Furnace Filter - Manometer

[MasterSolenoid]

I have two Dwyer 'Analog' Differential Pressure Gages permanently installed to monitor my furnace filters.
They're the industrial kind and way overkill for home use. That's the way I like it.
The reason for using two is, I figured I would never send them out for calibration, and as long as they both read the same, I'd believe them.
Both measure inches of water. The range on one gage is 0-1.0 ........ the other is 0-2.0
Both gages work at the same time and do read the same.

Dwyer 2000-0 Magnehelic Differential Pressure Gauge (0-0.50"w.c.)

Dwyer 2000-0 Magnehelic Differential Pressure Gauge (0-0.50"w.c.). Great savings and get fast delivery when you order online at GlobalTestSupply.com. In stock, fast shipping!

www.globaltestsupply.com

Well. I just bought a 'Digital' Pressure Gage off Amazon.
Made in China and cost me $37.00
Problem: I compared it to my analog gage and it reads 1/3 less. / .35 VS .24
I did have it set to inch H2O

I just don't trust it and will return tomorrow.
I had high hopes for it and was disappointed. Oh well.

Furnace filters are always a good topic on here.
I change my furnace filter (heat only) by:
♦ Differential pressure
♦ Hold up to light and inspect
♦ Integrity - NO bulging
♦ Time in use not to exceed 6 Months

I'm just commenting on my purchase to see if anyone has anything to add.

 

[Skippy722]

I thought about getting one, but good ones are expensive and I can’t bring myself to trust the cheaper ones on eBay.

That being said…. Thermostat tells me to change it at the 3 month mark, that’s when I do it.

 

[tbm5690]

I go 9 months on my Aprilaire...5" filter and way more material so you can go longer. Some go a year but I undercut a bit for peace of mind.

 

[redbone3]

I have two Dwyer 'Analog' Differential Pressure Gages permanently installed to monitor my furnace filters.
They're the industrial kind and way overkill for home use. That's the way I like it.
The reason for using two is, I figured I would never send them out for calibration, and as long as they both read the same, I'd believe them.
Both measure inches of water. The range on one gage is 0-1.0 ........ the other is 0-2.0
Both gages work at the same time and do read the same.

Dwyer 2000-0 Magnehelic Differential Pressure Gauge (0-0.50"w.c.)

Dwyer 2000-0 Magnehelic Differential Pressure Gauge (0-0.50"w.c.). Great savings and get fast delivery when you order online at GlobalTestSupply.com. In stock, fast shipping!

www.globaltestsupply.com

Well. I just bought a 'Digital' Pressure Gage off Amazon.
Made in China and cost me $37.00
Problem: I compared it to my analog gage and it reads 1/3 less. / .35 VS .24
I did have it set to inch H2O

I just don't trust it and will return tomorrow.
I had high hopes for it and was disappointed. Oh well.

Furnace filters are always a good topic on here.
I change my furnace filter (heat only) by:
♦ Differential pressure
♦ Hold up to light and inspect
♦ Integrity - NO bulging
♦ Time in use not to exceed 6 Months

I'm just commenting on my purchase to see if anyone has anything to add.

"digital" does not mean better or more accurate. You must consider the actual specifications of the measuring device.

 

[Donald]

I have a wide filter in an Aprilaire media filter housing. It gets changed once a year.

 

[AZjeff]

A manometer is a great tool. We had Dwyer U Inclined manometers on paint and dust booths to monitor the filters. How did you determine what amount of restriction to go to with the filters?

 

[Fitter30]

0-2" is the one to use. new filter will read .03 dirty filter 1.0 . Most filters dirty is 1" from clean

 

[MasterSolenoid]

A manometer is a great tool. We had Dwyer U Inclined manometers on paint and dust booths to monitor the filters. How did you determine what amount of restriction to go to with the filters?

Step 1) Furnace Manufacturer spec sheet shows .50 max (inch of water)
New filter (1x16x20) reads .32 (MERV 10)
After 6 Months reads .38
I feel very comfortable NOT going over .40

I just went 8 Months and gage read .38
I changed it anyway.

 

[MasterSolenoid]

A manometer is a great tool. We had Dwyer U Inclined manometers on paint and dust booths to monitor the filters. How did you determine what amount of restriction to go to with the filters?

Here is a previous post about furnace Pressure Gages.

When to Change my 4 Inch Furnace Filter?

I just installed one of those 5 inch furnace filters. I attached one of those vacuum differential devices as well. When furnace blower runs in propane mode is shows .20 inches of water. When furnace runs in HP mode is shows .30 inches of water. Reason being the fan runs slower in the Propane...

bobistheoilguy.com

 

[Gillsy]

I have central air, and live inn upstate New York. Furnace/blower sees year round service. I just replace the Merv 11 every 6 months.

 

[MasterSolenoid]

Was looking for a Winter project.
I just updated my furnace pressure gage by adding an Inclined Manometer / good price on E-Bay.
Both gages read the same.
The Inclined Manometer is nice because there are no moving parts.

Magnehelic will only be used if I question the Inclined Manometer / and it looks cool.

I will change the Filter sooner rather than later, but most likely will get more use out of them as when I had NO gages.
1) Age - How long in use .... (Months)
2) Construction Integrity - Any bulging caused by air pressure (or course I want NONE).
3) Amount of Dirt & Color - Hold up to light and inspect
4) Differential Pressure Gage - Target <.40 .... (.50 max)

 

[MasterSolenoid]

Well, if you look at my photo above, gage shows a reading of .34"wc / using a 1" MERV 10 filter.
Other 'new' filter readings are:
Filtrete 1900 / MERV 13 .... gage shows .... .27"
Various other 1" brands / MERV 10 .... .32"
--------------------------------------------
BUT, I just had installed an Aprilaire 4 inch filter cabinet.
Gage reading is now .... .08"

That is quite a drop in differential pressure.
The fan & motor actually sound quieter.

 

[vwmaniaman]

My furnace or AC just have me to look at it and see it looks dirty. Then I change it. I tried the thick fancy ones and it made the furnace bonnet pop back and forth like a jar lid. Went back to the cheapies and now no popping. Just change more often.