Noisy Heat Timer Vari-valve

matt1912

Hello everyone. I live in a home built in 1912 with one pipe steam heat coming from a New Yorker Boiler model number: CGS40C. I have approx 60ft of 2in main supplying 6 radiators (four downstairs and two upstairs. The mains are vented with a Barnes and Jones Big Mouth as well as a Gorton #2. After a few modifications to my system last season, (main vents, insulation, radiator pitch, and pressuretrol adjustment) I am overall pleased with how well it is running and heating the house. Last season I installed Varivalve heat timers to all radiators. Since then, the valves have been very noisy. For the entirety of the boiler firing cycle, the varivalves are expelling air and making lots of noise. This may sound strange but it almost sounds like they are “breathing”. Is this a product of failed valves? Is it normal to have this much air vented at the radiator? Ive read that varivalves may be overkill for residential systems. I have the valves adjusted to almost fully closed on all but the last radiator down the line. If you guys have any thoughts or suggestions on how to decrease the noise, let me know. Any input would be appreciated as this noise is keeping me up at night! Thanks! 

KC_Jones

Those vents are very aggressive and we see complaints about them fairly regular around here.  On 50% setting it vents as fast as a Gorton #1 main vent.  When full closed they vent almost as fast as a #5 Gorton rad vent.

The aggressive nature could be allowing the steam to favor the radiators instead of venting the main first.  Could be contributing to just slowing the steam to move “too fast” into the rads.  It’s usually better to start with aggressive Main venting like you have, then vent the radiators slowly.  After that you can increase venting on individual radiators as needed to get balance.  The heatimers just can’t really go low enough and their aggressive nature will make it difficult to tune.

If you need adjustable, Maid o Mist has a replaceable orifice vent system, or ventrite has an adjustable vent that is better.  Hoffman also has one, but some people (including me) think they can be challenging to properly adjust.

matt1912

Thanks for the info. I’m not sold on needing adjustable radiator venting and will more than likely move to a slower non adjustable radiator vent if I continue to have problems.

For the time being, I adjusted all my radiator vents to fully closed with the exception of the last two down the line, which are open about a quarter of the way. I left these open slightly because these two radiators are always last to heat up and I worry that fully closing the vent would prevent them from warming. As a result, they are the only two vents making noise. They still appear to be venting a large volume of air. I have confirmed that my main vents are open, as they are also venting air.  

My concern is either that my main venting is inadequate and my radiator vents are doing all the work OR something much more strange is going on and the varivalves are somehow letting air into the radiator (I know this sounds crazy but it honestly sounds like the vent is both “exhaling” and “inhaling”). 

I will leave everything as is until temperatures drop and I am out of “shoulder” season. Maybe this is all just a result of the boiler firing so infrequently and cold main piping between cycles. Current daytime temps in Michigan have been warm and the boiler is only cycling at night. 

I will keep you posted, thanks!

mattmia2

If 2 of the radiators are taking significantly longer to heat and there isn't a huge difference in the distance of pipe between them and the next radiator that heats quickly, look for a sag in the piping or other issue with the piping that is trapping water. If there is a pool of water in the pipe the steam will have to heat and evaporate that before it will progress further along the main. That evaporating of the water could be the source of the "panting".

SteamingatMohawk

You said, "The mains are vented with a Barnes and Jones Big Mouth as well as a Gorton #2." but you did not identify where in the system these vents are located, such as, just after the last riser to a radiator, or at the end of the return to the boiler (before the Hartford Loop).

Also, does the 60 ft number include just the length to the last riser or the full length of pipe to all risers and back to the boiler?

Long Beach Ed

We installed hundreds of those vents when they first entered the market. About 25% of them failed in a year and Heat-timer wouldn't even acknowledge our letters. They have a design flaw that causes some of them to fail closed when the bellows detaches and drops into the seat. If you shake one and it rattles, it failed in this manner.

Radiator venting is not as simple as bigger is better. One problem is that a big vent can create a bodacious amount of condensate very quickly in a radiator. The fast venting can negate the return of this condensate and cause a very messy clash between steam and condensate in the radiator run-outs. This often causes the "panting" you describe as waves of water slosh through the mains, cooling steam and creating more condensate without properly heating the radiator.

Before you install nostril-sized vents you must also confirm the quality of your steam. Wet steam will cause problems with fast venting. Poor near-boiler piping, low headers, undersized runouts or risers, improper pitch or sags or a poorly designed boiler can cause very wet steam to enter the mains when vented too quickly. The exiting velocity from the boiler is just too fast, and it pulls water into the mains.

If your steam is dry, and the vent is not closing but venting steam, it is defective. If your steam is wet and the vent continues blowing wet steam throughout the firing cycle, it is possible that your vent is too large for your particular system's configuration.

matt1912

Thanks again for the input everyone. I’m not sure how to get a good idea of the quality of my steam, I’ll add that to my reading list. However, I do know that my near boiler piping is correct. The main vents are both located at the end of the return just before the Hartford loop. I will have to take a level downstairs and check for sag in my mains. 

Long Beach Ed

On most modern boilers, the bottom of the steam header should be no less than 24" from the water line. If it's less, the steam quality tends to suffer. Another detriment to dry steam is radiator vertical takeoffs and header takeoffs from the top of the main. They tend to rain condensate into the steam. There are exceptions, but a 45 degree takeoff is better.

If these things check out, the pressure's low, the radiators and pipes are properly pitched, and the boiler piping is correct then your steam quality should be okay.

If you can see the steam blowing out of a vent, then the steam quality is wet and the vent is bad.

matt1912

Thanks Ed. My headers and takeoffs from the main appear to be vertical as opposed to 45 degrees. I don’t appreciate any sag in the mains throughout the basement. There is one area where the main travels under a slab and I cannot check it for pitch. I also don’t see any steam or water coming out of the radiator vents. It’s just cold air. 

I guess my main question here is should the radiator vent be venting air throughout the entire steam cycle? I understand that the vents are designed to close when they get hot. However, my radiators are all a bit oversized and don’t ever get hot all the way across. My largest radiator, which is the first off the main, only ever heard about a quarter of the way. Will the vent only close if the radiator heats all the way across to the vent? 

Thanks 

Gordo

https://youtu.be/-S63pXuF_Mk

matt1912

UPDATE:

I noticed my sight glass was completely full. So full that I couldn’t see the water line at the top. I drained it down to about 2/3 full. The last two heating cycles have been dead silent (no more panting vents or banging noise in the main) with nice warm radiators all through the house. Not sure if this was causing all those issues but I’m going to leave it alone. Maybe too much water in the radiator leading to wet steam? Not sure. Thank you all for your input!