Utica Starfire 3 boiler - high psi

Hello - We have a Utica Starfire 3 oil furnace (steam heat). Over the last month the pressure gauge has been steadily increasing. Today its at 8 psi and the furnace isn't even on right now. We have a cutoff switch which will be tripped if it goes any higher. We empty the water in it weekly (its always dirty) and then slowly refill it to the correct point. The furnace was cleaned about a month and a half ago. Its approx. 3 years old.

Anyone have any thoughts on this?

Thank you!

 

There are several possible causes for your high pressure problem. The first, one of the most common, & easiest to fix is a faulty gauge. Allow the boiler to cool completely & check the gauge.

How much water is in the sight glass? At 8# the boiler would be flooded & you could have a water feed valve not shutting off completely.

If the above checks yield no results, I suggest calling your servicer. It could be the pressure control & they should be installed by someone familiar with steam systems.

 

Hi - Thanks for the reply. The furnace has been off for several hours and is completely cool, but the pressure gauge is still at 8. The water level is just about halfway up the sight glass. Should there be a siphon between the furnace and the gauge? There's a siphon just before the pressure cutoff switch, but nothing between the furnace and the gauge. Just wondering if this is a problem (picture attached).

http://i216.photobucket.com/albums/c...e/IMG_3629.jpg

If its a faulty gauge, then it should replaced by a professional, correct?

Thank you!

 

If the boiler is cold, it would be safe to replace the gauge yourself. Just to be sure there is no pressure, open the relief valve manually.

Some boilers have siphons between the boiler & the gauge, some do not. This would appear to be factory installed so I would not be concerned with a siphon.

 

What is that control next to the gauge set at ?

 

Thanks Grady

NJTrooper - the control next to the gauge is set at a little over 8. I believe this is the cutoff switch to turn the system off if the pressure gets too high. So far it hasn't turned off due to the high psi reading.

 

I know next to nothing about steam, so anyone correct me if I'm confused...

I thought that control was used to adjust the pressure that the boiler operates at, not as a 'high limit' ? Am I wrong ?

If that's not the control that does that, which one does ?

 

Trooper,
You are correct. Unless there is another control we can see, that would be the operating control. Eight psi in a residential boiler is WAY high. Normal would be 1 or 2 psi, but I'm no steam wizzard either. Let's ask Furd.

 

The way that low water cutoff is piped the possibility of allowing steam to the gauge certainly exists. Also, the way the siphon is installed on the pressure control is incorrect if that control uses a mercury switch.

As the siphon heats it will have a tendency to "untwist" and that will cause the pressure switch to tilt and change the calibration if it is the mercury switch type. The pressure switch must be mounted level (side-to-side) and to maintain this the loop of the siphon must be parallel to the side, not the face, of the switch. Removing the cover will reveal if it is a mercury switch control and if so it most likely has a pendulum level indicator on the inside back wall.

I would replace the pressure gauge and install a siphon OR repipe the gauge / switch using the siphon first and then tees and elbows as necessary.

Grady is absolutely correct that the operating pressure of residential one-pipe steam systems should never exceed 2 psi and they often work best with only 1/2 psi. If there is not a manual-reset high pressure cutout (my preference) in addition to that pressure switch then that switch needs to be reset to cut out at 2 to 4 psi.

Don't forget that steam boilers need to be periodically "blown down", that is, drain a quantity of water from the bottom drain of the boiler as needed to prevent a build up of "crap" (that's a technical term ) due to the evaporation of the water. How much and how often will depend on the quality of the feed water and how much water is added.

Also, it is necessary to periodically blow down the low water cutoff and the gauge glass to keep crap from accumulating.

 

Hello - I wanted to thank Furd, NJTrooper and Grady for helping me out with this issue. I meant to post an update awhile back but time got away from me. We wound up having to call a technician on 12/23 because the furnace finally shut down due to the high pressure. It turns out that the siphon pipe had accumulated a lot of rust and other gunk and that's what was causing the high psi reading. The tech cleaned out the pipe and lo and behold the psi went way down to barely over 0. He said the long term fix is to move the pressure gauge to a different location where its above the water line. For now its working beautifully. Just wanted to post this in case someone else has a similar problem.

Thanks again everyone!