Can't get 3 psi gauge or vaporstat to work

1dodson

My recently purchased house has a two pipe steam system and an old boiler with huge gas bills from last winter.  I bought Dan's book, tried to educate myself and decided to try a vaporstat .  The original pressuretrol was tapped into a port on the ITT water level control and only had a 30psi gauge.   I replaced the pigtail, presuretrol with the vapor stat and added a 3psi gauge.  I turned on boiler, all the radiators got hot, but nothing at the 3psi gauge. 



The port on the ITT water level didn't make much sense so I moved this all to the 1.5" port above and added a bunch of reducers to get to 1/4". (its all they had a home depot).  The radiators get hot but once again nothing at the gauges except a little flutter.    I unscrewed  a gauge and steam came out but I still can't get a reading.



Any suggestions?  

Rod

Check out the gauge and openings.

Hi- 

Interesting dilemma!  Questions: Did the 0-30 PSI gauge operate before you changed the piping? When you removed the gauge, did the steam come out with some force?

The only possibilities are either a bad gauge or a blockage in the piping, or you aren't making steam (that's why the question on "force") The radiators could still might get warm though it would take much longer.

If you blow on the 0- 3 PSI gauge, does it register? I would make sure the pigtail and the piping is open. There maybe some teflon tape plugging it or something like that . I would also make sure the port you changed over to is open all the way into the boiler. With a flash light you should be able to see into the boiler and also run a coat hanger through.

To check that it is making steam you should get some up and down movement of the waterline in the sight glass. If the waterline is very still then you may not be making much steam. You also can usually detect this in how fast the water comes out the LWCO when you use the blow of valve.

If nothing else works you could always move it back to its old position on the LWCO and try that!

Just some thoughts.

- Rod

1dodson

Checklist

The 30psi gauge always showed zero in the old position but I just assumed it was due to inaccuracy, which is why I purchased the 3psi gauge, and moved this to a more logical position.  (who knows what the old homeowner did.  I was also concerned that the unit never cycled on pressure, which is why I changed to the vaporstat.



The 3psi works fine when I blow into it. 



Steam comes out when I remove the 30psi gauge but I can't say its forceful.  I checked this port and it does go right into the boiler.   Also, I blew through the hole where the 30psi goes to insure the pigtail is clear. 



I do get some movement in the waterline on the site glass but probably no more than an inch or so.  



Maybe this is a stupid question but could this be a vacuum system?   

jpf321

your boiler is properly sized

condensation matched steam production..don't expect much pressure build. my new unit takes 2 hours before pressure build. I'm happy and so should you be. most people have an oversized boiler and hence much discussion on pressure.



if you really want to see it work, go around and shut off several or all of your rads. otherwise just be happy.

BobC

fooling the system

If the input valves to your radiators work, try closing all of them, that will remove the load from the system and you should be able to build pressure. If this is single pipe steam you could also try turning all the radiators air valves upside down (or replace them with 1/8" threaded plugs), that should mechanically close all the vents and also remove the load from the boiler.



After doing one of the above turn up the thermostat and monitor the boiler and gauges. the boiler will build steam and fill the mains but the steam will have no place else to go. You should be able to verify the gauges and the setpoint of the vaporstat.



I suspect your boiler may be very well matches to the connected load so you never build any pressure before the thermostat is satisfied.



Bob

Rod

Balanced System

Hi- Okay, well if everything checks out, as JP says, you may have a well balanced system. You might try what he recommended on shutting off a few of your radiators which would make the boiler oversized. It should then build pressure which will allow you to determine on the pressure gauge where your vaporstat actually cuts out/in.

 Do you have traps on the exit pipe on each radiator? If so have you checked each of them out?  It concerns me as to why your fuel bills are high and bad traps can be a cause of this.

- Rod