Loud hissing from nearly all radiators during this cold spell

Trying to make up 4 degrees in Zero degree weather is something you should avoid doing .. you want to maintain your temperature, not increasing it 4 degrees daily and letting the home cool down 4 degrees at night.. especially at Zero degrees

I do that. My contact info is below

Not sure if these issues are related.

Yes, they are related

from here, I would first verify the pressure regulation was working

Then if vents are leaking under normal conditions, they have to be replaced

All the manufacturers supply a 0-30psi gauge because it is code that the gauge must be rated to twice the maximum operating pressure of the boiler (I have been told). The pressure relief valve on a residential steam boiler is at 15 psi so that's why the gauges are always 30psi.

If you doubt the pressuretrol, then it would be good to purchase a low pressure gauge to put in that spot (temporarily) or in another spot (could be permanent) to see what the actual operating pressure is when you are hearing the hissing.

Then you'll know if you the vents are bad, or if the pressure is just too high.

I will add that your boiler water is extremely dirty and although I am not a fan of unnecessary draining and refilling, in your case I would consider it necessary.

I don't know why the link is no good. Trying again:

https://www.youtube.com/%40gordonschweizer5154

https://www.youtube.com/@gordonschweizer5154 /search?query=pressuretrol

Go to youtube. search on Silent Steam Team. Go to "videos". Search on "pressuretrol". That should get you to the ones for your pressuretrol.

We need more pictures. Front, and other side of the boiler, showing all the piping going out of and into the boiler.

Better picture of the pressuretrol, closer up and in focus, with and without the cover (only one screw to remove cover)

Can't tell what I'm looking at with your boiler piping photos. Need pictures a bit further away and from multiple angles. But, it looks like your header goes into a bullhead tee with one side going up to the main and the other becoming the equalizer. That would be super wrong.

We need photos of the other side of the boiler showing the Hartford Loop. Measure with a liquid level (clear tube with water in it and a helper) or something, from the top of the Hartford Loop close nipple or elbow to the normal water line of the boiler (should be marked by manufacturer)

We still need that crucial photo of your pressuretrol with the cover off (remove one screw at the front bottom), showing the internal dial setting. It looks like your cut-in may not be as low as it could go.

That radiator valve is not working in the off position probably just old.

bob

Did you watch the video? If money is not an object sure but plumbers are crazy expensive. It is a pretty easy repair. It is really a handyman friendly job so you wouldn't have to hire a plumber and pay the trip charge and all that.

Probably better off opening it back up because it may be acting as a one way valve, letting steam in but not letting condensate back out, except for the vent. On second thought, if you want to keep it turned off for now though, I'd remove that vent and put a plug (pretty sure it is 1/8 in. NPT) in it's place and keep the valve closed until you can replace that valve.

Yes any supply valves that are hissing or leaking are bad and need to be repacked or replaced. Any vents that continually hiss after steam has already reached them are also bad and need to be replaced. If steam has not reached the radiator vent yet and it hisses it is just releasing air from the radiator as steam advances and the hissing in this case would be normal if the pressure is much more than a couple tenths of a psi.

I don't know what your overall connected sqft of radiation is relative to your 746sqft of boiler rated steam capacity but if your boiler is at all oversized you have to make adjustments for extreme cold weather. I have a 35% oversized boiler yet most of the winter am able to do 5 or 6 degree setbacks and recoveries without issue because I manage those recoveries broken up into controlled on off cycles that limit continuous firing time of the boiler thus avoiding pressure rise. Pressure only rises in the system as radiators one by one start to completely fill up since then there is less place for the steam to go and the boiler doing what boilers do continues to make the same amount of steam until either the thermostat, the pressuretrol or the low water cutoff tells it to stop. So, to avoid all this in extreme cold weather think about what you can do to avoid all or most of your radiators completely filling and thus building pressure. Answer:

1. Minimize the required heat - Lower or eliminate your setback if weather is going to be extremely cold. Only you can define what extreme cold is for your system based upon your experience. I am one of the few proponents of setback on this forum but where they do save me money on normal winter days, once night time temperatures get below 15 degrees or so they don't do anything for me but make morning recoveries noisy. If your system only needs to raise the home temperature a degree it is going to take less cycle time than 2, 3 or 4 degrees. I normally go from 59f to 66f but last night and the night before here in Michigan I just set the temp on hold a 65f and went to bed… (-14F this morning)
2. Run more shorter cycles - Setting your pressuretrol or vaporstat lower will do this to some extent but they are both still reacting to some level of pressure rise which indicates you are already running a longer cycle than optimal. One simple thing most people can do depending upon your thermostat is to adjust your thermostat control to help minimize cycle time. If a cycle per hour type setting then set it for the cold snap on 2 instead of 1. If a swing temperature range type control set it on +/- 0.5 degrees instead of +/- 1 degree. You can always switch it back if you care to after the polar vortex has passed.

When it comes to the main venting it looks like you have a Gorton #2 on each main which may be sufficient. Have to know your total steam main lengths and pipe sizes to know for sure. Where more main venting makes the most difference on a system is during extreme cold snaps because most of the heating cycles start off with very warm steam main piping and thus the rate of steam advance is less hindered by condensation in the mains themselves from heating up the mains. This isn't going to change your late cycle hissing though, only any hissing that may occur early in the cycle after the boiler starts creating steam and before the main vents closed.

If you don't have a low pressure gage there is no way you know your pressure trol is not working. Vents will start hissing at more like 0.5psi. It doesn't take 1.5psi to make them hiss particularly if your boiler is oversized or it is after a few radiator vents have closed.

Yeh, my 0-30 gage doesn't move even when when my true pressure reaches 1.5psi. I verified this when I was tweaking the settings of my pressuretrol.

@dabrakeman ok so if my gauge is worthless what, if any functionality, should I see from my pressuretrol? Should the normal cycling operation take the system pressure from 0.5(1st heat cycle start) to 1.5(1st heat cycle stop/temp not yet reached) back to 0.5(2nd cycle start) back to 1.5(2nd heat cycle stop/temp reached) etc or something like that. It shouldn't just run the entire time until the intermittent low water check stops.

I have a #2 at the end of my 'red' line. I addressed this when we moved in with the help of the forum (https://forum.heatinghelp.com/discussion/201019/need-help-balancing-steam-system). I need way more venting on my 'red' line because it's much longer than the 'blue' line. So i tried to balance this with a #2 at the end of the red and a #1 at the return so the steam wouldn't wrap around a trap the red line. As you said it would be quite the expense to repipe this.

I can't get an accurate measurement of the height from the hartford loop close nipple to the water line because the indicator is opposite the loop. My guess is it's between 1" and 2". I looked at the utica manual for my model and figured it was ~2" and then said it doesn't really matter because I'm not repiping s*it. We don't really get any water hammer fwiw. Thanks again.