main vent placement on a counterflow

JHprovidence

Does anyone have pics of placement of main vents on a counterflow system. I am trying to get a place i rent more efficient! There are no main vents here! This is how my main line ends

Rod

Location of Main Vent -Counterflow Main

Hi- On a Counterflow main just place the Main Vent close to the end of the main farthest from the boiler.  Ideally it should be after the last radiator take off but since the last radiator takeoff is at the end of the main you can place the vent as shown in the picture.

Drill and tap a proper sized vent hole in the top of the main.

- Rod

nicholas bonham-carter

Enlightened tenant!!

You could be a treasure for your landlord, with all the time you have put in on this system!!!!!!

The main vent on a counter flow should be at the end after the last rad, if possible. Often the pipe is jammed up against the basement wall, making it different to do anything. In such case, you could put the fastest radiator vent on that last radiator, with SLOW radiator vents on the intermediate ones.--NBC

JHprovidence

tee joint

If we added in a tee joint here how far should we go before main vent placement? There is about 10 fee before the wall.

MDNLansing

Check the El

That elbow might have a plug in it on the outside of the joint. All of the corners of my mains were piped with elbows that were plugged. I don't know how common that is, but it's worth checking before tapping. Feel around the "insulation" on the outside corner of that fitting and see if you feel the top of a plug sticking out. If you think you might feel one, it would be worth removing some of that "insulation" to confirm.

Rod

Installing a Main Vent

Hi-  Adding a tee is a lot of work that really wouldn't gain you much. Just tap a hole in the top of the main and attach your vent there.   It's done all the time. It only has to take a 2 PSI pressure and if you don't feel it is strong enough you can reinforce the pipe attached to the main using a fillet of JB Weld.

- Rod

JHprovidence

tapping

Okay so if my landlord did this and we used a hoffman 75 would we drill and tap the hole and then use a nipple to attach the vent or just put the vent right in the pipe (it is in a boiler room and don't want to run the risk of being to hot for a gorton 2). Also since there is plenty of room could we tap right into the elbow so if we needed more venting later it would be easy to add?

Ironman

Stay Away From the Ell

You should stay at least 15 inches from the Ell. If a water hammer occurs, the steam will pick the water up and slam it into the ell with tremendous force. If the vent is there, it will be damaged or destroyed the first time it happens.

JHprovidence

what would you suggest?

With there being plenty of room on the back side what would you suggest I do?

nicholas bonham-carter

No main vents in Providence

You could try a Gorton D on the radiator on the end of the main, and riser, and see what improvement results. All the other radiator vents should be slow Hoffman 40's for best results.

Once again, what a treasure you are to help your landlord, instead of finding yourself in a constant confrontation, complaining without any resolution!--NBC

JHprovidence

two less radiators

The original design had 7 instead of 5. This includes 2 pipes that are now blocked off… so 29% percent of venting locations have been removed. I put a C on the last radiator but it is in a bedroom. This makes even more noise at the start of the cycle than the 6 that is on there now. Also even at the speed of the gorton 6 steam gets ahead of air a lot of the time. During the cycle the vent will sputter and gurgle after being shut as other radiators fill up. The extra steam is coming down the line pushing all of that extra air out. If i slow down the rads closest to the boiler the same thing happens. AIr coming out with steam. When all the air is gone that stops. It stays shut… but that can take 5 to 6 min. I can speed up the living room. That fixes the problem, but then the bedrooms are cold. I can slow things down to even more but then cycle takes an hour… not an option. This is an improvement over vent rite that was there that would blow out a lot of air and then slam hard shut, but I need to figure out a solution of where all of that extra air can go. Pressuretrol is set to 1 psi because any more really cooks the place. I am open to any suggestions.

Dave in QCA

an Easy Option

Now, we all know who bad that Heat Timer Varivalve radiator vents are because of the fact that they vent WAY to fast... So fast that they make decent main vents! In fact, in the wide open position that vent at .660 cfm at 1 oz pressure, compared to Hoffman 75 main vent that vents at .50 cfm.



So, one option would be to drill and tap a hole in the top of the pipe where Rod has indicated for 1/8" pipe thread. Then simply install a straight patter varivalve. Put it in the wide open position. Since your system is counter flow, I don't think you have to worry much about condensate coming down the pipe; it is all going the other direction and the only condensate load here would be from one radiator.



And, while we don't talk price here, in general terms, the price is very low. Pexsupply is a good source.

http://www.pexsupply.com/Varivalve-VASA-Varivalve-Adjustable-Straight-Valve-3841000-p

JHprovidence

thank you dave

I was wondering if those could be used for that purpose. So we would drill in and put the vent right on the pipe? Also about how many inches should we be back from the elbow? He has a problem sort of like this on on of his run outs so if it works for me it will work for him too!

Dave in QCA

My Pick

I think i would pick a spot midway between the elbow and the pipe hanger. It should make it easier at the location.



I used the same technique in adding venting to risers and very long run outs on my system, which is actually a two pipe system. In the end, I ended up solving all of my balancing problems by using inlet orifices. Then, later when restoring the system to its original vapor/vacuum operation, I removed all of the riser vents that I had added because in my case they were no longer needed. So, I know first hand that it is a very easy process to add these to a main, and they will vent quite well.

JHprovidence

that should help both of us

Just cause since I have not done this before. I know that the treading tool tapers larger as it goes in. What size drill bit should be used to not make the hole too large?

Dave in QCA

pipe tap

Buy and 1/8" pipe tap. It will tell you what size of drill bit to use. When you use the tap, the beginning is the toughest because you need to make sure that you hold it true and don't wobble it as you turn it in. Once it has started as is cutting threads, about every half turn, back it up a little bit to know of the thread cuttings, then proceed forward a half turn, etc.

JHprovidence

side drill

I don't have a side drill and I am not sure if he has one either. Any recommendation of how much power we will need if we have to rent or borrow one?

Dave in QCA

Nothing special

I just used a standard 1/4" electric drill. You need to have a good sharp bit, but no special power for the drill.

JHprovidence

sounds good

now I just need to have a talk!

mcsteamy

Dave,

There might be an even easier option worth taking a shot at---Some radiators will have a plugged vent tapping on the side near the valve.  I would take a look for that first, and see if the plug will come out with a really big screwdriver.  That should work just about as well as drilling it into the run-out.  The vent will snap shut almost as soon as steam hits that radiator.