gorton #2 vents issue

EzzyT

I installed Gorton #2 vents 6 in total 3 on each dry returns. The mains run about 12' feet from the boiler and the returns back to the boiler. It seems that the vents are heating up beyond there temperature capacity and shutting closed which in then is causing pressure to build up in the system I'm just trying to fig what I can do fix this issue any info will help and be much appreciated

nicholas bonham-carter

Vents causing over-pressure?

The vents will let cold air out of the system, as the steam is rising. When the steam reaches the vents, they should all close.

The job of the pressuretrol, or vaporstat, is to cut off the burner, when the pressure rises to the cut-out point. With no heat, the steam will condense, and lose its pressure, whereupon, at the cut-in point, it will make the electrical contact which fires the boiler. If your boiler is properly sized, then the on cycles will be continuous, until the thermostat is satisfied. If the boiler is too big for the system, then it will cycle on and off, until the temperature is achieved.

Gortons do better on long antlers which will allow them to cool down in between cycles.--NBC

EzzyT

boiler is properly sized.

The pressuretrol cut in is set at .5 psi and cut out at 1psi boiler still stays on building pressure to about 3.5 psi and then turns off. It doesn't have that continuous cycle like it should. I have the vents on a manifold off the returns up 6" and out 6". Is that far enough? As seen in the picture.

MDNLansing

Pressuretrol

How old is the pressuretrol? Some old ones won't mechanically allow for anything less than .5 and about 3 psi. If you have an older one, this is probably the best you can do.



As for the vents, they are doing what they are supposed to. They vent to cool air, then close when steam reaches them. They aren't supposed to let steam flow through them to regulate your pressure.



How long does it take from the boiler first firing until it reaches 3.5 psi and the pressuretrol shuts it down? Once it shuts down, how long does it take for the pressure to fall to .5 and fire back up? Depending on these two intervals everything might be just fine. The boiler cycling on pressure is a normal operation for some designs and can actually be pretty efficient.

EzzyT

boiler a year old

i replaced the boiler last year at the end of the heating season. so its a new pressuretrol. it takes about 35-40 minutes to reach 3.5 psi and about 10-15 minutes to drop down to .5psi.

Hap_Hazzard

Pressuretrol

The pressuretrol is set where it should be, so if it's not cutting the burner at 1.5 psi, it's either wired wrong or it's not seeing the pressure. If you can open the case and pry the end of the rocker up with a screwdriver while the thermostat is calling for heat and the burner is firing, you should hear a click from the switch, then a louder one from the gas valve, and the burner should shut off. Release the rocker and the burner should resume firing. If the switch clicks but it doesn't shut off the burner, it's not wired correctly. If it does, it's not seeing pressure.



The most common problem is that the pigtail (technically it's a steam trap or siphon) on which the pressuretrol is mounted becomes clogged and won't allow pressure to reach the pressuretrol. This is especially common with steel pigtails. It's possible to clear the blockage in a pinch, but not worth your time if you can buy a new one.



If the control is wired correctly and the pigtail isn't plugged, the next possibility is that the pressuretrol is way out of adjustment. Get back to us if that's the case and we'll take it from there.

EzzyT

boiler piping

3" drop header with 11/2" equalizer

Jamie Hall

Those vents

are as has been said doing exactly what they are supposed to do.  I see one problem, though -- the cutout pressure is too high.  Assuming your gauge is accurate, you might try working with the pressuretrol some more -- but it's not unheard of for them to be off calibration.  Not, however, two pounds off as yours appears to be.  Problem is that that much pressure is not good for the vents; they probably will survive, but they are not liking it much.



Gortons -- like most vents -- will close when they reach near steam temperature.  That's exactly what they are meant to do.



I might enquire... how is steam getting to those vents?  If they are on the dry returns, there should never be steam there.  Bad trap(s)?  If there are orifices, the high pressure is causing blowby...  but unless this is a Hoffmann Differential Loop, they should never see steam on a dry return.

EzzyT

pigtail

i just cleaned the pigtail when doing the boiler start up im thinking in the same lines that you just said that the pressuretrol could be out of adjustment.

EzzyT

dry returns

yes they are on dry returns you could see them in the pictures i posted

nicholas bonham-carter

2-pipe or 1-pipe?

I am assuming that you have a 1-pipe system, with an inaccurate, or unsuitable gauge-is that right?

These systems only use ounces when they are in proper maintenance, so you must get a gauge able to measure that pressure, and a vaporstat to control the boiler at those low pressures.--NBC

EzzyT

one pipe

yes you are correct about the gauge ordered a 0-3 psi gauge none of the supply shops i deal with have any in stock so waiting for the new one to come in. i am going to install a maxitrol 2 stage gas regulator with vaporstat for hi and low fire

nicholas bonham-carter

Over-sized boiler

A boiler of the correct size should not be able to build that much pressure.--NBC

EzzyT

sized correctly

i sized it correctly that was the first thing that came to mind but i doubled and tripled checked it. really confusing ill just have to see what happenes once i change the pressuretrol and install the vaporstat and the two stage regulator

MDNLansing

Curious

I am curious about this statement NBC. This is my ignorance, not a disagreement with you. Why would a "properly" sized boiler not be able to reach 3 psi? Wouldn't any size boiler have the ability to continually build pressure well above 3 psi? I realize that as steam is being generated it is also condensing, but I would think that even the smallest of boilers matched perfectly in size could steam faster than the steam would condense.In the initial parts of a long run I can see this happening, but once all the pipes and components are at maximum temp, wouldn't condensing slow, allowing the steam to continue to build?

nicholas bonham-carter

Boiler matched to radiation

Some lucky people here have boilers so perfectly matched to the load, that all the steam is condensed as fast as it is generated, and therefore have no pressure beyond a few ounces in their systems.

Your boiler seems to be capable of making a bit more pressure than is needed, so the pressuretrol, (or better yet a vaporstat) is needed to cut off the burner as the upper limit is attained. Maybe you haven't yet had the colder weather which would condense all the steam.--NBC

Hap_Hazzard

Pressuretrol Adjustment

First make sure the two screws holding the switch are tight. If the switch is loose, push it down all the way and tighten the screws.



Next, get a .005" hex key. Find the adjustment screw on top of the rocker assembly where the actuator from the diaphragm meets it. With the boiler off and at zero pressure, turn the screw clockwise until the switch opens. This is the cut out point. Now turn the screw counter-clockwise, very slowly and without putting any pressure on the rocker, until the switch just closes. That's cut-in, and you've just set it as close as you can get to zero.



Now fire up the boiler. Watch the pressure rise and make sure it cuts out at or near the cut-out point (cut-in + differential). As the pressure drops, it should cut in at 0.5psi. If it reaches 0.5 and hasn't cut in yet, turn the screw counter-clockwise again, as before, until the switch cuts in and fires the boiler. (If you have an automatic damper it may just activate the damper motor, and the burner won't fire until the vent is open.)



Monitor the switch operation through at least one full cycle where the cut-in and cut-out occur at the appropriate pressures.

Bio

Matched

I may be lucky, my boiler runs at 1oz or less, from cold start it runs 45 mins to 1 hour uninterrupted until t'stat is satisfied, it only heats up top third of radiators, steam never reaches the air vents

EzzyT

old boiler

The old boiler was way over sized so I took my time to do a proper heat loss. I'm in the NJ area so its been getting pretty cold at night. I'll try to calibrate the pressuretrol and maybe increase the radiators vent too. Once i get the 2 stage maxitrol gas regulator I'll instance it with vaporstat and see what a difference it is.

steamedchicago

pressure

A perfectly sized boiler makes steam at the same rate its condensed by the system at the design temperature (probably 0F for NJ), so it will have no pressure at all. The world isn't perfect, of course, and so you'll get some pressure, particularly after the piping has been heated up and that source of heat loss goes away.



Single pipe systems need to be sized to the attached radiation, not to the heat loss. The attached radiation can be sized to the heat loss, of course, and probably was when the system was built, but change happens. Windows are replaced with better ones, insulation gets added, radiators are removed...



What's the boiler's rating, and how much EDR doe it have attached to it?

EzzyT

boiler

Boiler is sized for attached radiation load. Input 150,000 output 125,000 net ibr 94,000

Edr about 90,000