Potential Summer Project - Steam Beast - Replace Front Mount Pressure Gauge

LS123

Good morning all!
I have a really old steam boiler... it is supper solid (as it appears to be) and been in service at my place nearly 70 years. It is right size and really efficient, has a 0.85 GPH nozzle.
I would like to (that is if I can ) in the summer look in to having it changed by a pro or myself. I do not want to take a chance during winter season to replace the front mounted old pressure gauge (it may be rusted in the back where its connected to the boiler. Is it as simple as unscrew it and screw a new 30 PSI pressure gauge? Picture below.
Thank you!

Jamie Hall

I think my question would be... why bother? You seem to have another low pressure gauge up there in the shadows...

LS123

Good morning @Jamie Hall , reason being, my new 3 psi gauge on the pig tail (certified for Steam Boilers) shows 1/2 pound of pressure. Old front mount one shows about 1.5 PSI when the radiators are hot (when the burner has been running for about 20 mins.) It is confusing... I am assuming that the new PSI is accurate and both should show same pressure.. please see attached picture below. thank you!

LS123

@Jamie Hall as you had mentioned in the past it only takes few ounces of pressure for the steam to start going to the radiators... @Fred had mentioned based on another discussion that my boiler is right size for heating needs of the house. ... perhaps I could just look at the new psi ... I would love to keep this boiler as long as I can... It is solid, and efficient, use very little oil, has a nozzle of .85 GPH with Carlin 100CRD ( 0.5 to 4.5 GPH) thank you!

Jamie Hall

I think that if you look around various threads, you will find that the general experience is that that 0 to 30 pound gauge is pretty close to useless for the pressures we normally run at. It is there because there is a code requirement that there be a pressure gauge which will read up to twice the pressure relief valve setting, which is usually 15 psi. It's not intended to read what is actually going in, in terms of pressure, in the system -- that's what you have the low pressure gauge for.

It's not at all unusual for a relatively inexpensive gauge to be off as much as 10% of it's maximum scale reading after a time in service. Further, the gauge zero will drift over time -- I very much expect that yours has. I'd just regard it as a piece of decoration and history, and not worry about it.

LS123

@Jamie Hall ... thank you sir! ... I will leave it as it is... as little piece of history of old steam boilers... and I can depend on the low pressure gauge on the pig tail... I am so crazy about this boiler .... in fact I indent to have rebuild it slowly as long as heating chamber is solid.... it is part of history .... I have researched for boiler manufacturer and have not been able to find much yet... This boiler gives me something to keep busy and learn more about it and steam heating

SteamingatMohawk

How do you know the low pressure gauge is "certified for steam"? Can you give me the brand and model number?

pecmsg

Code requires a pressure gauge for the rating of the boiler in your case 30#'s.
With any pressure gauge you try too read the middle of the range. A 0 - 30# gauge is worthless for low pressure but required by code.
The 0-3# gauge is what you operate off of. I would suggest a shutoff valve below the low pressure gauge, open to read and close as a safety.

LS123

hello @SteamingatMohawk - I first bought one online, while it was 1/2 way to my house, I found out that one has max temp of 160 F and would not work with my steam beast ... , then @pecmsg and @Jamie Hall check onlne suggested google 0-3# pressure gauges... I found one... I call the people who sell it and they put me on the phone with product specialist and he confirmed one I bought from them was certified for all applications except corrosive liquid... it has been accurately working... I love the low pressure gauge.. and its on the pig tail... I found out that my boiler would not go anywhere near 1 PSI and boiler works well with about 1/4 of a one PSI... its fine with steam.. thanks again @pecmsg ...

Zoro.com, below link will take you to the product I have... and one below that link is my other discussion details in search of low pressure gauge

https://www.zoro.com/kodiak-low-pressure-gauge-bottom-3-psi-kc25-3/i/G6080090/?utm_source=ExactTarget&utm_medium=Email&utm_content=&utm_campaign=202002_ShippingConfirm_Transactional_None_All_None_1&smtrctid=149976349

it was delivered in less than 24 hours to my door steps...

My discussion from past ...

https://forum.heatinghelp.com/discussion/182648/new-pressure-gauge-for-steam-no-more-than-5-or-10-psi-max#latest

LS123

@SteamingatMohawk please note that as @Jamie Hall and @pecmsg you must have one 1-30 PSI gauge if it is steam boiler.... best!

SteamingatMohawk

@LS123 I looked at your link to ZORO and at the KODIAK web site. Two points,
Nothing specifically states it's OK for steam.
The temperature limit is 180F and the boiler runs at 212F+

Where did you find something that says it's good for steam?

SteamingatMohawk

I reread your post and I guess you accept what the rep told you.
Did you discuss the use of the pigtail with him/her?

LS123

@SteamingatMohawk yes... emphasize many time to her that 1-3 psi gauge for a steam heat boiler and must meet over 230 F. One reason I called them because I did not want to get again wrong gauge.... if you notice product description is has no max temp... second reason I called them to ensure gauge is certified with steam boilers... they guaranteed me it is certified for steam heat...

pecmsg

SteamingatMohawk said:

@LS123 I looked at your link to ZORO and at the KODIAK web site. Two points,
Nothing specifically states it's OK for steam.
The temperature limit is 180F and the boiler runs at 212F+

Where did you find something that says it's good for steam?

With a pig tail its not exposed to steam!

LS123

@SteamingatMohawk no I did not mention to them it was use with pig tail.... all I needed to know that its certified to use with a steam boiler and can operate at over 230 F ....When the boiler at its max performance and producing steam, I can touch the top of the pig tail. I learned from @JUGHNE , pig tail catch the water and bottom part of the pig tail gets hot (dont touch while boiler is hot) .... top part of the pig tail would not get that hot (probably can get hot... I dont know).... regardless I am comfortable with what I bought, and I trust the product specialist... there is a product warranty and its under $30.. now I get to see more detailed PSI of my boiler when operating at max...

LS123

@SteamingatMohawk ... sorry ... after I saw you post... I looked at the Kodiak website... I dont even see the gauge I got... perhaps I am missing something after... I specifically looked at their product category "Low Pressure Gauge"
https://kodiakcontrols.com/pressure-instruments/pressure-gauges/low-pressure-gauges/

I am happy with the one I have... and what I was told ... Perhaps you can call Zoro or Kodiak to get it confirmed... Best

Fred

Many, if not most of these gauges are not rated for steam, Except those designed for use directly into the boiler (I believe they say "Built in Syphon"). They are mostly rated for 140 to 160 degrees. That is why it is important to put them on a pigtail. That pigtail keeps the steam away from the gauge. Even the Pressuretrols and Vaporstats are rated for around 160 degrees. Use the pigtail!

WMno57

Back to the OPs original question. How do these come off?

Assume I'm at a demolition sale and have purchased salvage rights.

Is there a trick to pop the bezel off? Then cut the nipple or unscrew the gauge?

TIA

EBEBRATT-Ed

@WMno57 & @LS123

To get a wrench on the back of that back mounted gauge you can try pushing in on the boiler jacket. The newer boiler jackets are like tinfoil but the old boilers not so much. You may have to take the jcket apart to get the gauge off.

As an alternate you can put a new 30# gauge on the boiler elsewhere

LS123

@Fred thank you... as far as I can remember all I said was Steam boiler ... perhaps I may have mentioned pig tail but I dont remember telling them that...
@WMno57 what or who is "OPs" ... I am not sure how much you would get for old beat up pressure gauge or pig tail ... those are screw it in and screw it out ... may need some tool ... not sure if I answer your question...

LS123

@EBEBRATT-Ed ... my boiler is supper old.. I am not sure where else I could put a 30 gauge unless I add another pipe to the pig tail ... mine is old... most likely have to take the metal covers on the top.. see below... thank you for the info above

WMno57

OP is an acronym for Original Poster, which in this discussion is you. Just curious, is your native language something other than English? You seem to be picking it up. Your English is better than my Polish.

Ja lubię piwo

LS123

@WMno57 thanks for the explaining ... I believe my question has been answered...best!

SteamingatMohawk

@LS123 The KC25 series design is available in many ranges. The KC25-3# you mentioned identifies the specific range of the one you bought. Here is the web page.

https://kodiakcontrols.com/wp-content/uploads/2016/10/KC25-series-low-pressure-gauge.pdf

Look at the first gauge.

I am well aware of the need for a pigtail to protect the instruments. That being said I do not know of any specific temperature requirement for instruments used in pigtailed residential steam systems. Maybe some day I will come across it.

At the low pressure ranges we are talking about for residential steam, it is unlikely manufacturers will specifically mention steam as an approved fluid. The generic statement you see in many of the manufacturers' literature, I believe refers to the fluid in contact with the gauge, so in the case we are talking about, as long as a pigtail is used, the fluid is air with some amount of water vapor and whatever else is present, if anything.

The reason I engage in discussions about low pressure gauge installations is that they have very low maximum pressure limits. I have seen 110% of full scale on the Dwyer web site and discussed it with a Dwyer rep. What that means is if you install their 0-3 psig gauge in the system and the system pressure goes above 3.3 Psig (110%), the gauge integrity can be compromised, leading to failure/rupture, depending on how high the pressure becomes.

The 30 psig gauge that is required to be installed, will not be compromised as long as the 15 psig relief valve provides protection.

As many others have stated on HH, it is not a great idea to permanently install the low pressure gauge without an isolation valve to protect it from steam excursions above the gauge's pressure limit. I know that's an inconvenience and subject to human error, but it is better than the risk of a failure (I'm risk averse because my system is in a rental property and I don't live there).

The best choice is to find a gauge that meets the system requirements. I saw a Magnehelic gauge in one of the discussions, but have no specific knowledge of their capabilities.