Illinois vapor system problems

herbh

Have this system in field. System has return trap and vapair trap. Does not have check valve at top of vapair trap, only open vent at 45* angle. Based on old schematic drawings, check valves are in correct places. No crossover air vents found. Radiators traps checked out well. Customer complaint that on morning startup to daytime temp, 65 to 68. Water shoots out of vapair trap. Only time of day it happens. Vaporstat installed and set 6oz 1oz differential . Pigtail clear. I recreated condition after running boiler for long time. Gauge glass on return trap filled to top, then spilled from vapair vent. Any suggestions? Thanks, Herb

EricBaisch

I have a vapor system (Webster R) and even on long cycles pressure is under a couple ounces and water never raises to return trap which is below the main vent. That said when boiler was first installed and needed skimming water was forced from the boiler and up into the return trap, so based on my own experience I would say skim, skim more, and then skim more yet and then pressure in boiler should settle down and water will not be forced out the vent. My pressure gauge on my boiler is 0-6 inches of water which lets me monitor what is happening with my boiler very well. Normal operation is 2 inches of water but if boiler starts surging and forcing water out the gauge pegs and my code pressure gauge reads a couple psi. Skimming solves this.

Steamhead

I don't think setback is the problem here.

@herbh , does the steam line going to the return trap get hot right away when the boiler starts making steam?

herbh

The steam line never gets hot. Opened the union between steam
main and trap with gauge glass and steam is present. It never enters trap

Jamie Hall

No crossover traps between the mains and the returns? How, then, are the mains vented?