home boiler trouble

[jimmy]

Before I go into deep detail here I am putting this question out just in case there may be something I overlooked. I installed this boiler and controls (complete) 35 years ago and maintained it ever since, I am familiar with pressures, flows, etc. Last winter I shut off my supply valve to the regulator 12#, after shutting down the boiler my pressure dropped off to 0 psi. I visibly checked through 2 zones and found no leakage, it kept doing this and still does. I removed the automatic vent valve above the flow valve, also removed the expansion tank. Plugged the 1/8th inch outlet and used the 1/2 inch to connect a line adding

21# of air. This kept solid for 24 hours, after visual checks and pressure test I am 100 % confident no leaks in the system are present

There is also no indication of leakage in the boiler, I removed skin, cleaned and checked all I could see, I did not want to remove the outlet hood above the boiler tubes as it was cemented to the water jacket.

I have been hearing a slight gurgling for sometime, inside the boiler. I am aware noises can travel, however I am certain this gurgling is from the boiler internals. All air has and is purged from all the vent valves in the system. along with the automatic vent valve.

Now here's a kicker that just happened today. Yesterday I add water to bring up pressure to

12# (from 7#) it went down to 7 again as it has been, and then it actually went back up to 10lbs...

Valves around regulating valves are closed and do not leak through.. Is it possible I somehow have air trapped in the boiler cavity that will not vent?. I am trying to keep from spending $3- 4000 for another boiler unless absolutely necessary. If I need to my next question I will post in greater detail thanks

[ransley]

For all good boiler pros go to

and post at Off The Wall, for all boiler Hoes go to althvac for a reaming. If its not leaking it doesnt need replacement but I have no idea of your problem. The guy who runs Heating Help, Houlihan, has written a few books connsidered must reads for steam systems. You will get the answer there.

[Ed Pawlowski]

"jimmy" wrote

I'd suspect the feed valve is not holding as well as you think or there is air trapped in the system. Could be from the water giving off gas from the chlorine or oxygen in the water.

As for spending the money for a new boiler, after 35 years, it may be "free". Energy tax credits, fuel savings, rebates, no interest financing are all available. I put in a new oil fired boiler and cut my fuel use by

38% over the 30 year old unit I had. I put in a System 2000 from Pays for itself in savings.

[Van Chocstraw]

It's the regulator. Air or no air it should maintain the same pressure. The gurgling is air, probably in the zones. You need to bleed the air out at all high points in the system. The baseboards or radiators should have bleeders.

[jimmy]

Everything suggested so far has been covered and is ok...as I stated there is no air in the zones, I have a bleeder on every rising elbow. When I say no pressure is present at the closed inlet valve, I mean no pressure because the 2 valves around the regulating valve is closed and drain plug is removed.. The expansion tank is new and holding at 12# Ransley...your idea was great, I have posted this question on that site and getting feedback. New expansion tank directions indicate it should be installed on inlet side of the pump. I installed this on the outlet side of the boiler exactly opposite of how this one indicates it should be installed, been working since 1977. Thats a puzzling one also.