Does any one know how to read this


This is a pressure gauge on a boiler, just wondering if someone can descripe the gauge readings.




Pressure on top.

Temperature on the bottom.

Great! Thank you Michael.


10 psi
170 f


Are you out doing inspections and not knowing something as basic as this?

Before I ask that , How many really deal with boilers it was a good question .No wonder everyone hates to ask anything on here. There is no stupid questions you know. Just dumb ***'s that think they know everthing

I bet those Canadians deal with boilers a lot more than redneck hillbilly transplants from Canada do. Give the guy a break, he is a certified inspector.:wink:

You may be surprised you grumpy old gangster lol . I lived n Northern Ontario hardly no residential boilers there. If there was they where almost as old as you. You know the type open expansion tanks in the closet .

He is a dues paying NACHI member is it really any of your business on this

I deal with boilers fairly often, and haven’t seen that style gauge (TPV) in quite a while. Typically, the temp and psi are seperate gauges around here.

Not a dumb question, IMO.

I was not referring to him asking the question i think it was a good one I was referring to a post that was sort degrading him for asking
See Post #6

In my part of the Atlantic provinces, about 15%+ of homes I inspect have boilers…in some subdivisions, they are much more common than that!

I asked the question as I was leading to a caveat about doing inspections without some longer term mentoring could lead to court. I was talking to NS’s first CMI this morning and he claimed one of his unassociated local competitors was in court for his second time today!!!

Are you guys too mild to tell him how rough this field can get when lawyers get involved?

And how the weasel clause may not save his *** in court, etc, etc etc!!

You asked a “loaded” question, and only you knew where you would be going with it! The rest of us had a good idea though.

Perhaps you should just say what is on your mind, instead of playing “bait the newbie”. What you posted above would have been more useful to the OP. Maybe.

Looks like 10 psi and 180****°F to me. Note that the top needle has pressure readings in both PSI (upper scale) and H2O Ft (lower scale).

The boiler is likely at or near the operating (cut-out) temperature, but that pressure reading is too low. Should be around 20 psi (give or take a few psi).

Either that gage is broken, or there is a problem with the system (air bound, leak, etc). Make sure the needle moves as the system heats up and cools off.

Robert read it again!
10 PSI would be okay at standing mode and should have no more than 15 PSI according to boilers age.
20 PSI is over the rating recommended on most pressure valves.:smiley:
30 PSI for TPRV.

Depends on the vertical distance to the highest piping served by the “boiler” with 12 psi typically being the minimum.

The Pressure relief valve is likely set at 30 psi.

Michael beat me to it…12 psi is typical, and what my manufacturers installation book states is the ideal pressure.

OOPS! 30 PSI for this application.:smiley:

For a typical standard efficiency residential hydronic boiler 12 psi to 15 psi is the minimum boiler pressure at rest (cold), and what the pressure reducing valve (fill valve) is usually set at. Many come pre-set at 12 psi.

Warmed up the pressure should be about 20 psi (within a few psi) and the temperature should be about 180°F to 200[FONT=Verdana]°F, which is the typical cut-out temperature setting on the boiler aquastat. See attached pics for a typical sequence of operation. Also see this site for more info …[/FONT]

[FONT=Verdana]Since the reading from the original post show 10 psi and 180[FONT=Verdana]°F something is not right.[/FONT][/FONT]

[FONT=Verdana]JMO & 2-Nickels … ;-)[/FONT]

Boiler At Rest.jpg


A new gauge is accurate but that old gauge can be anywhere between two and three psi out.
You should not call out that something is wrong.
You should recommend the gauge be removed and a new one installed.:shock:
Then check the pressure and temperature again as well.