Solution for water spitting from air valve (convector radiator)

erics_guerron123

Hello all,

I have a steam boiler system and I have this convector radiator at the end of my steam pipe line on the first floor. I am having this issue where, when the steam boiler turns on, and a couple of minutes later, this convector radiator starts spitting water through the air valve at the right end. I hear water being pushed to the air valve and then water starts spitting.

2 plumbers have told me that they will have to cut the basement ceiling underneath this radiator and see if there is a blockage in the return pipe to the boiler.

A 3rd plumber suggested making the following modifications to the service valve (see post it note image). According to this plumber, the issue is with the brown coupling between the service valve and convector pipe that is holding water and preventing water from draining back to the service pipe. As a result when the steam comes in, it forces the water to spit out of the air valve.

My question is, would making the modifications from the third plumber fix my issue? Thank you all.

Big Ed_4

Normal problem with baseboard on steam system. It should be installed two pipe , but for now you want a slow vent and insulated mains …

erics_guerron123

https://forum.heatinghelp.com/discussion/comment/1887812#Comment_1887812

I turned off the service valve to stop the water spitting. But will the third plumber suggestion work?

ethicalpaul

I don't think it will, and also, turning off the service valve may result in problems because those valves will often allow steam to enter, but not allow condensate to leave.

make sure the baseboard is pitched toward the pipe and use a low capacity vent like a #4. But be aware the vent can only do so much—once the convector is full of steam, you can't control the velocity of steam entering it—it will enter as fast as the convector condenses the steam. But that's OK. In my experiments, steam doesn't stop condensate from returning even in a 1" pipe.

I don't subscribe to the idea that there is a blockage.

Big Ed_4

Try putting scotch tape under the vent cap and poking a hole trough the tape to make a smaller vent .

To shut down a radiator you want to remove the vent and install a plug . Shutting the service valve , there is a chance of filling up the radiator with condensate and turning it into a water fountain ..

Insulation on the main solves many problems …

erics_guerron123

https://forum.heatinghelp.com/discussion/comment/1887821#Comment_1887821

So what do you recommend I do? I believe the radiator is not draining the water back down the service pipe. do you recommend a hoffman 41 air valve, which has a very slow venting ability. im just worried that by using a hoffman 41, the radiator wont heat up enough.

tcassano87

these baseboard are problematic with water regardless but that concentric reducer is 100% preventing some condensate water from going back.

Increasing it to 1-1/4 like the drawing would definitely help. But those air valves would probably end up spitting water eventually

erics_guerron123

https://forum.heatinghelp.com/discussion/comment/1887828#Comment_1887828

do you recommend a hoffman 41 air valve, which has a very slow venting ability. im just worried that by using a hoffman 41, the radiator wont heat up enough. i have a hoffman 41, #4 or #5 air valve that i can use.

tcassano87

https://forum.heatinghelp.com/discussion/comment/1887829#Comment_1887829

I don’t believe it would be an issue, could also try a VariValve, a lot of people don’t like them since they don’t have as long of a lifespan. But you can then slowly adjust it little by little to allow as much as out as you want. Start barely open and work up

patrykrebisz

what s the boiler pressure?

if it s low, then see if the baseboard is pitched towards entrance; replace the vent orfice to the pinhole size

erics_guerron123

https://forum.heatinghelp.com/discussion/comment/1887833#Comment_1887833

boiler pressure is set to lowest setting on pressuretrol….baseboard is pitched. when i installed a hoffman 41 (which has a very small orifice, it still spat water.

Big Ed_4

I am assuming there is no insulation on the mains ?

Big Ed_4

Try the tape and pin trick ..

Grallert

Where is this convector located on the main? First last? When was it added? and can we see the system? and the boiler?

erics_guerron123

https://forum.heatinghelp.com/discussion/comment/1887896#Comment_1887896

last of the main on the first floor.

4GenPlumber

3rd plumber idea is the first step. Actually the second. First ensure proper pitch back to the valve and pressure on the system. Then take away the puddle being produced by the coupling. If it still spits, run a return from the vent side down to the wet return. Good luck.

dabrakeman

I would suggest doing this incrementally. There are certainly some easy steps you can take yourself and if they don't work get plumber #3.

1. Make sure the supply valve is completely open
2. Verify you are not surging back at the boiler which would throw more water up into your mains. If so may need to skim
3. Verify you have adequate pipe pitches in the main as well as the runout to the radiator.
4. What do you have for main venting and pipe insulation
5. Try raising that vent up 8 inches or so. Easy enough since it is a straight vent.
6. If that all fails to give adequate performance then move forward with plumber #3