In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
I have an old vacuum system that I've been trying to restore for the past few years. With the help of some more-than-competent plumbers--some who post here regularly (thanks Dave and Charles!)--we have made vast improvements to the system. We are heating evenly at low pressure and the vacuum system is back on line after many years of being out of service.
That said I have been chasing down vacuum leaks for the past couple of heating seasons, and though I have made significant improvement (it could hold a 2"hg vacuum for about 20 sec and now go for about five minutes) it is still quite leaky. The way I have been operating it is that I manually turn on the vacuum on the coldest days during the shoulder months and let it pump away continually for the really cold spells. I'm not sure if it can be wired so that the vacuum pump comes on only during a call for heat but the pumps are still actuated by the floats in the receiver at all times. It takes about 15 min. to evacuate the system to 2" hg, but maybe it is enough that it is pulling air only at start up?
Here's my main question, though: does anyone have a good method to quickly identify and seal vacuum leaks? I have been using a mechanics stethoscope, which has not provided sure-fire results, and it turns out than many of the leaks we've had are from less-than-perfect-seals at the thermostatic trap covers (we did complete gut replacements a couple years back) As well, I think I that one or more of the boiler sections is leaking air into the combustion chamber (I can detect a ssssssss through the rear of the boiler vent only when pulling a vacuum), yet I have not seen steam coming out the chimney in any significant way. The boiler has been abused and may not have many years left in it, but I'd like to keep it going for as long as I can. Can anyone recommend a cleaner/stop-leak product combo that I might have decent results with at this point? I've been looking at the Hercules products.
I figured now that spring is here I would have a chance to completely fill the boiler and bring it up to temp with the proper stop-leak product, then flush and fill, cycle it a couple of times and let it rest. That might give me an opportunity to chase down more leaks in the summer with only the pump(s). I know nothing about these products, however, and do not want to do more harm than good.