Water pouring out of main vent

Jay4334

I recently replaced all of my Trane B1 trap cage units as well as the end of main Hoffman 55 F&T trap. Heat throughout the house has improved quite a bit and very uniform from room to room now. Problem is I need a venting solution. Since the trap have been replaced I have lots of water gurgling (no banging) coming from the rads during cycles. Below is a picture of my current end of main setup (yes ends are capped because water pours out for some reason). I have an all stone colonial which the mains (steam & return) run parallel around the perimeter of my basement. From the boiler to the F&T trap there is 100' of 2" supply completely insulated....and starting from the first radiator to the main vent located above the end of main F&T trap there is 60' of 3/4" return and the last 22' it transitions in 1" return. The drop for the return loop as shown in the picture is 7" before it drops to the floor and returns to the Hartford loop & boiler about 7-8' ft away. Can someone suggest venting options? Explain why if uncapped the current setup will pour out water? (The water does not escape the venting shown until just about the last minute of a boiler cycle - also if I let it it would pretty much drain the boiler of water before it stopped pouring out) For that much water to be coming out it seems only logical that the water is coming up from the return loop? Likely/possible? (Boiler pressuretrol is on its lowest setting and does not register on the standard 0-30 gauge) Any help or suggestions would be greatly appreciated. Thank you.

Jamie Hall

The most likely problem

by far is excessive pressure backing water out of the boiler into the return.



I've got to admit that I'm not super keen on the particular piping arrangement you have there -- I'd much rather see the end of the steam main drip independently to the wet return, and the dry return drip independently to the wet return; then you wouldn't need the F&T at all unless you are depending on the F&T to vent the steam main into the dry return and thence to the regular vents?



Anyway, the only way water can get pushed up to those vents is for the pressure in the boiler to push it there.  This suggests that the first thing you want to do is to make sure that the pressuretrol really is shutting off the boiler at 1.5 to 2.0 psi -- and double check how high those vents are above the normal water line (1 psi will raise the water in the return about 26 inches).  Take the pressuretrol off and make sure the pigtail is free of any obstruction, and that the entrance to the pressuretrol itself is clear as well.



The 0 to 30 psi gauge probably won't show anything useful at that pressure (you have to have it for insurance and code compliance); you might want to get a 0 to 3 psi gauge and mount it on the same pigtail as the pressuretrol to really see what is happening.

Jay4334

Jamie

I disconnected the pressuretrol and had ink colored water/residue and two small apple sauce like blobs come out of the tee. Couldn't get the gauge off, but maybe later I will try spinning off the pigtail from the boiler and go that route. The height of the water line is 28" and the top of the venting configuration is 84". I did notice the differential was set at 2 so I turned it back down to 1. The water that comes out off the vent with cap off is cold. I am not entirely sure I follow you regarding the return piping....could you attach a picture or link showing the above mentioned layout. Thanks again

Jay4334

Venting Rate

How quickly should a main vent? How is the venting rate or vent itself effected by the pressure the system is operating at? Do the venting calculation take into account for air in or size of returns? ( I would think not but, Im new to this so not entirely sure). I have 100' of 2" steam main fully insulated until it hits the F&T trap at the end of the main. If I am correct that is 2.18cuft of air that needs to be vented. If returns need to be calculated I have 60' of 3/4" return and then a transition to 22' of 1" return for a total of 0.21cuft (if I am correct). Should the supply lines off the main and up to the rads be taking into consideration when calculating vent rate? I see that Gorton #2 seems to be the standard for main venting. Can anyone tell me the rate at which they vent? My system has pressuretrol set at .5 with a 1lb diff. I need to add a 0-3lb gauge because the standard 0-30 doesnt move like most report on these boards. Can someone tell me what differences in venting are there @ .5lb and 1.5lb? Also any insight on the original questions of this thread would be very helpful



Thank you.