What does a gurgling, panting radiator look like? Watch this.

Chris_L

Since there have been a number of posts recently about noisy radiators, I thought I would post this video I took recently. I had one small, steam-only radiator that was doing a lot of panting, and would start gurgling after the boiler was on for about 10 minutes. No banging or water hammer, and the last two sections of the radiator would heat up much more slowly than the first two.

The gurgling was definitely near or in the radiator, but I couldn't tell where. So I temporarily put a clear nipple between the supply valve and spud and turned on the boiler. Here is what happened:
https://youtu.be/rCyIqHmZLLc
From this , I concluded the problem wasn't with the radiator or the valve--but what and where? The radiator is on the first floor, and while I couldn't see radiator riser from the basement because the ceiling has foam insulation, I could see that the run-out had good pitch where it connected to the riser.

I finally figured out what was causing this problem and will pull together some photos to show what is was. In the meantime, if anyone wants to venture any guesses, I'll give you two points for the correct answer.

JUGHNE

Riser too long....water in pipe under floor??

Dan_NJ

My guess would be gasket or chunks of it have fallen off and are sitting in the orifice.

Mike Cascio

Concentric reducer at the riser or down the line.

the_donut

Runout from second floor pitched wrong way.

newagedawn

water line to high, incorrect near boiler piping

Chris_L

So here was the problem:
@JUGHNE, yes it was water in the pipe, but nothing was wrong with the riser. I thought condensate might be collecting in the swing joint connected to the riser, so I dug out all the foam insulation and found this:

Oops, no swing joint there (should have checked the photos I took before having the ceiling foamed) and the riser couldn't be much shorter without the fitting hitting the subfloor.

So where was the water accumulating? Here is the pipe slope near the radiator:

Radiator and bubble in the level are to the left. Looks good.

Time to look at the rest of the runout, which is over 14 feet long, and here was the problem:

This is about 12 feet from the radiator, just before the runout passes over the central beam of the house to connect to the main. Main and bubble in the level are to the right. Looks bad. (Condensate has to run up hill against the steam.)
@the_donut, Yes, the runout was pitched the wrong way for a bit, but the dip was very close to the main (this is all on the first floor).

The fix was easy enough, just add a pipe hanger in the middle of the runout. (There were none before.)


Check the pitch:

Now the bubble is to the left and the main on the right.

And now this little radiator is as quiet as can be with no panting or gurgling:

JUGHNE

Very interesting video, neat to see. Glad your plastic didn't melt before the end.
Pretty long run out, but a pretty little rad.

So who gets the points....can we apply them to our Visa card

Chris_L

@JUGHNE, Thanks. You get to share the two points with @the_donut. No credit card required.

What surprised me is just how far the condensate was pushed--about 12 feet up the runout, which on average was well-pitched--almost 3" in 10', and then up the riser.

Not to blame the dead men, but the runout had no upward pitch where it connected to the 45 on the nipple to the main. The nipple connected to the main should have been pitched up a bit more to give the runout some upward pitch toward the radiator.

As for that clear plastic tube, yes, it was operating at well above its rated temperature. But I had boiled a piece of it in water first to see what would happen, and kept a close eye on it--but not too close--for the few minutes it was in use .

JUGHNE

I find it amazing that you say .2 PSI could move water that much up the riser into the rad.
It seems like you should have had hammer in that run out.
But between low pressure just being a bit of water it obviously did not happen.

BTY, thanks for the one point. When your married for about 40 years you are always looking for extra points.

gerry gill

excellent instruction video on pipe pitch. Thanks for posting that!

newagedawn

ah, good insight, thanks, i like the maid o mist vent, been using them lately they are working well

dbrown

Awesome video! That really helps explain why pitch is so important.

Did you use heat shrink to attach the plastic tube?

I'm so going to do this to one of my radiators to see what's going on.

Chris_L

@gerry gill , @newagedawn Thanks. I appreciate it.

@dbrown, I'll send you a private message. (That is not heat shrink.)

I haven't described how I hooked up the radiator because I don't want people getting hurt trying to do this themselves. I run my boiler at a very low pressure, and knew I wasn't experiencing water hammer.

If that wasn't the case, I wouldn't have tried this. If the plastic tube had come off, steam and hot water would have been blowing out the valve, with potentially disastrous consequences.