Main Vent valve replacement, cold side very cold

bluefull

Hi folks, I am hoping someone can give some advice. I've got a three story building, attached with railroad like apartments. We've got steam heat and it looks to be a one pipe system. About 5-10 years ago we had a new oil boiler put it.



The problem is that the radiators on the side of the building near the boiler and the middle rooms heat up ok. The far side though, the bedroom radiators seem to be cold. Have to put the heat up way high to get them to give off heat in all three floors.



I wish I had found this site sooner as the hardware guy and even the boiler folks were not able to give sound advice. I see now that venting might be the issue.



The picture below is the main vent on the cold side of the building which leads up to the bedrooms. Looks to be 3/4" and the picture doesn't show it but the hole is on the other side and not painted over.



The other problem is that the basement is semi-finished so this is the only main vent that is visible. My question, should I start by replace the cold side with a single Gorton 3/4" and see if that helps? Should I rip up the ceiling looking for the main vent

near the boiler? The boiler side radiators work fin on all three floors.

bluefull

Boiler pipe pictures

Here are some pictures of the boiler room (sort of left to right) which are not very good now that I look at them. I can take better pictures if it might help. I'm guessing the other vent, the shorter main is somewhere just outside the boiler room? Assuming I should rip up the ceiling on that side?

nicholas bonham-carter

more main venting needed

that main vent is due for replacement. i don't how long your mains are, but i would suggest a gorton #2, as it is the most capacious, and you can never have too much venting.you may need more main venting, but this is the place to start.--nbc

bluefull

Gorton 1 vs 2 and thread size

Nicholas, thanks for replying. I see Pexsupply has a Gorton No. 2 Straight Air Eliminator for $63 with a thread size of 1/2".



There is also a Gorton No. 1, 3/4" x 1/2" Air Eliminator (Main Vent Valve) for $21. It shows two thread sizes, 1/2" & 3/4".



So the Gorton No.2 would do better considering a single replacement (not an antler setup)? Would I need an adapter? I hope it fits height-wise.

BobC

Bob

The Gorton #2 is maybe 6-1/2 or 7" tall and you will need an adaptor because it only comes with a 1/2' thread. The #2 has more than 3X the venting capacity of a #1 and costs just about 3X as much



If height is an issue go with an antler arrangement, just make sure it slopes towards the main so water will find it's way out.



Bob

bluefull

Adapters

Thank you Bob and Nicholas. I will be ordering that Gorton #2. As for the adapter, I can't seem to find a 1/2" to 3/4" (the current valve looks to be 3/4", I've had a heck of a time trying to get it off so far) on Pexsupply.com, will any of the big box stores have them? Anything specific to look out for?



Have to say thanks again, I really wish I had found this site sooner. Spent about $70 on radiator valves (stepped sizing based on distance from the boiler and floor to floor) on the advice of the hardware store but that didn't do much of anything. Now I see that in terms of radiator valves, it may better to just fit them according to the size of the radiator.

Rod

Venting

Hi- Wow ! Your main vent looks like it is old enough to vote! They can sometimes  be cleaned out by soaking in CLR or by boiling in white vinegar. Even if cleaning it restored it to a new like condition, your main is still way under vented.  You need to add more venting capacity.

There’s an old steam adage: “Vent your mains quickly and your radiators slowly!”



 I think what may be happening is that since your main vent capacity is small, the radiators are filling with steam sequentially meaning that as it travels down the steam main away from the boiler the steam fills the first radiator it comes to and then the second and so on. As the thermostat is usually in one of the rooms which has a radiator(s) close to the boiler end of the steam main, this rooms heats up and the thermostat is satisfied and shuts off the burner  sometimes even before steam enters the radiators on the far end of the steam main. (When you set the thermostat much  higher than normal the burner stays on for a longer period of time which gives the steam time to get to the radiators at the far end of the main.)



The solution to this is to fill the mains with steam all the way to the end first so that steam reaches all the radiator at about the same time. This is accomplished by allowing the air to escape from the steam main as quickly as possible through the use of large capacity venting.

Take a look at this link which leads to Gerry Gill’s Website. Gerry Gill is a Cleveland steam pro and is an expert on venting. In fact he wrote the book on venting which you can buy in the Shop section of the Heating Help website.    http://www.gwgillplumbingandheating.com/webapp/GetPage?pid=415

Be sure to take a look around Gerry’s website as it is loaded with great info about steam heating.



Gorton Main Vents-   As has been mentioned the Gorton #2 has 3to 4 times the venting capacity of the Gorton #1.  The Gorton #2 has ½ inch male thread and the Gorton #1 has 3/4 male thread on the outside and ½ female thread on the inside so you can easily attach it either way. As NBC suggested you might start with a Gorton #2 or if overhead clearance is a problem use 3ea.Gorton #1 (s) which is the equivalent of a Gorton #2 . Use an antler to attach them. I’ve attached a drawing of a low profile antler below) The advantage of using an antler is you can always add an additional vent by adding another vent and a tee.  While you don’t have to use a pipe union with the antler, the union makes it much easier to take on and off for maintenance or adding another vent. Having large capacity main vents saves fuel as the faster the steam gets to the radiators, the faster the building warms up and the faster the thermostat setting is satisfied and shuts the burner off.  Less burn time means less fuel used.

 

Radiator Vents-  Quite often in these situations large capacity radiators vents have been added to try to fix the “no heat” situation.  Let us know what the make and model number of the present radiator vents and we can tell you the venting capacity.  If they are of high capacity, they  will probably need to be removed and a smaller capacity vent substituted to help better distribute the steam evenly to the radiators.  Surprisingly enough the smaller capacity radiator vents quite often cause the radiator to heat up faster. 



Saw you recent post - You need a 3/4 x 1/2 Reducer Bushing to attach the 1/2 inch MPT #2 to the 3/4 FPTvent hole. These should be available at Home Depot or your local hardware store. On steam systems use black iron fittings. Don't use galvanized pipe or fittings as he zinc coating flakes off and will plug the small vent holes. 

- Rod

bluefull

G2 too big

Thanks Rod for the additional info and the reducer help.



Just an update, I purchased a G1 and a G2. I replaced the old vent with a G1 for now. Not much difference.



The Gorton No.2 is just too big for the space and I'll be returning it. So I am looking to do an antler system using four Gorton No.1s as Rod described.



I asked the gentlemen who came to look at the boiler recently about the main vents. He felt there was only that one vent on the system (the one being replaced in the picture). As the hot side, boiler went straight to the radiator upstairs. Does this sound correct? The distance from the boiler to the cold side is about 70ft.



If I do an antler system, can I find all the parts at a big box store like home depot or should I order from Pex since I have to order 3 more G1s anyway.

BobC

A lot of #1's

If that 70 ft main were 2-1/2" pipe it would contain 2.4 cu ft of air and the Gorton #1 will vent at 0.33cfm so you may need a bunch of them - maybe six or more (make sure the antler slopes back towards the main.



Make sure the main has consistent slope, if there are any sags in the main it will be a problem.



Bob

Steve_175

Should be a vent on each run

Unless you have a counter flow set up you should see a vent on the end of each return. Not at the farthest radiator.

bluefull

Ceiling Drywalled

Bob, the basement ceiling is drywalled so I only see the end (in the picture) which had the old vent on it. I'm hoping not to have to rip up 60+ feet of drywall. To make the antler setup, would all the parts be available at big box store?



Steve, any idea where the vent near the boiler might be?



Right now I put the thermostat real high to get heat in to the cold side bedrooms on all three floors. Not a good solution, wasteful, plus it gets too hot in the other rooms, and the bedrooms don't stay nearly as warm. Dry sinus issues are made even worse.

BobC

experiment

You should be able to get what you need to build an antler at a big box store, but sometimes the selection is a bit sparse. Sketch out what you think it will take and bring a list with you.



That ceiling makes inspecting a bear. Do you know how long it takes for steam to make it from the boiler to the current main vent?



Here's an experiment to try, time how long it takes with the vent you have now and then remove the vent and see how long it takes then. Be ready to switch the boiler off as soon as steam comes out of the open tapping. Make sure conditions are the same, the boiler should be dormant for the same amount on time for each test for the results to be valid.



Bob

nicholas bonham-carter

Venting solution?

Have a look at this thread. The use of a trap might solve your headroom problems, and is better sized to your pipes sizes.

If this is a parallel flow system, then the main vents should be on top of the dry returns where they drop down to wet returns. Trace the wet returns to find where the drop is, and the vents should be there. Check your pressure if you have sinus problems, as the radiator temperature increases with pressure. Keep lower than 1.5 psi.

You may need a pro for this:--NBC







http://www.heatinghelp.com/forum-thread/144854/Crossover-trap

Paul48

re: headroom

What ever that material is, over that existing main vent needs to be removed for more room for vents. It can be boxed in for appearance, in the spring.

BobC

radiator vents?

If this is a single pipe steam system what kind of vents are on the radiators? We know we should vent the mains fast and the radiators slowly so perhaps some judicial juggling of the radiator vents would help.



Bob