking their little toy trucks in there.

Having the back open with just us adults here is not even an issue, just dont want little fingers getting in there.

Actually having the back open probably keeps the fans and such far cooler as there is way more air ciculation.


Mostly just tinkering and uopgrading is all.


Snowy
 
i see you are going to put a vac sensor on the hopper. You may have to add a gasket and a bit of weight to the hopper lid to get it to seal tight enough. I'd guess you may have thought of it already, but I also thought it couldn't hurt to mention. Good luck.
 
Nope, not on the hopper.

Going to install a neg pressure switch to the firebox. The firebox on these run under a slight negative pressure.

The switch will not activate the auger if the exhaust fan quits or the door is open.

Most all the newer stoves have a negative pressure switch on the firebox.

This old stove has a positive pressure switch on the exhaust fan outlet to shut the thing off if the vent becomes plugged.

Having a switch connected to the hopper would not do much.

Snowy
 
You probably could have used a cheap automotive vacuum gauge also depending on the vacuum. I wonder why they sense vacuum at the exhaust instead of at the firebox to begin with. Why not just put a vacuum sensor before the exhaust input that will check for both blocked exhaust and open firebox?
Wiring it in series with the high limit switch?
 
oh, i see, i must have misunderstood. oddly, lennox is still using the pos pressure sensor on their newer units like the montage.
 
I see that.

Puzzles me that they have not installed a low pressure switch or a combination switch.

If the exhaust fan fails, it can be a real mess.

It will take a while for the low limit switch to cut off due to the drop in the exhaust temperature.

In the mean time the fuel keeps dropping into the pot and could really smoke up the house.

Plenty of universal switches that activate at a minimal negative pressure.

My aim here is to measure the fire box pressure with the stove running and see where it is under normal conditions, then buy a pressure switch that operates in the sweet spot of the switch.


I will likely drill and tap a hole in the fuel drop tube just above the firepot a few inches and install the barbed fitting for the vacuum switch.

Snowy
 
I don't know if it helps, but I can snap a few pics of the vacuum source location on a QuadraFire CB1200 (one vac sensor) and an Englander 25-pvdc (two vac sensors). Let me know.
 
Does the low limit switch on that model stop the auger? I wouldn't think so because how would it start? Usually the low limit is for turning the conv fan on.
Wouldn't it just smoke forever?
 
Is that gauge sensitive enough to measure the vacuum in the house (relative to outside) due to stove draft? I crack a window near my pellet stove, and I sometimes what the overall change in the inside/outside pressure differential is. If this pressure is lower, less cold air will seep into bedrooms that are far from the stove.
 
Snowy,

Whitfield has used, at different times, both + and- vacuum switches.

Positive = N/C Red Label

Negative = N/O Yellow Label

And perhaps you could find an after-market off the shelf model w/ both N/C and N/O contacts in your desired range???
 
MOS

I have been snooping.

The stove currently has the Red labled switch back on the LH side and its plumbed into the exhaust side of the blower.

Would be cool to find one switch that will do both.

I have found some small universal application low level vacuum switches.

Just waiting now to get my gauge so I can see exactly what the firebox depression is while its operating.

Likely in the area of .15 to .20 " H2O

We shall see. I am not really particular as I will just mount whatever switch I can get, into the cabinet somewhere close to the existing switch and just daisy chain the wires from one to the other and then on to the auger motor.

I am trying to find contemporary parts. I want stuff that I can replace easy should I need to.

The old Whitfields are great stoves but some of the parts are getting a little tough to get now.

Stuff like the feed motors, exhaust fans and room air fans are pretty basic and easy to mix and match.


I have found a really good sweet spot that this stove works just great, so I am going to se the new controllers so that the stove is either ON or OFF.

The room air fan has a spot that works perfectly so thats what I am going to set the new controls at. No need for extra knobs that the grand kids and fool with.

The heat range is perfect at 2 seconds of feed and 7 seconds off time.

The new conrtrols will be adjustable, but I am going to place the control inside the cabinet and not in the new panel.

I just start the fire and let the stove run, I never adjust the fan or the fuel feed at all.

Keeping it simple makes great sense to me.


Snowy
 
I am not sure what pressure the switch operates at, but the Englander 25-pvdc has two switches that have both neg and pos pressure ports.
 
I would think that most all these stoves will run a similar negative pressure in the firebox.

My reasoning is that the designs are similar as are the exhaust fans used.

The Englanders use of two switches of the same type is probably due to the fact that they can buy the same type "Dual mode" switch and not need to stock two different parts.

One switch keeps track of the exhaust stack pressure and the other monitors firebox depression.

Not really sure on that one.

All I know for sure, is that adding some extra safeties will not hurt anything, not even.

My Old WP50 Earthstove had very little. There was the overtemp shutdown snap switch that would have to be manually reset if the stove got too hot.

There was also a high temp switch that would turn the room air fan on high if the stove either got too warm or the operator had the fan shut off of at too low of a setting as compared to the fuel "Heat" setting.

That stove had the controls such that you had to turn the room air fan on and then you could vary the speed with the knob.


The controls have come a long way since that old Iron horse.

The Earthstoves were all Positive pressure fireboxes too and leaks and smoke had to be dealt with from time to time.

The beasts also had very little provisions for cleaning ash out of the upper baffles, as in none at all.

My stove got so clogged up that it would not run. I finally cut a round hole in the top plate of the stove so I could clean out the ash.

Made a bolt on cover that fastened on with 6 bolts.

That made the job of cleaning a snap from then on.


Snowy
 
Snowy,

My Omega has a 0.05" minimum switch. I hooked up my gauge and pushed in the damper until the switch cut out. Idling on low fire my stove is set to 0.08" Just fyi for you if you needed it.

Check grainger out for the switches here
 
Snowy Rivers said:
I see that.

Puzzles me that they have not installed a low pressure switch or a combination switch.

If the exhaust fan fails, it can be a real mess.

It will take a while for the low limit switch to cut off due to the drop in the exhaust temperature.

In the mean time the fuel keeps dropping into the pot and could really smoke up the house.

Plenty of universal switches that activate at a minimal negative pressure.

My aim here is to measure the fire box pressure with the stove running and see where it is under normal conditions, then buy a pressure switch that operates in the sweet spot of the switch.


I will likely drill and tap a hole in the fuel drop tube just above the firepot a few inches and install the barbed fitting for the vacuum switch.

Snowy

Great idea for an upgrade! I think the installation of the vacuum switch will ALSO shut you down if your exhaust plugged because you will lose your firebox vacuum, just like our stoves. No air flow = no vacuum.
 
Hey thanks for the tip on the Graingers switches.

I book marked the page.

$20 for that switch ios a deal and Graingers has a store less than 15 miles from me.

Surely a plugged stack would cause a loss of firebox vacuum too.

Will not hurt to have the systems redundant though.

Snowy
 
Snowy Rivers said:
Will not hurt to have the systems redundant though.

Snowy

Absolutely not. Thinking about it, as important as the exhaust is, redundancy is a great plus and safety improvement!
 
My thoughts exactly.

With this addition along with the new timers/controls, this stove should serve us for many many years.

Just taking a break after cleaning both the Whitfields. Cleaned them really well including the direct vent pipes too.

The Vent on the advantage was about 1/2 full of ashes, so it was a greart time to suck it out good.

My sucker hose on the shop vac will reach from the teminus almost all the way to the exhaust fan housing.

The little stove only has a 2 foot total vent pipe and stays cleaner longer.

The nut shells produce about 50% more fly ash than the pellets do so cleaning is a bit more important.

About once a week on the stoves and once every month or so on the vents.


Ahhhh yes, the duties of the stove "WENCH" ya know.


Snowy
 
Do you all have a link for the best Magnehelic gauge and whatever else I need with it? I need to get one to test a new PE Warmland that is smoking up the glass. The stove venting is a ICC PCOT Cleanout 90 right behind the stove adapter up about a foot to a 90 and then straight out 24 inches through the wall to a Jet Cap.

How would I hook the Magnehelic to the Pacific Energy Warmland?

Thanks Amigos,

AR
 
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