Boiler Pressure

[wev567]

I have a six year old Lennox Conservator 90 (made by Dunkirk) hot water boiler. I seem to have little water pressure in the system. The system gauge reads about 120 degrees and maybe 3 or 4 psi. Past years it's read a bit over 10 at that temp. I can bleed a second floor radiator, and get water after a few tries, but that same radiator will need bleeding in about an hour. The furthest, highest radiators are cold.

Is this just an adjustment problem or something more serious? Is there a way to check the pump? It is an external Taco cartridge pump. Could one of the bleeders not be sealing? Could the pressure reducing valve be bad? Any suggestions? TIA

[LazyPup]

The pressure gage on your system is calibrated as a PSIG gage, which means it measures pressure in pounds per square inch above standard atmospheric pressure. Understanding that the internal pressure is 10psi greater than the atmospheric pressure surrounding the vessel or the piping system it would then stand that it is a physical impossibility for atmospheric air to be entering through a bleeder port.

In turn, your house water line pressure is somewhere between 40 and 85psig which is somewhere between 2.72 and 5.78 times standard atmospheric pressure at sea level. If the water pressure reducing valve were to fail the internal working pressure of the system would rise to the line pressure of the water, which is well above the maximum allowable working pressure of your heating system.

It is remotely possible entrained air in makeup water is being released in the boiler, but under normal circumstances the heating system is a closed loop and should not be getting any appreciable amount of additional water. Surely not enough to convey enough entrained air to cause the type of problem you are describing.

It is possible that your system was drained for maintenance during the off heating season and the air was not properly purged out of the system during the subsequent startup procedure.

It is also possible that you have a leak in your system and while it sat static during the warmer months some water leaked out and was replaced by atmospheric air, but here again, the system should have been purged of air during the season startup.

The TACO circulator pump can be easily tested by using a snap on amp meter (an Amprobe meter) to measure the amperage when the pump is running. If the pump is drawing the correct amperage as specified on the manufacturers data plate the pump is pumping at full capacity.

The operating pressure of your boiler is determined by the "Pressuretrol" pressure temperature control unit, however for safety reasons making adjustments to a boiler pressure control should only be done by a trained technician.

[wev567]

Right now the gauge reads zero, so I guess the reducing valve is working. I have heat in all 1st floor and in a 2nd floor radiator directly above the boiler. Would that point to a leak in the rear of the house, the part furthest away. I guess it's time to call for service. Would the system fire if the "Pressuretrol" is malfunctioning? This system has a lot of electronics. Or is it not that fancy?