Heat Timer-Vari valve

nicholas bonham-carter

in my experience, the sound of hissing vents has sometimes meant too high pressure.check your pressure before you expose the new vents to a lethal dose, which can make them into paperweights!--nbc

Kool Rod

Heat Timer-Vari valve

Hi All.
I will be placing hissing radiator vents with the vari valve. my question is, my living room radiator is about 46" long, would this unit be efficient to vent a cast iron radiator that big? the opening seems so small or is this stuff usually pretty standard?

Thanks, and sorry for the dumb question..

Kool Rod

pressure is set to cut out at 1.5psi and back in at .5psi which is what everyone recommends on this forum. should i drop the cut out at 1 psi?
frankly at 1.5psi the boiler cycles a quite a few times before reaching desire temp...

Thanks again

Ross_7

Main vent(s) sized big enough?

Check your vents on the main also. They may not be big enough for the amount & size of the piping installed for the mains.
Ross

David Nadle

How many vents are hissing?

If you have loud vents while the radiators are still cold, you likely don't have enough venting on the mains.

If while the radiators are hot you have just one vent hissing, replacing it should work. But if it's many, you may have problems with wet steam unrelated to the radiator vents.

The Varivents run on the fast side, with a wide adjustable range. Should be fine for your radiator.

Brad White_203

I agree

with the points made regarding main vents and that Heat Timer Vari-Valves have good range, higher than some Gorton air valves.

Do check the main vents and make sure that your radiator vents are not working too hard.

I tend to find Vari-Valves spit if you have wet steam more than other valves in the same conditions (the small size I suspect makes them less forgiving).

Kool Rod

oh gosh, how do i fix wet steam?

Brad White_203

A towel?

Do you have wet steam, Brian? Meaning, does your sight glass have rivulets down the insides? Do you hear sloshing especially during start-up?

Most wet steam starts at the boiler. Using too small or not all of the available exit tappings accelerates steam exit velocities and can draw up water from the boiling surface. Having the system take-off between two boiler risers is another way to make wet steam.

Using all of the tappings and enlarging them helps a lot. Extending these to a dropped header is another. Having the equalizer properly sized and located after the system take-off (not expecting a side take-off returning to the boiler to do the right thing), is another way to make dry steam and keep steam dry. Oh, insulate those pipes too.

Kool Rod

my sight glass has water dripping along the sight glass walls from the top down.
at cycle, the water drops below half and at cold the water goes back up to half way up the sight tube.


vents does nothing but hiss, no water leakeage though.
knowing this, do i have wet steam?

Brad White_203

Hard to tell

without looking at it in operation, but you may hear some sloshing on start-up. If you go get an oven mitt and remove an air vent from a radiator nearest your boiler, if you get a long plume of steam without spitting, that says "dry steam" to me, but is not an absolute. If you find you have vents giving up the ghost routinely, that is an indicator. Subjective unless you have glass piping.

Use your ears first though and always common sense.

Do you have photos of your near-boiler piping?

Kool Rod

brad "vents giving up the ghost routinely"
what do you mean by this?

Thanks

David Nadle

I think Brad means

that new vents won't fix wet steam, they'll just get ruined and wont close like the old vents did. Rinse and repeat.

Your boiler water may be oily or dirty, causing the waterline to jump up and down a lot and the water running down the sightglass you mentioned. Skimming and cleaning the boiler could solve the problem.

Alternatively, your boiler could be piped badly. That's why you should post a picture.