Spitting radiator

mikefullr10

Hey guys I have a couple of problem radiators that seem to be spitting a lot of water when the system has a long cycle.   I have checked the returns and have flushed them out and also the radiators. I’ve tried replacing the vents with vent rites and varivalves both still spit.  These a for a basement apartment and are down fed.  Does anyone have any other guesses on what it could be. I am stumped.  Check valves seem to be working 

neilc

is this a recent problem?
or forever on going?

what's the pressure at the boiler?

gerry gill

Looks like strange radiator piping to me. The steam can go to both ends of the radiator.

LS123

Although I am not a pro with steam piping, as @gerry gill mentioned, and @Hap_Hazzard agreeing, I am guessing what ever the remaining water may be getting pushed back in to the steam main pipe that feeds this rad... its like a endless loop of steam and water getting to the rad when Tstat calling for heat. Pic attached, highlighted in orange, may need to be removed or reconfigured. Is this a single line steam system?

mikefullr10

Thanks guys for the reply’s. It is a single pipe steam system.  It’s in a apartment/condo building.  The tenant is in the basement apartment and said it started last year but didn’t say anything.  It is the only apartment in the basement and the only one having a problem 

JUGHNE

This used to work OK?

Where does the small lower pipe, passing thru the wall, connect?

To a wet return, perhaps.

I wonder if this design, being down feed, is dripped into the return, the rad cond water goes into the same return.....but no steam traps.

I think perhaps the check valve holds water/steam back until enough pressure swings the internal flapper to drain.

If the check swing was sticking then the water could back up in the rad to spit out the air vents.

Have you opened the check valves for cleaning?
The paint still looks intact in the pictures.
That top plug can be a bear to remove sometimes. It is brass with easily rounded corners on the hex.

Not difficult to replace with the union there.

Just an idea.

neilc

check, and report, your boiler pressure also,
pigtail clean?

neilc said:

what's the pressure at the boiler?

mikefullr10

Yes pigtail is clean boiler builds no pressure. The “drips” do go down into a wet return. I was thinking the same thing about the check valves.   I was thinking about taking them out if they are not needed but I am unsure 

JUGHNE

I think the check valve creates enough resistance to induce the steam to go into the radiator.
The condensate with the steam pressure builds up pressure to open the check for a "batch dump" of condensate into the wet return.

IIWM, I would crack the union and unscrew the check out of the piping.
You might be able to clean the check from each end and avoid the troublesome top cap.
Or just replace the check valve.

The horizontal pipe leading to the check could be full of surprises.

DanHolohan

Is the horizontal pipe below the radiator lower than the boiler's waterline?

mattmia2

DanHolohan said:

Is the horizontal pipe below the radiator lower than the boiler's waterline?

Or was it with the original boiler.

DanHolohan

Yes, it may have been heating with return condensate.

mikefullr10

The horizontal pipe under the radiator is above the water line. I think that it has always been heated with steam and not condensate. We did flush out the radiator about 2 weeks ago and haven’t had a problem since but it also hasn’t been that cold out so hopefully what ever was causing the clog was flushed out. If not next step is th take the check valves apart and see

JUGHNE

Perhaps the rad flush opened the check valve and flushed it also.

That looks like a lot of heater for basement apartments, plus the piping loss.

pedmec

well first of all you should confirm that what you are referring to as a check valve is a check valve. it could be a thermo disc thermostatic trap or equivalent, which is the how i'm leaning. considering the direction of flow for the condensate, should be going left to right, then i should be able to see the pin hinge for the flapper but i don't see it. should be right in front, full view.
you also said it was one pipe steam and radiator has two pipe arrangement. you might have a mongrul system. one and two pipe steam combined which i have in multiple buildings in boston. i would check the return piping arrangement. obviously the supply tee going into the radiator is just draining condensate into the return to dry out the supply steam but doesn't make much sense as you have a return on the other end. so my guess is you have had the pressurtrol settings increased or plugged returns. increasing the pressure on a system that has traps will cause stacking in the returns to increase due to the pressure drop increasing. need more pics

gerry gill

Could be a lift check also...either way its a real **** set up.

mattmia2

Nothing wrong with piping something 2 pipe in a 1 pipe system to solve a problem. As long as you do it correctly.

JUGHNE

 Check valves seem to be working 

as said by the OP.

The power of suggestion that these are check valves made me not look very close.

Yes, with closer examination, they do not look like check valves.

But could be some in line trap.

pedmec

so the question becomes is your system a combi one pipe/two pipe system? that radiator is a two pipe set up. so with a trap on the condensate return water has no pressure to help push back into the boiler. it needs to stack up to overcome the system operating pressure. what pressure are you operating at?

JUGHNE

Wouldn't the steam pressure in the radiator be pushing on the cond water?

pedmec

not if thats a steam trap (thermodisc) on the return. it closes when steam the hits it.

JUGHNE

Yes, if a trap, it closes on steam.
Then would the condensate stack up and cool the trap so as to open it and drain, with the steam pressure pushing it out into the wet return.
Until the steam closed the trap again.