overfeeding steam boiler

Jim Pompetti

Crown boiler (steam) BS1380ENPZPSU , has been overfeeding it has a Cyclegerd CG400-2090 with a ZXT-24 (which is displaying 000 all the time .Has anyone had this or similar problem.

Fred

Is supply water leaking past the bypass valve? It has to overfill from either a auto feed and the meter isn't registering it or the supply valve.

nicholas bonham-carter

Is there a hot water coil in the boiler, which may be leaking?—NBC

Jim Pompetti

NO . New install

Steamhead

Either the bypass valve is leaking or the valve in the VXT is. Try taking apart and flushing out the VXT valve and see if that helps.

Big Ed_4

Cut the feed lines below the valves and see if any are leaking .. Called the union test ...

GBart

Damn dry base boilers should be outlawed.

GBart

They don't hold a lot of water, you could be running low on a cycle just to fill the system with steam and then the auto feed comes on then at end of cycle when the condensate returns you are over full.

You would have to witness it to be sure, set a delay for fill on the VXT, that's why that option exists.

nicholas bonham-carter

I would think that every boiler, rated for steam should have enough water content to fill the system, with steam, without needing to trip the LWCO, UNLESS the pressure is so high that a substantial portion of the water is pushed up into the dry returns.
Weil McClain must have been a little weak on water content, because they showed the alternative reservoir tank piping on some boilers.—NBC

GBart

Unknown, I've seen small dry base boilers and wet base put into large homes that did not have enough volume to fill the system and have enough water still in the boiler. Seen systems with slow condensate return due to old piping.

This type of problem needs baby sitting, several cycles need to be observed and what is happening will present itself.

Jamie Hall

I don't buy it. Let's suppose that for some unfathomable reason the radiation in the building is the least efficient, in terms of surface are for a volume -- a cube. And let's suppose that that cube has an EDR of 1200 square feet. Now That cube will have a volume of approximately 3000 cubic feet. To fill that volume would take 1.7 cubic feet -- or about 13 gallons. Granted, that's a lot of water. But is our radiation ever so inefficient? Let's suppose instead that it's in a more feasible shape -- say a panel radiator, double faced, with an inch between panels. That's still a pretty big panel -- 24 feet on a side. But the enclosed volume is only 50 cubic feet, which equates to only 0.2 gallons of water converted into steam.

I don't see how, even with a really small boiler, one can claim that because the boiler doesn't have enough water volume that you will have trouble because it can't fill the system with steam.

Where you can have trouble is with slow wet returns. It's not a bit difficult to visualize a scenario with a few gallons of water backed up in a slow return. It's even less difficult if the pressure is high enough to back into what should be a dry return.