Picture group flash steam hammer on wet-dry return

dlampe · March 5

mend of dry return and one-way check valve

Condensate is flashing over at this point and check valve is being slammed shut by the force rapid fire like emptying the clip on an AR-15 tap,tap,………tap.

dry return to wet return transition

near boiler piping and controls working as atmospheric boiler 2.5 lbs pressure below 2.5 lbs pressuretroll doesn’t turn on house gets cold.

series 63 peerless

near boiler piping and king valves

End of main steam trap is for air venting to dry return.

Jamie Hall · March 5

What pressure is that system running at? Most systems — not all — which have crossover traps were also vapour systems — very low pressure — and I'm wondering if your water hammer problem on that short horizontal pipe in the condensate drip which you show may be such that steam pressure in the mains is backing water up into it, since the dry return for which it is a drip will be at atmospheric, or should be.

It may even be high enough that steam is pushing through your "wet" return from the steam main drip right next to it, condensing, and causing the problem.

Check your cutout pressure — it probably should be less than 8 OUNCES per square inch, and certainly less than 1 POUND.

mattmia2 · March 5

unless there is a vacuum pump i doubt that the condensate is flashing to steam after it has had a fair bit of piping to cool it down. Much more likely there is steam in the returns and the water is encountering that.

If it is a vapor system and the boiler is oversized or some radiators are closed that pressuretorl won't adequately control the pressure.

EdTheHeaterMan · March 5

Picture group flash steam hammer on wet-dry return

So you have a picture that you needed to use a Flash camera to take a group shot of all your friends holding hammers, near your steam boiler? You can try a faster film like Kodak Tri-X 400. It is a black and white film but it has an ASA number of 400. That means you may not need a flash on your camera in low light conditions.

Hope this helps, and hope I didn't misunderstand anything

Jamie Hall · March 5

https://forum.heatinghelp.com/discussion/comment/1890653#Comment_1890653

Indeed. In fact, looking at all the pictures again and kind of eye-balling elevations, I'll go with my first comment: steam is going down that drip, thr9ugh a bit of wet return, and back up the return drip into that horizontal bit. Where it condenses and you get water hammer — repetitive, as the water level bounces.

Vapourstat time.

dlampe · March 13

there’s a vacuum pump on the system it’s not on.

Plumber says it’s broken down or not working.

Banging at the wet return was worse than ever with no check valves installed. If not flash to steam then why the banging? If water has enough weight from A dimension and check valve opens but slam’s shut in rapid fire or without the valve and hammering more than what’s the problem?

mattmia2 · March 13

steam encountering water and collapsing

the water cools the steam and makes it condense in to liquid water and suddenly have 1/1700th the volume of the steam which produces a partial vacuum and propels water around the system and makes the water hammer.

Jamie Hall · March 13

I doubt very much that you have a flash steam problem. Not saying you don't, but it's rare.

I still wonder about what pressure your are running this system at. I can't see all the piping, but I see — and mentioned — at least one place where any pressure over half a pound per square inch is going to cause problems and possibly severe water hammer.

To be clear, this isn't a flash steam problem — although it's vaguely similar. If you are getting steam pushing through from your steam main, down a drip to a wet return and then back up the next drip into a dry return, when the steam hits that dry return it is going to condense. And that, as has been said, will create a momentary vacuum. Which will pull water up from the wet return and slam it violently into the next possible elbow.

Let's find out what the system pressure is…

109A_5 · March 14

No thermostatically controlled zone valves ?

I see two mains at the boiler, one dry return ?

Why a vacuum pump and a vacuum break (Red arrow), that seems counter productive. Vacuum can enhance a system but it has to be utilized correctly.

Any other old specialized vapor system type equipment present ?

Why the need for the check valve ? With pressure oscillations it going to rattle.

You could take out the flapper, remove top cover (Orange arrow), remove the flapper hinge pin (Yellow arrow), remove flapper, reassemble hinge pin and top cover. See if the noise go away and the system performance is normal.

If the pressuretrol is intermittent increase the pressure adjustment at turn or two.

I'd be curious about;

Boiler size and system EDR. If you are building pressure they may not match well.

Main venting.

Picture group flash steam hammer on wet-dry return

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