Recently we had some repairs done on our house oil fired heater it was a forced water valve or something like that. Now it leaks water when the heater goes on from the pressure relive vaule. The service man came and said our pressure relive vale is leaking because expansion tank needs to be purged because the forced valve was not adjusted properly by the plumber. It was a junior plumber who said "I just put em' on, I don't adjust them". I deal with him later. Any way the service man wanted $311 WOW! to purge the expansion tank. I'm handy and asked him what he was going to do. He said he would hook up a hose to the expansion tank and blow air into it to get the vacuum released so the water would flow from the tank. Because there's no expansion tank relief valve on the tank.
Now, I just read you can do the same thing by doing the following:
•Turn off boiler, close water supply valve and let tank and system cool.
•The expansion tank purge valve will release water and let in air. Attach a hose to the purge valve and drain about 3 gallons of water.
•If there is no purge valve on an older tank, then shut off the valve between tank and boiler and totally drain expansion tank.
•Open water supply valves and let system fill back up.
•Turn boiler back on (do this after water supply is back on)
•System will recharge. Let run for 1-2 hours and recheck.
Any comments or suggestions please let me know
Thanks
Jim from PA
[email protected]

Looks good to me. Give it a try. You have nothing to loose. If it does not work call back the service man.