Steam and bubbling water coming out the main vent

jessestaton · January 26

We have a 1920s vapor system on a gas boiler.

Vaporstat and a Pressuretrol that is supposed to be a backup.

Was getting really loud hammering and loads of steam and bubbling water coming out the sole main vent. (2700 sq ft four square style home).

The expert we use is backed up due to the weather. Only 3 radiators have conventional traps, the rest are original water traps. Almost all.but maybe a ceiling radiator in the basement have orifice plates. I thought steam must be going straight thru a radiator or two to get steam out the vent so I made sure all un-trapped rads had orifice plates. I closed the suspect ceiling rad.

My pressure gauges read 0.

Next I took off the gauges and controllers and cleaned the pipes. Couldn't get the pigtail off (and didn't have a spar) but I cleaned with a wire at least to where it goes horizontal and poured water in and it drained.

Reassembled with tephlon and Oatey white dope.

Now the gauges show pressure.

Pressure is going up past 35 oz/in2. The other gauge shows 3 psi.

Still banging, venting steam and bubbling.

Positive note, the gauge shows 1 psi vacuum when the boiler is off.

Suggestions?

Maybe I put too much dope and obstructed the vaporstat?

Jamie Hall · January 26

Possibly. That vapourstat should shut off at 5 ounces, and they are pretty reliable.

jessestaton · January 27

Vaporstat was not obstructed. Pressuretrol wasn't either. Pressure gauges were bouncing.

The steel pigtail broke off with a little tapping and a little torque.

Now what?

Best methods for getting that out?

Drain first, penetrating oil or no?

Utica boiler PEG262CDE from 2006

jessestaton · January 27

Harbor Freight screw extractor worked. It'll be a cold night but ill sleep better knowing now all I need is a new pigtail in the morning.

EBEBRATT-Ed · January 27

Just stick the vapor stat on with a 1/4" nipple and elbow. Not having a pigtail for one night won't harm the control

Just make sure the control works and the boiler stops on pressure. For some reason you pressure is too high causing your issues.

jessestaton · January 27

Too bad I didn't see this until the morning.

jessestaton · January 27

New pigtail is on, had to add a nipple which made the wiring a harder fit.
Boiler is back to boiling.

System is a 1920s vapor system with mostly original water "traps" (which are really more of a vacuum holder for the condensate line)

Still getting lots of steam coming out of the main vent.

System is still in the process getting the house back up to temp so cycling constantly.
I have no one to run this by so hopefully The Wall can give me some feed back.

Questions:
The Vaporstat is designed to break the connection between the Line and the Load when the pressure reaches the Main setting. (in this case about 4 OZs/IN2) - Correct?

The Pressuretrol (PA404A Additive Diff) is also designed to break the connection between Line and Load when pressure reaches the setting (set near 0.5 PSI). - Correct?

There is a remote temp sensor installed on the main line out near the main vent (about as far from the boiler as possible) that is supposed to allow the boiler to continue to fire until the main gets to a certain temperature where the sensor is installed (to reduce short cycling).
That should mean the temp sensor is Making the connection until the desired temp is reached, then Breaks the connection to allow the Vaporstat to manage the boiler. - Sound right?

Boiler is shutting off at what could be 45-50 OZs/IN2 on the small gauge and about 3 PSI on the big "useless" gauge. Seems to be in the ballpark of 16oz per PSI.

Question is: what device is cutting off the load at this point and why is the Vaporstat not keeping the pressure at 4 OZ?

Does it make sense that the remote temp sensor has failed and is not "Breaking" the connection when temp is achieved? Thereby continuing to over-ride the Vaporstat until the Presuretrol takes over?

Photos
Line is connected to Vaporstat "R" terminal
Load is connected to Pressuretrol "Left" terminal (I can't find a diagram or label for the Pressuretrol terminals)
Remote Temp Sensor is connected to Vaporstat "R" terminal - therefore getting Line current. and also connected to Vaporstat "B" terminal (if sensor failed in a closed position - transferring Line to "B" terminal constantly)
Vaporstat and Pressuretrol are connected by a double/joined black/red wire (twisted together) from Vaporstat "B" to Pressuretrol "Right" terminal.
If Remote Temp Sensor has failed in a closed position - Line power is then being transferred from Vaporstat "B" to Pressuretrol "Right" terminal. (if failed is closed - which seems odd but possible)

I disconnected the Remote Temp Sensor.
Boiler is cycling on and off when pressure reaches 45-50 OZs/IN2.
Seems like the Vaporstat is not working and boiler is being governed by the Pressuretrol - Sound right?

I am still getting steam coming out of the main (only) vent.

How is steam getting to that vent? The vent is only connected to the Condensate return.
Does this mean that steam is passing completely through one or more radiators and entering the Condensate line? Seems like the only way.

neilc · January 27

you have too many wires on the Vstat,

and the Ptrol, is that forked connector on/or off it's screw? a clearer picture there(??)

the Vstat, what's the second pair of wire doing? nothing in the control / safety circuit should be wired parallel, it should be series wired, one wire in, one wire back out, to the next safety/control device in the circuit, or draw out and post what's doing there,

and if you have a remote sensor, keeping the thing running, loose it, that's why your Ptrol / Vstat aren't controlling pressure,

4GenPlumber · January 30

Agreed, by wiring a remote sensor parallel, you are giving the circuit a route to bypass the vaporstat. Take out the remote sensor(send Pic of sensor anyway).

4GenPlumber · January 30

Sorry, you already said you did that. To test, eliminate all redundancies. Use vaporstat as your only pressure control, fire the system. Stay and watch. If it passes the cut out, you have your answer. Disconnect one lead if it passes, you may have other bypasses wired in to your burner circuit (dont know why, dont understand the remote sensor either though).

jessestaton · January 31

New vaporstat installed set to 4 oz.

Boiler shuts off at about 8 oz on the gauge (way better than 35+ oz.).

Not certain which is more accurate, Vaporstat or gauge but it's probably not worth buying a new gauge to compare. No more steam escaping from the vent.

The remote temp sensor is a button cell battery looking thing clamped to the bare metal on the main on the other side of the house. It breaks the circuit when it's temperature is met. When it's below it's temp, the circuit is closed allowing the line voltage to get to the boiler, bypassing the vaporstat but not the Pressuretrol.

Once temp is met and the circuit is broken, the vaporstat is managing the boiler with the Pressuretrol in line as a backup. This setup prevented lots of short cycles while the system gets up to temp and most radiators got steam.

Apparently the pigtail/steam siphon was plugged. I have no idea what was shutting off the boiler. Maybe some steam pressure was getting to the Pressuretrol but not as much as was actually being generated.

Pressuretrol was still working but not ideally as some lower pressure steam was still exiting the vent. I set it as low as possible after the new pigtail. I still think I have a ceiling radiator without an orifice but there is stuff under it which makes it hard to get to and open without getting stuff wet. Plus I don't have an orifice to put in right now.

Now it's running fine.

After reading the boiler manual I see manufacturer recommends blow down cleaning once a month during operating months. Gee, how many people do that? I have not figured out how to get boiling water safely from the boiler drain to my floor drain. Schedule 80 PVC? Copper??

ethicalpaul · January 31

No, don’t blow down your boiler once a month. You want to minimize adding water.

Steam and bubbling water coming out the main vent

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