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Posted

Hi,

 

I'm looking for some recommendations for a differential manometer to monitor stove flue vacuum.

 

The stove I've got has a cold vacuum of 0.02"WG and warm vacuum of 0.07"WG.  When I've looked at the offerings on Amazon etc, they don't have the required accuracy at these low values.

 

Any recommendations?

 

Thanks.

Posted
2 hours ago, SteamyTea said:

The BME280 works in the range you are after, can you cobble up something with one of them and a Raspberry Pi?

He is looking to measure pressure not air pressure. 

Posted
9 minutes ago, Adrian Walker said:

He is looking to measure pressure not air pressure. 

 

9 hours ago, DG77 said:

WG

That is Water Gauge, which is a pressure.

One inch of water is 490.08 Pa.

A pascal is a derived unit of pressure [kg.m-1.S-2] or stress [kg.m-1.S-2].  Same units however you look at it.

Then we have the Cold or Warm part, which allows for different properties at different temperatures, which makes the BME280 even more suitable.

 

  • Like 1
Posted
On 30/10/2025 at 16:54, SteamyTea said:

The BME280 works in the range you are after, can you cobble up something with one of them and a Raspberry Pi?

According to what I've read that is an absolute sensor, not differential.  Also, the stated accuracy is ±1hPa which equates to 0.4"WG.

There doesn't seem to be much that is accurate at those levels - but most stoves would have similar hot/cold flue vacuums.

 

Posted
1 hour ago, DG77 said:

absolute sensor, not differential

Yes, so would need two.

 

1 hour ago, DG77 said:

accuracy is ±1hPa which equates to 0.4"WG

Possibly, I can't remember.

 

I did buy a couple of small differential pressure sensors, but never got around to using them.  Not even sure where they are now.

  • Like 1
Posted

I'm only going to compare the vacuum between two back to back stoves which has one underperforming, so I probably don't need that level of accuracy - just need to compare the values between them.

 

So some sort of semi accurate device at that range.  There doesn't seem to be anything out there when you consider the accuracy and linearity values.

Posted
On 30/10/2025 at 10:27, DG77 said:

Any recommendations?

Yes. 

 

1/ Invest in a good Co monitor. 

 

2/ Check your flue.

 

3/ Accept that if you have not run the stove for a few months you will get a "funny smell"  as it dries out the surrounding structure.

 

4/ When was the last time you replaced the door seal to the stove? bet you have not! 

 

5/ The flue vacum will change as the chimney warms up.. you are chasing the dragon here. 

 

If you check the basics then come back to us describing the problem in more detail. 

6 hours ago, DG77 said:

I'm only going to compare the vacuum between two back to back stoves which has one underperforming, so I probably don't need that level of accuracy - just need to compare the values between them.

 

So some sort of semi accurate device at that range.  There doesn't seem to be anything out there when you consider the accuracy and linearity values.

Why are you indulging in this? Have you not got something better to do? The flue pressure will change a lot depending on which way the wind blows! I know this as I'm an SE.

 

The reason I'm being a bit rough with you is this. 

 

Young and new self builders may look at your posts and get worried that self building is so hard these days, it's not worth the effort. I think it is the best thing you can do, is to build your own house!

 

I'm here to encourage young folk as they are the future!

 

But they do need information from folk like myself to enable them to make informed decisions.

 

Make no mistake here, many of my posts are intended to inform.. it up to you as grown ups to decide!

 

 

 

 

 

Posted

1. New Build so the CO monitor is mandatory.

2. Flue was checked and cleaned by installer when they returned recently.

3. No smell from recent lights.

4. Door seal has not been replaced - stove has been rarely used.  However, when I switched the door to the working stove in adjacent room there was no issue.

5. Okay.

 

This stove has been problematic since install.  I've got it close to where it needs to be, but would like to get it fully done.

Not sure how I'm worrying other self builders TBH.

 

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