too much venting

William Faust

I am thinking about using them to vent my steam risers. You said that you would not recommend using them to vent steam mains which are sort of the same thing.

Allan_4

too much venting

Is it possible to overvent a steam radiator and what are the effects of overventing

Long Beach Ed

For one...

With a cold radiator that is vented tooo fast, steam will condense very quickly, makeing massive amounts of condensate. Because of the fast venting, the volocity of steam in the riser to the radiator may impede the flow of returning condensate.

The result can be gurgling noises, or accummulation of condensate and spitting vents.
In an extreme case, where radiators are very cold, as in a church that is heated only for a service, all hell can break loose with water spitting everywhere.

You can also slow the flow of steam to other less well vented risers, mains or radiators, disrupting balance.

On some well-designed systems, depending on the flow of steam from the boiler, you'll have no ill effects with huge vents.

I vent the best I can and then solve problems that arise.

I'm sure others have lots to add to this also.

Long Beach Ed

Long Beach Ed

For one...

With a cold radiator that is vented tooo fast, steam will condense very quickly, makeing massive amounts of condensate. Because of the fast venting, the volocity of steam in the riser to the radiator may impede the flow of returning condensate.

The result can be gurgling noises, or accummulation of condensate and spitting vents.
In an extreme case, where radiators are very cold, as in a church that is heated only for a service, all hell can break loose with water spitting everywhere.

You can also slow the flow of steam to other less well vented risers, mains or radiators, disrupting balance.

On some well-designed systems, depending on the flow of steam from the boiler, you'll have no ill effects with huge vents.

I vent the best I can and then solve problems that arise.

I'm sure others have lots to add to this also.

Long Beach Ed

Allan_4

Any specific valves to stay away from? I heard Varivalve by heat timer are not that great.

gerry gill

i think gorton vents

are the best..i've had overventing issues with the varivents..never had it happen with the gortons.

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Howard_4

i went thru 3 varivents myself. What makes those so different from Gorton? Not worth it , theyre expensive and dont last.

Daniel_3

Varivalves

So what was the problem with the varivalves? I have them all on my rads and have nothing but good things to say about them. They make no noise and they vent fast because the rads get hot much faster in comparison to the doles and hoffmans that were on them ( they were old anyway). I wouldn't use them as main vents as Heat-Timer encourages but as vents on rads I think they're great. After a few more years I'll have to see but they're contruction seems to be far better than others on the market. Unless the poppet and seal go or the adjustable bronze collet gets fouled up then I don't see why they would cause problems. If they seem to vent too fast why not just keep the vent more in the closed position?

Howard_4

Im curious of what the experts think of them

Long Beach Ed

VariValves

VariValves by Heat Timer are kind of neat, but have a major manufacturing flaw. The syphon bellows in them is mounted from the top of the valve housing, pressed into a brass machining. When they expand too much, they deform and pop out and forever seal against the seat.

Of about 500 we installed in one ill season, perhaps 120 failed the second winter and another 100 failed since then.

We opened several of them, photographed the falts and sent them to Heat Timer.

They ignored us.

We wrote several times and called -- even wrote to the president to no avail.

This could be a nice product, but it's not.

Since then we've used Gortons, with virtually never a problem.

Long Beach Ed

Daniel_3

Well that stinks considering I spent quite a bit of money on about 13 of em . . . . =(

Howard_4

Nice explanation, thnx Ed
I have Hoffmans on all my radiators, which are fine but i plan on changing them all to Gortons by next fall.

Daniel_3

So if one fails (which none have yet) I would expect a vacuum to form or air pocket which would forever keep that rad cold?

Long Beach Ed

If one fails...

The radiator would not heat if it fails closed, which is how the VAriValves tend to fail.

Hey, lots of them are still working, six years later. But the failure rate was high. Simply a bug in the design.

Fred Harwood_2

Over Venting

> Is it possible to overvent a steam radiator and

> what are the effects of overventing



Over venting a rad sometimes will allow steam to rush through the lower radiator manifold rather than the upper manifold, shutting the vent before much air can leave the rad. If you need lots of venting to bring steam to the rad, try to vent the riser more than the rad. Try to let steam into the rad no faster than it can rise up the rad columns and displace air ahead of it.

Daniel_3

True, this is called "short-circuiting" . . .

Ken_40

Unless I'm blind...

Not one poster mentioned the impact of excessive steam pressure on vents.

NEVER run a "standard" steam system with more than 2# of boiler gage pressure. On a "vapor" system, never run over half a pound (8 oz.)

Having said that, we have used both Vari-Vent's and Gorton's and find most rads over-vented and the mains under-vented - by a bunch!

Over-venting rads creates spitting, and as already written about, surging steam and reverse flow condensate "crashing" banking and making noise that is completely avoidable.

William Faust

Vari-vent

This term refers to Heat-Timer's Varivalve?

Ken_40

Oh (;-o)

Is that what they call 'em now (;-o)

William Faust

Yo, Ed

Question for you. I had been considering using Heat-Timer valves to vent my supply risers, but the criticism from you and Gerry Gill unnerved me. I'm wondering what operating pressures were used that resulted in the unacceptably high (and early) failure rate. I will normally be operating at 10 oz. or less - do you think that has a bearing on whether I might suffer the same fate?

William Faust

Heat-Timer vari-vents

Were you using them on radiators, mains or supply risers? How quickly did they fail? Was this recently? What was your cut-out pressure?