Dwyer Model 25 or Dwyer Magnehelic 2000-00?

MudFlapLip · Post by **MudFlapLip** » Wed. Oct. 01, 2014 1:59 pm

I've read the manometer install posts over and over gathering some great info. I'm currently in the process of installing a baro and hope to have it done soon. Next on the list is a manometer. Other than their method of displaying a reading, are these manometers one in the same? The Dwyer Model 25 and the Dwyer Magnehelic 2000-00. I've read that the Model 25 has the ability to be periodically zeroed or calibrated to check for inconsistencies. Does this need to be done on a regular basis and if so does anyone know if the 2000-00 can be periodically zeroed or calibrated as well? I know some guys here prefer the Magnehelic so I'm hoping they'll chime in. I can get a brand new in the box Magnehelic off of ebay for $44 and free shipping and that's the one I'd prefer to go with.

Thanks,

Dustin

MudFlapLip · Post by **MudFlapLip** » Wed. Oct. 01, 2014 2:31 pm

Ok I just answered my own question. I called Dwyer direct and found that both units are calibrated from the factory and both can be manually zeroed as/if needed. The display basically boils down to preference. At this point I believe I will be going with the Magnehelic.

Keepaeyeonit · Post by **Keepaeyeonit** » Wed. Oct. 01, 2014 5:24 pm

Thats the one I have and I love it much better then the model 25 I use to have. Thats a good price for the 2000-00 Dwyer and Granger wants close to a $100.00. Keepaeyeonit

voodoochylde · Post by **voodoochylde** » Mon. Oct. 13, 2014 11:21 pm

I will NEVER trade my super-easy-to-read magnehelic for any sort of manometer. Got mine on eBay, NOS, for $25.

McGiever · Post by **McGiever** » Tue. Oct. 14, 2014 9:49 pm

Magnehelic Guy here too.

windyhill4.2 · Post by **windyhill4.2** » Wed. Oct. 15, 2014 5:04 pm

Do the Magnehelic's install the same way as a manometer ? I couldn't find an install specifically for the Magnehelic . Is their only advantage the dial with a needle pointer instead of colored fluid reading like a mercury thermometer on the manometer ?

McGiever · Post by **McGiever** » Wed. Oct. 15, 2014 5:13 pm

windyhill4.2 wrote:Do the Magnehelic's install the same way as a manometer ? I couldn't find an install specifically for the Magnehelic . Is their only advantage the dial with a needle pointer instead of colored fluid reading like a mercury thermometer on the manometer ?

Same install.
Advantages are no adding and subtracting oil to get hair splitting accuracy, no recalibration due to evaporation over time. A puff-back doesn't shoot the red oil out. Made of metal and glass and no plastic.

voodoochylde · Post by **voodoochylde** » Wed. Oct. 15, 2014 5:14 pm

They're much easier to read. I can make mine out from across the room. Other than that, I don't think there's any real functional difference. Both have to be installed level. I never have to worry about oil level with my magnehelic though. I'm not sure if one responds to change any quicker than the other.

windyhill4.2 · Post by **windyhill4.2** » Wed. Oct. 15, 2014 5:24 pm

No oil in the magnehelic ? I looked both up online but did not get a good idea of the difference in operating or installing the mano vs magnehelic.

McGiever · Post by **McGiever** » Wed. Oct. 15, 2014 5:53 pm

yep, no oil.

windyhill4.2 · Post by **windyhill4.2** » Wed. Oct. 15, 2014 7:12 pm

No oil .. so how does it get it's reading ? Does it still mount on the wall with a tube running to a hole in the smoke stack?

lsayre · Post by **lsayre** » Wed. Oct. 15, 2014 7:25 pm

Do a Google search for the term: "Magnehelic Principle" (including the quotation marks).

McGiever · Post by **McGiever** » Wed. Oct. 15, 2014 7:40 pm

What is a Magnehelic Gauge?

The simplest magnahelic gauge definition is that it’s an instrument used to measure pressure. It is mainly used in measuring positive or negative pressure (also known as vacuum); it also used to get the difference in pressures between two separate locations.

The magnahelic differential pressure gauge, or just magnahelic gauge for short, is the pressure gauge developed by Dwyer that can accurately measure pressure and pressure differences. In fact, the magnahelic gauge has set the industry standard in pressure gauges, and through the years Dwyer has been consistently raising the bar a little higher. Dwyer, ever since the company got started in 1931, has always been the industry front runner when it comes to controls and instrumentation technology.

Dwyer Magnehelic Gauge Specifications

Housing – The outer casing of the magnehelic differential pressure gauge is made of tough, die-cast aluminum, and powder-coated gray. It can withstand up to 168 hours straight exposure to salt water spray without any noticeable corrosion.

Accuracy – The magnehelic gauge can measure pressure difference at an outstanding accuracy of just plus or minus 2% at full scale.

Operating temperature – Magnehelic pressure gauges can operate efficiently between 20 degrees to 140 degrees Fahrenheit without losing accuracy, although this is just for the standard models. There are lower temperature models available upon request.

What Makes the Magnehelic Gauge Different from other Pressure Gauges

The thing that makes these gauges the best is that they incorporate the magnehelic principle developed by Dwyer. This principle gets rid of the problems that plague most of the other pressure gauges, problems like excessive wear, backlash, and toxicity. This results in a high-quality, durable, and accurate gauge.

Less Wear and Tear – The magnehelic principle is the patented method of transmitting the effects that air pressure has on a thin diaphragm to the indicator needle using only a magnetic linkage. This is the main difference that magnehelic differential pressure gauges have over the other gauges that use mechanical means to transmit the readings. This lack of physical contact between the parts mean that there is no wear inside the system that can affect the instrument’s accuracy in any way.

Fluid-less Design – There are numerous advantages to using Magnehelic gauge. Because there is no fluid present inside the instrument, the problems regarding accuracy loss due to evaporation or freezing is thereby eliminated. It also poses no risk of toxic contamination if the gauge gets damaged. The Magnehelic principle used in making these gauges also ensure a drift-free pointer movement that is not affected whatsoever by inertia.

High Durability – A magnehelic pressure gauge is extremely tough as well, considering the fact that it is a highly-sensitive measuring instrument. It can resist a respectable amount of shock and vibration, it is also relatively unharmed even when subjected to pressure surges of up to 15 psi, it is also unaffected by temperature fluctuations of up to 20 to 140 degrees Fahrenheit.

Easy Calibration and Installation – It is also a lot easier to calibrate a Dwyer Magnehelic gauge. The hoses just need to get disconnected and using the accessible adjusting screw on the cover, make the necessary adjustments until the needle points at zero. Installation is also a breeze, since the gauge is unaffected by gravity there is no need to install it at a level position.

Affordability – Despite being the best differential pressure gauge available in the market, the Dwyer Magnehelic gauge is very affordable. Though it employs cutting-edge technology to give users the most accurate pressure reading, it is still one of the most cost-effective instruments sold right now. Starting at just $55, these gauges certainly give a lot more value for money.

windyhill4.2 · Post by **windyhill4.2** » Wed. Oct. 15, 2014 9:41 pm

Near as I can tell, no fluid in the tube/s,just air ? I wasn't planning on a gauge for the EFM520 but goofed with my baro purchase,was planning on getting the one with the scale on it but.... So,i need to get 2 of them,1 for the boiler & 1 for the Crane 404 ,where is the best place to purchase ? Or ,do I just buy the proper baro with the built in scale ?

lsayre · Post by **lsayre** » Wed. Oct. 15, 2014 9:48 pm

windyhill4.2 wrote:Near as I can tell, no fluid in the tube/s,just air ? I wasn't planning on a gauge for the EFM520 but goofed with my baro purchase,was planning on getting the one with the scale on it but.... So,i need to get 2 of them,1 for the boiler & 1 for the Crane 404 ,where is the best place to purchase ? Or ,do I just buy the proper baro with the built in scale ?

A magnehelic has no tube, It is a gauge device with a scale and a pointer.