Wika 3 psi gauge

ChrisJ

I've been having some minor difficulties with my 3 psi gauge in the sense that I seem to develop a slight vacuum due to the pigtail.

I decided to shut the valve to the gauge off just to keep the needle from being pulled way back at times.  It seemed no matter how much I compensate for it, it would still get pulled back some.

<strong>Are there mini-vacuum breakers that would work with this?</strong>



Also, with the valve closed last night the gauge it was dead on zero.  This morning after a very long run it ended up indicating an ounce or two of pressure.  I'm guessing this is merely due to temperature change in the room or perhaps barometric pressure change?  I doubt that 1/4" ball valve leaked any pressure to the gauge.

Abracadabra

vacuum

When do you see the vacuum? After a cycle and the boiler cools down? That sounds normal.  Especially if your vents aren't opening up after the cycle. I've seen some vacuum breaks posted on here. Don't recall where though, sorry. 







When you shut the valve, was the boiler & pigtail hot?  If so, that will give you some vacuum when everything cools down.

ChrisJ

vacuum

Yea, I see the vacuum after the boiler shuts down.  I had closed the ballvalve to the gauge while the system was running to keep a slight amount of pressure in it assuming it would cool later on. 



I also noticed when I opened my skim port a while back I heard it suck a little air in.  Why would the boiler have a slight vacuum, shouldn't all of the rad vents and main vents prevented this?  All vents are Hoffman 1As and are 2 months old.  Main vents are Gorton 1s and are also 2 months old.



This shows how the gauge is installed,  valve was open when I took the picture during a very long run cycle.





Maybe a dumb question, but is the vacuum harmful to the gauge, and if not should I zero the gauge with it removed from the pigtail and then just ignore it being pulled into the negative?

Abracadabra

vacuum

When steam condenses it creates a vacuum.  It's part of what makes a 1-pipe system run.  After all your pipes and radiators are hot, all vents shut.  When the boiler ends it's cycle, steam starts condensing.  Remember, vents are all shut because they are shut and they don't reopen until they cool off.  Depending on the brand they make need to cool off to 130 or 140 to drop out.  Gorton G2s are notorious for this. Steam condenses at a temp under 212. Steam condensing, no air entering your pipes of radiators means a vacuum has to occur.  I see a vacuum at the end of a cycle as well.  I don't think it will harm the gauge as long as it's not excessive.

The gauge should show 0 when boiler is cold and that ball valve you have is open.  I'd like to have a little more height for the gauges off the pigtail than you have there.

haaljo

Seeing a vacumn is fun

I keep my 3 lb wiki off the zero by 4 oz. so I can see the vacumn on those rare occurences. This link to a pdf booklet most excellent:

http://www.heatinghelp.com/article/163/Older-Steam-Heating-Systems/1310/How-to-Lock-Out-Air-The-Heat-Thief

Was talking with a tech from Russia and the wonders of their one-pipe vacumn systems. Being a layman, over my head (and also he was only a few years since leaving Russia so hard to understand). But he said something going on with a check valve; some kind of timed operation and maintaining a vacumn for 30 min? Really smart guy.

I did some research (including the above 1929 hoffman booklet/advertisement).

Great stuff!

Abracadabra

wow...

I just read that book.  Why aren't more vents like that?

ChrisJ

vacuum

Yea, why can't we find these vents anymore??



Or can we?





I'm going to assume the only downside is you need a really tight system that is pitched correctly otherwise it should work?



I'd gladly put the work into my system if I could find those vents and get them to work.

haaljo

The russian engineer was talking about a check valve

on each radiator and minor piping change so don't think you can do it willy nilly.

There have been posts on vacumn systems by techs that keep them working. Reincarnations of Dead-Heads.

Mark_125

Are those guages adjustable?

Haaljo, would you please explain what you mean by this: 'I keep my 3 lb wiki off the zero by 4 oz.' Do you adjust the guage to do this. Whenever my system is idle, the 3lb guage is about 4oz below 0 - its always like this, I too am concerned about damaging the guage. Sometimes at the end of the cycle it drops to -8oz.

haaljo

Mark, pry off the plastic front shield and turn the little ...

screw under "psi." Set mine at idle at 4 oz.

If I force the system to go to 2 lb., Can see negative pressure; couple of ounces; after boiler shuts down. Only lasts for a few seconds.

Normally, she runs for an hour at 12 oz. before pressure goes to a pound. Rarely happens.

Weekend it's supposed to go to zero. I'll be watching to see if pressure gets up to 2lb (not good) and at shut-off if she goes negative (lot of fun).