Quick advice sought for decent 3lb gauge for steam...

NJ08534

Greetings steamers!

Can someone please recommend a preferred 3lb pressure gauge model to supplement my code required 30lb gauge? The one I added is not reliable. Also, is there a pinhole protector etc that I should be adding to protect the gauge from water etc that might run up the attachment piping? I currently have it tied in off a mini t-valve and only open it to make a reading. Not sure this is best for the long run or not.




Thanks and sorry fir such a mundane question...!

Jamie Hall

Here's the one I have used on Cedric for the last 3 or 4 years...

https://www.amazon.com/Kodiak-Controls-KC25-3-Pressure-Gauge/dp/B00H9ZWLZG/ref=sr_1_3?crid=3D4ADSNTIKT96&dchild=1&keywords=0-3+psi+pressure+gauge&qid=1613570782&sprefix=0-3+ps,aps,361&sr=8-3

But there are many others.

If it's on a pigtail, it shouldn't need protection. If it's not, it should be...

STEAM DOCTOR

Nothing to do with quality of gauge but a three pack cost about as much as four individual gauges. All those years doing math homework with my kids. Finally paying off!!

Intplm.

No "pinhole" connection that I know of. However, you may need to add a pigtail to the bottom of that gauge. Every time you open that valve, raw steam is hitting that gauge causing it to fail prematurely.
A pigtail filled with water, and not the inevitable condensate, and then installed under the gauge, should help to add to the gauge lifetime.

mattmia2

It looks like it is on a water seal formed with a u in that iron piping, a different way of providing the same function as the pigtail.

Intplm.

Yes, @mattmia2 it does look like that but I was thinking that he needs a constant cushion of water.
And your response brings something to mind.
Do you think that gauge should be installed further below the waterline? Helping preserve that gauge.

Jamie Hall

Below the water line? Ah... no. You want to measure the steam pressure, not the water pressure.

EBEBRATT-Ed

A brass pigtail is what it should have. They make snubbers to install under gauges to stop pulsating pressure from damaging the gauge. I know they are used on water , not sure they can be used on steam

NJ08534

Here is a patent for a 1940s solution to protecting a steam gauge. Maybe I can find one :-)
https://www.freepatentsonline.com/2277534.html

yes indeed, that is a water U pigtail replacement made from iron pipe of the variety used by EzzyT and colleagues.  It provides a water fusion to protect the gauges and stats. It’s better than a pigtail as it can be cleaned very easily by removing the plug nuts at the end of each pipe and running a bottle brush through each. Reattach the nuts, add water and replace the final nut on top.  Much easier to maintain than the classic red brass pigtail.  I think making it with brass fittings would  be better than this iron version.  Ideally, making it from Pyrex or sapphire would be more fun as you could view it from the inside (but would of course be prone to breakage). 

Thanks for the advice on the gauge model. If it was good enough for your boiler you named “Cedric “ it should well for my boiler which is now named “Natasha” following your lead to naming to these beasts dwelling in our basements...!


-1791 Farmstead, expanded 1922
-Two Crown steam boilers, nat gas
-Central NJ

NJ08534

NJ08534

Here is a water snobbery to protects gauges....

https://www.supplyhouse.com/Winters-Instruments-SSN515-1-4-Brass-SSN-Water-Snubber-10000-PSI

ethicalpaul

I bought that one, it's no good. It is too resistant to air flow at our pressures. Your gauge won't see anything. If you notice, it's rated to 10,000 psi

EzzyT

@ethicalpaul I completely disagree, we install those exact ones all the time on our steam boilers and they work perfectly.

mattmia2

if you read the data sheet, there are like 30 different versions of it, maybe @ethicalpaul got the wrong one.

ethicalpaul

I bought the one from supplyhouse. I’ll give it another shot but I sure couldn’t blow through it AT ALL

SteamingatMohawk

We have had multiple discussions on HH about installing lower pressure range gauges in addition to the code required 30 psig ones. I have been preoccupied with another project, but a few weeks ago I checked both Dwyer and Kodiak manufacturers and both stated their low pressure gauges are only good for no more than about 30% overrange prior to losing their integrity (i.e., leaking or worse). Even a 5 psig gauge has the same design limitation. 5 psig x 130% = 6.5psig.

The point of this discussion is that none have the structural integrity at the boiler relief valve setpoint of 15psig. What that means is low pressure gauges should not be left in contact with steam pressure unattended. Using an isolation valve like in the photo is a good way to protect not only the gauge, but anyone near it in the event of a pressure excursion.

I did some additional looking around. There are some 3-way valves that can be installed to have the low pressure gauge on line with the steam in one position and vented to the atmosphere is another position.

Here are two different designs, "T" port and "L" port. Interesting

https://valveman.com/blog/understanding-tport-vs-lport-directional-flows/

Sorry it took so long to post this info.

SteamingatMohawk

Here is a pic

SteamingatMohawk

Series 2200 Magnehelic gauges are good for 35 psi and come in several ranges, but not cheap.

https://www.dwyer-inst.com/Product/Pressure/DifferentialPressure/Gages/Series2000#ordering

ethicalpaul

That’s strange because every Magnehelic says it’s rated to 15 PSI on it

SteamingatMohawk

I thought so, too, but that's not what's in the web page. After looking at it again, could it be specific to the note the 35 psi is in? That would be confusing, if in general they are rated at 15 psig, but for hydrogen pressure must be less than 35.

Strange it is, I have a recollection I saw a pic of a Magnehelic on HH and the face mentioned 15psig. However, I could not go back and find the pic.

In any event, the Magnehelic avoids any issue with pressure.

The L port valve is pretty straightforward, but the T port can be misunderstood, since that design seems to be less common. I've never come across a T port valve in my career or outside work.

mattmia2

You need the footnotes that the spec on the web site references but doesn't include so you would need to look at the actual catalog to sort it out.

ethicalpaul

Yeah sorry, I wasn't disputing that some models are rated for 35psi...I was expressing interest in the earlier statement that other pressures under 15psi would damage them...since every 2000 series one I have says right on the dial it's rated for 15psi.

kenlmad

ethicalpaul said:

I bought the one from supplyhouse. I’ll give it another shot but I sure couldn’t blow through it AT ALL

Try to inflate a balloon with your snubber. You will see it does indeed allow flow through it, but in a very "snubberly" way.

ethicalpaul

Well I had a pressure gauge on it that didn't lift off the pin, but I'll try it again

SteamingatMohawk

@ethicalpaul We have no disagreement. I think I may have misunderstood what the 35 psi comment on the web page is about. See the link below

My comment about pressures under 15 psig doing damage is not with regard to the Magnehlics. That's why I added the followup statement about them. My primary point is I checked two manufacturers and both had essentially the same statement about integrity for the standard type gauges (0-3, 0-5 and others).

I like the concept of the "T" port valve, because you can have both gauges on line at the same time, but without some clear markings, a person not familiar with the design might have some difficulty figuring out what is going on for the different valve positions.

As you probably already know, as a landlord, I am somewhat risk averse and want anyone who uses one of those gauges to have, as Joe Friday used to say on Dragnet, "just the facts Ma'am and all the facts".

@mattmia2 Here's the spec page for the 2000 series.

https://www.dwyer-inst.com/Product/Pressure/DifferentialPressure/Gages/Series2000#specs