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Recent boiler work + now High Pressure, Excess H20, and more


Last Tuesday I noticed water in our basement. It turns out the return/intake pipe to the boiler had rusted through and was leaking. So we had a plumber come in and replace a bunch of rusted pipes.

Now the system seems to be running oddly.

1) The pressure gauge on the boiler (not on pigtail - I don't have one on that) goes up to 25! (the gauge has 2 sets of numbers - Larger/top are 0-30 PSI in bold, below those in red are 0.5 - 3.0 kbar or something units).

Maybe it is measuring the lower units and not the PSI? However it is my impression that this should be showing PSI, not the bar units, but to be honest I never really paid much attention to it before, so I'm not sure.

Anyway, It then kicks off the boiler until it drops down to about 10PSI, then comes back on. The pressuretol is set to the min - 0.5 I believe. When the heat is on, it now cycles pretty quickly. It takes about 5-10 mins to reach that high pressure, then drops down in a few mins, then goes back on. Repeat. I don't recognize the high pressure or frequent cycles from being present before the work was done.

The radiators don't seem to be hissing any more than normal. There is a bit more knocking, but then it's been really cold the last few days and it did knock before in colder winters, so it may not be really new.

2) I have a small leak coming from the pressuretol - this is new. The plumber mentioned on the invoice that he did something to the PSI, but he didn't mention it to me and I can't read his handwriting...

3) The boiler seems to be filling up with water. I know there are a few leaks in the system (a few leaks on some of the radiators at the knob valves). When I checked it last night the water sight was full. So I drained some of the water and now it seems better after 24 hours, but don't know if this is another problem.

4) The radiators in the house don't seem to be getting as hot anymore. Also I cranked up the heat yesterday as it was getting chilly, and it wouldn't get too warm. Usually the thermostat is at 66 (which is being maintained by the heater currently) but when set to 70 it only went up to 68 - it seemed like it would cycle before being able to heat enough.

I called and he will be heading out today or tomorrow. He told me to shut the system off that there may be something wrong. If the pressure is really that high, could it have blown anything else in the system (eg the steam traps in the radiators? We have 2 pipe radiators - the steam goes in the top on one corner w/ a knob valve, then out the bottom on the other side). I've just learned about the steam traps today while looking into this issue. A good amount of the radiators in the house only get partly hot, not the whole thing - but that was the case already. However ones that did get fully hot aren't anymore.

Anyway, I'm just looking for some comments/understanding of what may be going on.

The house/radiators from 1920s, and the boiler is a Dunkirk from 2003.


  • Jamie Hall
    Jamie Hall Member Posts: 21,568
    Something is very much amiss

    but without starting to poke it's a bit hard to say what.  If the pressure gauge is at all reliable (not a given!) your pressures are way too high.  It really doesn't matter whether the gauge is properly zeroed or not -- the fact that it only goes down to 10 suggests that it may not be -- in either case there's too much pressure.

    Question is, why?  If the pressuretrol really is set low, it clearly isn't doing it's thing.  Bad 'trol?  Clogged pigtail?  Needs to be investigated anyway.

    Leaks don't belong.  Anywhere.

    If the boiler water level is rising, the question is -- do you have an automatic feeder?  If so, is it working correctly?  That water has to be coming from somewhere, and it isn't good either.

    There are any number of reasons why the radiators aren't heating as well as they should.  Most of them relate to the high pressure, and none of them are good.  Like vents or traps which are now paperweights  However, it will be necessary to correct the pressure first, before we can set out to find out what other problems we have here.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • petesgarden
    petesgarden Member Posts: 20

    There is an automatic feeder. When I drained the boiler yesterday it kicked on and filled it so the sight was 50% full, and it was still about that level this morning. I don't know if it was just full because of the service - maybe he manually filled it and then when the system was off once the runoff came back it was too full...

    So if the pressure was really that high (is there a way to really know?) Should I expect the plumber to replace all of my traps ( I have 11 radiators total)?
  • Rod
    Rod Posts: 2,067
    Steam System Problems

    Hi- I'm not quite sure what to tell you.  Residential steam systems operate at a maximum of 2 PSI and under. The safety valve on your boiler is designed to release pressure at 15 PSI so if in fact your boiler is reaching 25 PSI without the safety valve opening thus is a very serious problem. Believe me when a safety valve opens you will know about it!

       As this condition is a safety issue I would have a professional check your heating system  for you before you operate the system again.

    I might also suggest you get a book called "We Got Steam Heat!" that is available in the Shop section of this website. Here is a link to the book-


    It's easy, humorous reading and is written for the homeowner new to residential steam heating. It has lots of diagrams and pictures to explain all the components and what their function is. It will tell you what repairs you can do yourself and what is best left to the professional.

      You have a 2 pipe steam system which are the "Cadillac" of heating systems. It usually doesn't take that much to restore them so that they run economically and provide very comfortable heating.  You might want to post some pictures of your boiler and the piping connected to it so we can see what you have. Take the pictures from back away from the boiler so we can see and trace out the piping. We can blow the pictures up if we need more detail.

    - Rod

  • petesgarden
    petesgarden Member Posts: 20

    The plumber is coming out now so I'll see. He did clean out the pigtail and sight last week, he said maybe it got clogged and the gauge is just reading wrong - that it shouldn't have really been at 25PSI.

    I do actually plan to check out the 'We got steam heat" book. I've been in this house for 7 years and the only thing I've done to the steam system is drain the boiler every 2 weeks (run it until the water is clear). Seeing that I know know about traps and such, I may try to tackle some of those issues myself, although any plumbing projects have always been an epic fail for me. :)
  • BobC
    BobC Member Posts: 5,410
    edited February 2012
    If your boiler pressure . .

    was really 25PSI that boiler, and the radiators, should have been making some interesting noises. Pressure gauges do fail but it's good he is coming out to look things over just in case. I suspect the plumbers work stirred up some crud which is causing problems.

    Is the gauge glass water clear and is it bouncing up and down when making steam?

    Can you post some pictures of the pressuretrol (also what is the little white dial behind the cover set to) so we can see what pressure it is set for?

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • petesgarden
    petesgarden Member Posts: 20

    He is saying the pressuretrol is bad and needs to be replaced. I dunno if it was broken before or not, but given they just messed with it last week and now it's broken is ... sigh.

    The water in the sight is clear, but w/ some sediment on top, even though they just cleaned it last week. And it does bounce (about within a 1 inch range) when it is on. What does that mean?

    The pressuretol was set to the min - about 0.5 - pretty much all the way down for cut-in. I don't know what the cut-out was set to.
  • petesgarden
    petesgarden Member Posts: 20
    edited February 2012
    new pressuretrol, pressure was normal

    He installed a new pressuretrol - the old one was cracked and leaking. He said the water getting into the pigtail due to the crack (which lead to pressure loss in the pigtail) was most likely the cause of the odd cycling behavior.

    However he said the pressure gauge reads in bars, not PSI. So while the larger, bolded number is bar, the smaller font is the PSI - which even looking at it now is not how I read it but I'll take his word for it (the dial hand was at the 3:00 position). So the pressure was less than 2.5, not 25.
  • Jamie Hall
    Jamie Hall Member Posts: 21,568
    that pressure gauge

    reads in both bars and psi, and it should be very clear as to which is which.

    Can you post a photo of it taken when the pressuretrol cuts out?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • petesgarden
    petesgarden Member Posts: 20
    edited February 2012

    OK... The boiler is still having the same problem I'm concerned about.

    Here's a pic of the gauge.  I'm pretty sure I know how to read a gauge, but here's a pic:


    The inner numbers are blue - and so is the text that says: BAR 100 X kPa

    The outer numbers are black - and so is the text that says: psi

    Since the black numbers on the outside read 22.5 (it does go up to 25 before the boiler cuts off), and the 'psi' on the gauge is black, doesn't that mean the pressure is at 22.5?

    The plumber even put this duct tape on the boiler:


    This is the work I had done:


    The return from the condensation was at 'WAS HERE'.  The plumber moved it to the new location due to the pitch in the pipe (it does slant downwards to the left corner).  Also the pipe above the NEW pipe is new as well (I've added the pipe insulation to it) since that was visibly very rusted as well due to the bad pitch.

    So am I wrong about the pressure?  Is my gauge wrong? Or do I just not know how to read a gauge?

    Also, just to note, when the heat/boiler is off, the gauge is at/near 0.

    Thanks again.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,575
    edited February 2012
    Time for a new gauge!

    If the gauge reads 9psi, with the burner off, there is something wrong with it. I suggest putting a 0-3 psi gauge on so the pressuretrol can be lowered to 1.5 psi (basic function), or to 6 ounces with a vaporstat,(economy and comfort).

    The supply piping looks contrary to the boiler manufacturers instruction both in piping material, diameter, and layout.

    The installation manual is on line, and will show how the supplies/returns are to be piped, if the warranty is not to be invalidated.

    As regards the over-filling, I think the high pressure is causing water to rise in the pipes outside the boiler, so as to lower the water-line, and trip the feeder-turn off the valve before the feeder, and lower the pressure on the pressuretrol, or better yet, get a vaporstat.--NBC
  • petesgarden
    petesgarden Member Posts: 20

    If the burner is off (eg: heat is totally off) it does drop to 0.  It's just when on that it cuts out what I'm reading to be 25 on the gauge, and on at about 10.
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,144
    You Have a Problem

    Either the gauge is broken, or you have a big problem. 

    With the pressuretrol set at less than a pound, that's what you should be reading on the gauge. 

    Ten or twenty-five pounds have no place in a steam heating system.  If that's truly the pressure, you'll have high fuel bills and will ruin your traps and vents.  

    Get to the root of the problem.  I'd replace the gauge first and see what's really going on.  

    I don't know if that system ever worked properly, but the boiler is piped terribly, which can give you all sorts of problems.  How are your fuel bills?   How's the heat distribution?  If everything's alright, then you are fine.  If not, you've got a substantial bit of re-piping to do.  As Nicholas said, that's all wrong, and that is the reason for many of your problems. 
  • petesgarden
    petesgarden Member Posts: 20
    edited February 2012

    Well, I've been playing w/ the pressuretrol this am.

    It seems to sync up w/ the inner numbers of that gauge.  It's a subtraction pressuretrol, so w/ the level just below 3, the gauge on the boiler goes up to just under 2.0 (on the blue inner numbers, between 25-30 on the upper black numbers).  The differential dial is set to 1.5, and it cuts in at that point as well (about 0.5 per the inner gauge numbers).

    So is it just my gauge?  Maybe it is correct then and I'm either just reading it wrong or it is setup differently/incorrectly ?  I've honestly never paid attention to it before, so it could have always been like this...

    Here's another pic of the piping: http://imgur.com/5PBXJ

    The main return from the radiators is at the bottom.  The new copper pipe feeds off of the steam line going out of the boiler.  Before it was straight down.  Now it has moved to the joint (off the left side in this pic) on the outgoing steam line because that pipe is pitched a bit incorrectly and the condensation was pooling in that pipe and causing it to rust.

    This is how it has always been since I bought the home - 7 years.  Our heating bills are high, but seem to be on avg w/ what other people in the area are paying.

    Also. just to add, it takes about 10 minutes once the boiler goes on to reach the cut-out, then about 30min to cut back in.
  • petesgarden
    petesgarden Member Posts: 20
    Boiler: Dunkirk PVSB-5D

    That's the boiler I have. Here's a link to the manual. My piping doesn't seem too be too far off of what the manual says for a two pipe system (page 7):

  • Long Beach Ed
    Long Beach Ed Member Posts: 1,144
    I never argue...

    I never argue with someone else's happy customer.  

    The piping is incorrect on that boiler.  The way it is piped will give you water level problems because there is no equalizer.  It will give you wet steam that will cause poor distribution and high fuel costs because there is no header.   It will void any warranty and may violate local codes which would void your insurance policy protection.

    If you are happy with the way it works, great. 

    When it comes time to replace it, follow the manufacturer's instructions and you'll see that you've wasted tens of thousands of dollars in fuel and lots of comfort by living with a grossly flawed installation all those years. 
  • petesgarden
    petesgarden Member Posts: 20
    edited February 2012

    As I said, this was the way it was when I bought the house, my first time w/ steam, so I really don't know anything better. The plumber I'm using isn't who installed the system, and didn't say anything related to the header.

    So what's the header that I'm missing? In this pic:


    The steam comes up on that yellowish pipe (it's stuck insulation from a sleeve that was on it before I had the servicing done.). It then curves left and goes for about 5-10 feet. Then there is a T, it goes up to another pipe, which then Ts again. Sorta like this (just showing steam output pipes):

  • petesgarden
    petesgarden Member Posts: 20
    back to pressure

    Ok - I know that my pipes may be setup bad, and a million other things, but I'd like to get the pressure issue resolved as I'm worried the whole thing is gonna blow up.

    I have a new pressuretrol from yesterday. It is safe to assume that is working correctly and regulating the pressure?

    I think the gauge must be bad. The plumber told me the inner units were PSI, but that just seems wrong to me.

    If I were to install a low pressure gauge, is that an easy do-it-yourself task? What is required - any welding or just piping w/ teflon tape? Do I need to worry about air in the system, etc?
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,144
    Pressure Gauge

    Pressure gauge is threaded.  It screws on clockwise with a small amount of pipe threading compound or Teflon tape.  If the boiler is off and cool it will have no pressure in it.  Use an adjustable wrench to hold the square boss on the back of the gauge when you screw it on.   Sometimes the boiler jacket gets in the way of your wrench.   Sometimes you need a very thin wrench like a bicycle wrench.   If you twist the body of the gauge with your mitt you will probably break it or at very least mess up the calibration. 

    Maybe you can do this, maybe you can't.  It depends on your level of mechanical skill. 

    Most every code requires a gauge that displays 30 psi for a steam system (twice the allowable pressure).  The problem is that with that gauge you usually see little if any movement at the regular operating pressure of about 1 pound. 

    Many people use lower pressure gauges for their convenience, so they can see what the system is actually doing, though the omission of a 30 pound gauge would certainly jeopardize their fire insurance.  Since your boiler is piped the way it is, this isn't a worry; it's not insurable. 

    Let me add this:  There's a big difference between 1 pound and ten pound steam.  If you open the relief valve at one or two pounds of pressure you should see some lazy steam like what comes out of a kettle.   If you open it at ten pounds it looks more like a scolding power washer that would fill the basement with steam in seconds.   Just don't burn yourself.

This discussion has been closed.