Closed Hot Water System Fill Level and Pressure

John B Fowler

3 levels. 3 radiators in basement (upfeed to the single pipe) 5 on first floor, 4 on second floor. I'm guessing 80's on the grunfoos circulator. Thanks, John

John B Fowler

AS HW Boiler Fill Level, Pressure and Settings, Efficiency

Drained my 1946 AS single pipe mono tee closed, grunfoos pumped system to empty pressure tank adjacent boiler(no shutoff or vent. Refilled/bled all the radiators and then shutoff fill valve as it has always been (no regulator in line or backfill prevention. The original AS manual says on closed system to fill until the pressure valve dumps (valve is 30PSI!) I didn't go that high just to about 28 on the pressure pointer. Have run it for an hour, gauge shows Altitude fixed red at 24, Pressure moveable black is at 26 PSI and boiler temp is running 150. All radiators nice and warm and pump hums along.

Is this correct or what should I be doing? Should I have more water pressure or less, I thought I read something about top needles matching? I'm not convinced the altitude was correct because the dial is scratched as if poorly moved.

Second, this baby is older than me and has a big flue. Are there any adjustments/settings to make on aquastat (1947) or thermostat (recent honeywell round non-setback) to make this more efficient? Has a newer gas valve assembly with 2 standing pilots. Have heard adding a "scuttle" or "equalize air" in basement window would allow fresh air for combustion and "balance" air pressure in the house.

She keeps the house and basement toasty but gas won't be getting any cheaper. Thanks for you help and this great forum. Regards, John

escaseadjug1793177

How many levels are the radiators on? Newer boilers work well at 12 psi for 1-2 floors and if you have a third floor up to 17 psi. How long ago was the circulator added?