When I moved into my 50 year old house about 4 years ago, there were icemaker valves on the upper heating zone loop, presumably for purging air out of the system. A couple of years ago a heating tech replaced them with bleeder valves. (He also replaced the Fill-Trol unit and serviced the boiler) If I recall correctly, one of the bleeders leaked so he came back and removed it, leaving just one bleeder. Then, at the end of last winter I checked and noticed a very slow leak in the area in which the bleeder was removed. This is not my main heating system and it was almost spring so I decided to just drain some pressure from the boiler and leave it for a while. Now with 30 degree temperatures in NJ, I need to resolve this. I figured I would pressurize the system again and monitor closely for the same leak. I have never pressurized the system myself before.
Here is what I did....
-Lowered thermostats (disconnected for one of the zones that has been having the problem
-Turned off gas supply to boiler (probably should have done this a long time ago)
-Turned off electricity supply to boiler
-Ensured hose valves for both zones were closed
-Closed refill supply line valve
-Moved thermostat controlled electronic valves into manually open position for both zones. (Note: Forgot to do this the first time I went through this process)
-Attached hoses to each of the zonesí hose connections (one on each return leg) and hung them so they were submerged in water in a clean garbage pail
-Opened hose valves on both zones
-Opened refill supply line valve
-Allowed water to flow through the system (both hoses) and into the garbage pail.
-When garbage can was full, turned off refill supply valve, then turned off hose valves.
-Carefuly turned on refill supply valve (with hose connections still closed) to *TRY* to bring the pressure up into the 12-15 psi range.
When I turned on the refill supply valve in the last step, the pressure quickly increased to 10psi. However, I could not get the pressure to increase beyond 10psi.
Also, although air bubbles stopped coming out of the upstairs / attic zone, there were still air bubbles (some large) coming out of the downstairs / family room zone. These did reduce down to just a stream of very small bubbles, but did not seem to disappear 100%.
So, here are my questions...
1. Am I doing this right?
2. Is 10 psi acceptable and normal? Since the Fill-Trol is supposed to be charged to 12psi, maybe this is just a minor error in the boiler pressure gauge and means that the Fill-Trol is actually working correctly? I vaguely recall a couple of heating guys in the past complaining that they could not get the pressure up through the supply line so they "worked around it", I think by hooking up a garden hose somewhere to the system). However, with the replacement of the Fill-Trol, I don't understand why there would still be a problem.
3. How can I be sure the air is out of the system? There is some kind of bleeder valve in the upstairs baseboard loop. It looks like it has a flat head slot on it. With the system cold, I turned it counter clockwise and it seemed to loosen, but nothing happened. Am I doing this right? Does the system need to be hot for this to work?
Any help would be greatly appreciated.