Radiator Vent Noise when heat is off

Matt722

On 3 rads (2 Gorton 6, 1 Gorton 5)I get loud whooshing noises when he heat isn’t turned off. My understanding is this is air intake into the rads because if the vacuum created when steam collapses. I don’t u sweat and why it happens on certain rads. The coils aren’t even all fully heated. Any way to eliminate the noise or at least get the main vents (Gorton 1 and 2s) to break the vacuum?

Fred

What pressure is the system running at? You hear it at those radiators because they are the ones that open first, after a heating cycle. Do you have enough main venting? You may be able to add a vacuum breaker on one of the mains, where the vents are.

Matt722

Pressure is set at 1 or 1.5. It’s the Mercury pressuretrol that only indicates 2 as its lowest and I have it set halfway below 2 and lowest it can go. Sub Diff is at 1ish.

How do you know if u have enough main venting? I have Gorton 1 on the main in question that services 3 rads. This isn’t the longest main run. That has Gorton 2 servicing 3 rads with 2 large ones. One small run servicing a single large rad has Gorton 2 as well.

What is a vacuum vent and what is correct way to place and install it? Thanks!

nicholas bonham-carter

You should rarely hear the air escaping from, or rushing back into the rads, if you have adequate main venting. Your fuel company loves that sound, when it happens, because it is the sound of extra fuel they can sell you. If the steam can fill the pipes 5 minutes more quickly on every cycle, then that is less total runtime every season.
If you had a low pressure (0-3 psi) gauge, you could be sure the pressuretrol was honestly controlling the pressure. You could also see whether the main venting was adequate, by observing the backpressure of venting, as steam just starts to push the air out of the system. Bigger vents on the rads alone will not solve the problem.
Generally, the Gorton #2 will handle about 20 feet of 2 inch supply, while for the same price, a Big Mouth will handle 50 feet, for the same price. In addition, the vacuum relief performance is better.—NBC

neilc

That mercury Ptrol,
you know it needs to sit dead level for accurate control, correct?
There should be a indicator pendulum inside on the back of the case, or check it with a small level across the case top.
Its pigtail should orient front to back, not sideways, so expansion / contraction doesn't affect the Ptrol case level(ness?)
And is your pigtail clear?
Are you sure your main venting is adequate and working?

mikeg2015

One challenge is that the best main vent, the big mouth, once closed, will not reopen under vacuum until it cools off due to it’s design. I’ve added a seperate vacuum vent, but its cracking pressure is too high.

On vapor systems, the piping volume is large compared to the amount of radiator venting, so a deep vacuum forms quickly. These systems were designed to operate under a vacuum and use very slow venting Hoffman #2 vents on a modulating coal fired system that ramped up slowly and cooled off slowly.

I still don’t have a perfect solution. I may just need to use some extra toppings and add some Gorton D or MoM D vents.

Matt722

Yes the ptrol has been cleaned cleared and is level. All main and rad vents are new.

I had a Big Mouth on the longest main and it never closed properly and so it leaked steam. Didn’t start out that way. Tried 2 different ones in fact coz I read on here how some were defective but for mine well after issue was resolved. Reached out to the company but they said it was normal flash steam. My boiler was constantly refilling. Switched back to Gorton 2 and no more issue. My longest main is 40ft total. To be honest didn’t notice a time difference between the two but you are right 5min compounded over a season adds up.

The main giving me issue has a Gorton 1. Its 20ft long. I should switch to a 2.

So to be clear is the consensus that the main venting breaks the vacuum and not the rads? Or that whichever vent breaks the vacuum there should be no noise and noise is caused by inadequate venting?

Fred

I would say whichever vent opens first will be the one that will suck air and has the potential to have a little hissing sound. Having said that, typically, with radiators usually being oversized for the rooms they are in, in most cases, all of the radiator vents shouldn't be closed because steam probably never hits some of them and the system shouldn't suck air, unless you have vented each radiator so aggressively that they all fill to the max. Is that the case? Do you have some rooms that over heat? If so, try using slower vents on those radiators and I suspect the hissing will go away. Remember, the goal is comfortable room temps, not full radiators.

Matt722

Yes I will try to vent these rads slower. They are out of balance but it’s done to get even heat. Some rooms are colder than the tstat source and trying to get even heat.

The rads aren’t heated fully though to make the vacuum break sound. There’s a coil still cold. I used to have hissing and whistling sounds on startup but no longer once I skimmed and lowered the pressure. I will try to get a 0-3 gauge installed to be sure if pressure.

gfrbrookline

I would add Gorton 4's to the rooms that are warmer to redirect the steam to the cooler rooms. My system is much larger than yours and my radiators are vented with ventrite #1's set to no more than 4, Gorton #4's and 5's. I used to have Hoffman 40's, Gorton 5's, 6's, C's and D's but learned that venting the rads slower actually made them produce more heat and evened the building out to within 1 degree. You need to mass out the main vents and add slow vents on the radiators to add resistance so the steam can fill the mains first and allow them to feed the risers evenly.

ethicalpaul

My largest upstairs radiator (bedroom) sucks a lot of air through it after heat cycle ends, but that makes sense cuz it’s a MoM #6 and the other 3 upstairs are #4, so it’s probably doing the inhaling for all of them. I’ll figure something out when I repipe it, like a riser vent etc

Matt722

@gfrbrookline said:
> I would add Gorton 4's to the rooms that are warmer to redirect the steam to the cooler rooms.

That’s exactly what I did with the rad in the room with the tstat. The rooms making the vacuum noise have Gorton 5 and 6s. Think I’ll reduce them all to 5s and increase the main vent for this run. Thanks everyone!

gfrbrookline

@Matt722 You have gone through 2 Big Mouths and they have both failed. Can you post picture of where they are/were mounted. They often fail if they are mounted in the wrong place and are subjected to water.

Also what is your ptrol set to and do you have a 0-3 gauge to confirm the setting?

What you are describing sounds like under vented mains, over vented radiators and a mis-calibrated Ptrol.

gfrbrookline

looks like we wrote over each other but are on the same page to solve your issues.

gfrbrookline

Instead of buying Gorton's of multiple sizes to play trial and error to balance things out I would go with Ventrite #1's. They are adjustable and will save you money and headaches.

gfrbrookline

There is a huge difference between a Gorton 4 and 5 the Ventrite #1 fills in the gap.

Fizz

Make sure you know what mains supply what rads before changing the vents; if a main supplies rads that are all warm then that main may vent too fast, and vice versa. If they're mixed then change where needed.

PMJ

@Matt722 ,

Wondering about air going back in is exactly where my journey with steam started many years ago. I have no quick fix for you nor wish to hijack your thread, but you might be interested in the following/attached for another angle on the whole subject of air.

The hissing sounds of air moving in or out is what costs extra money. Also, all that air is corrosive. The vacuum is a good thing(and also silent).

I assume most here have read the attached literature. But somehow the current wisdom is that intermittent fire renders all this vacuum technology useless. Not according to Hoffman. Today's advice is to process an entire system volume of air in and out on every burn of the boiler? Hmmm.

So why did Hoffman stop making the vents? We lament here often about the number of knuckleheads out there installing boilers wrong and putting rad vents on 2 pipe systems. These folks are going to understand what is going on with vacuum and convince customers to invest in more expensive vents for long term savings? Highly unlikely. So the market just dried up. The site here calls this whole steam heat thing the "Lost Art". Vacuum would be definitely toward the "art" end of things and be among the first things to go.

You can't heat without a boiler. You can heat without vacuum. But even at 1/2 Hoffman's claims of efficiency improvement a major advantage for steam heat has been lost.

Matt722

I originally replaced my vents with Hoffman 1As to adjust each rad but found them unreliable and leaking steam as well as annoying me with the clink noise when the vent closed. I switched to Gorton vents and started out with C and D vents only to replace with 6 and am now looking to replace with 4 and 5. I think I’m still in the return window though. I do like the Gorton a lot but my tenants unit has Hoffman 1As that I may switch to ventrites. Do you know if these clink on close? I read that it’s bexuse they have alcohol floater or something like that.

For my system I plan to add 0-3 gauge, switch Gorton 1 to 2 on the main in question and reduce rad vents from a 6 to 5 to slow down.

I’d love to explore a vacuum system. How easy or cheap is to switch a one pipe gas Burnham IN4 to vacuum system?

nicholas bonham-carter

I think you will be surprised by the real pressure, when you have the low pressure gauge.—NBC

gfrbrookline

I manage a 7 unit building and use ventrite #1, my experience is they don't click if the Ptrol is set to run between 1.5 and .5 or lower and they are adjusted to the the load off the radiator. The problem I had is the tenants kept turning them all the way up to maximize their heat which caused problems in other units. If you have tenants that you trust will not play with them they are great, if not you need fixed vents.

mikeg2015

> @Matt722 said
>
> For my system I plan to add 0-3 gauge, switch Gorton 1 to 2 on the main in question and reduce rad vents from a 6 to 5 to slow down.
>
> I’d love to explore a vacuum system. How easy or cheap is to switch a one pipe gas Burnham IN4 to vacuum system?

To go to vacuum, you need vents that have check valves of some sort. Main vents need to have check valves or be vacuum vents and sometimes you need a vacuum pump.

Biggest challenge is leaks. Many of your radiator valves will need to be repacked and rebuilt.

PMJ

Pehaps rhe biggest surprise for me was how little time I spent on leaks. 90 year old piping, tightened some valve packings - no replacing or rebuilding anything.

This is not an all or nothing deal. Everything leaks - the question is only how much. More vacuum is better. A little vacuum is a lot better than none.

Matt722

> To go to vacuum, you need vents that have check valves of some sort. Main vents need to have check valves or be vacuum vents and sometimes you need a vacuum pump.
>
> Biggest challenge is leaks. Many of your radiator valves will need to be repacked and rebuilt.
>
>

Thanks. Would you mind sharing which vents you use for your mains and rads that have check valves. Are the rads using all the same vents or are they sized like in a non vacuum system?

Matt722

> @nicholas bonham-carter said:
> I think you will be surprised by the real pressure, when you have the low pressure gauge.—NBC


So instead of fiddling with a mercury ptrol and adding a 0-3 gauge, is there a new ptrol that I can switch to which more accurately controls and reads pressure? Is that a vaporstat? If so is there a specific brand or kind to use and is install just merely swapping them out or any tips for switching? Thanks guys. This is usueful stuff here.

Gsmith

Why not do as NBC suggested, as a first step, put on a 0-3 psi guage and see what the actual pressure your system generates. You may well be surprised and not need to change the ptrol or to a vaporstat.

coelcanth

Matt722 said:

Thanks. Would you mind sharing which vents you use for your mains and rads that have check valves. Are the rads using all the same vents or are they sized like in a non vacuum system?

i might be wrong, but I believe that there are no production vents currently available to run a one-pipe steam system on vacuum.

Matt722

> @Gary Smith said:
> Why not do as NBC suggested, as a first step, put on a 0-3 psi guage and see what the actual pressure your system generates. You may well be surprised and not need to change the ptrol or to a vaporstat.

Yes Gary I’ll prob do that. Just figured I get all the info I can on my options before doing anything. The more I can do in a round of tinkering the more I can free up my time for the little one.

Fred

The Vaporstat you want, if you go that route is the Honeywell #L408J-1009. Do as Gary says and determine if you need to add a Vaporstat. Also, Code requires that you have a Pressuretrol on your boiler so you will want to add the vaporstat, wired in series with your Pressuretrol and other safeties.

Keep in mind that PMJ has a two pipe system. It may be more of a challenge to get/keep a vacuum on a one pipe system.

PMJ

@Fred is correct, I have a 2 pipe system which is easier.

I just take the opportunity when I hear the air issues to make another plug for someone trying one-pipe vacuum somehow. One of these days someone is going to get it going again and reap all the lost benefits of long ago. I don't believe the vacuum will interfere with balancing in one pipe as all air removal/balancing occurs only when the system is above atmospheric pressure anyway... the only condition under which air can possibly leave the system. Since some air will always leak back in during the vacuum state, that air must be removed each and every burn of the boiler. As it leaves, only after the system has again returned to just above atmospheric pressure on the next burn, it will be controlled through vents just like an open vented system.

While I assume most have seen it, here is a link to @Gordo 's video of a demonstration unit for the Hoffman vacuum vent. Picture your boiler continuing to make steam after the burner goes off every cycle as the vacuum sets in. Picture also that steam continues the positive flow from the boiler and into the rads in the vacuum. Cycle after cycle this does in fact add up to something just as Hoffman says. This is what I enjoy with my 2 pipe, and I do agree with the Hoffman deadmen, it wins the race against open vented several ways.

https://www.youtube.com/watch?v=4ple0cVv6ow

nicholas bonham-carter

What a wonderful video-thanks so much!!!!!
Since we are worshippers at an temple of ancient art, and science, it is important to keep, and study these old relics to better understand how to move forward into the future with our old systems, which can be made to function well, if we follow certain rules.—NBC