Vacuum Issues

esobel

We just installed a new scotch marine 4-pass boiler with a new vacuum system by Mepco and boiler feed unit in Manhattan. The header design is where it comes out of the top of the boiler, turns left, then turns towards the back of the boiler, then elbows down (full size elbow) then reduces approx. 1' above the normal water line and becomes a drip to the bottom tap of the boiler. On the horizontal run we have a tee that runs up to the main distribution header in the boiler room. What we are experiencing is a condition when the boiler is on or off, (no steam on the boiler) if we put the vacuum pump on the water drops out of the glass. I installed 6-1" swing check valves on the control piping at the top of the boiler and one on the feed line from the boiler feed unit. When the condensate pumps from the vacuum unit comes on even if the vacuum pumps are off I can hear the check valves singing. Oh did I mention there is no registerable vacuum on the gauges and I have several. The funny part is that the boiler does not flood after the cycle. All of the riser traps were changed and the radiator traps were changed as well.
Anyone have any solutions?

nicholas bonham-carter

A diagram of the system would help enormously, including the location of these riser traps. Then we can help.--NBC

EBEBRATT-Ed

Need pictures, something is not right. Your getting a vacuum on the boiler and you shouldn't be. The vacuum pump is supposed to be pulling a vacuum on the return lines, not the boiler. Yes, if the vac pumps are running you may get a vacuum in the boiler if it is off and your steam traps are cold and open but that doesn't explain the loss of water from the boiler. I would suspect a bad check valve in the feed water piping but without pictures can't tell