oh the glory of steam

[Deleted User]

Sooo... for the first few months of the winter. Our steam system was working very well. We got rid of ALL of the loud clanks that we were experiencing the previous year by adjusting the tilt of the radiators and adjusting the vents on the radiators.

A few days, there must have been a power surge or something, because our boiler did not come on as it typically does in the morning. It started about 45 minutes later than normal. I think the power surge probably happened some time overnight so the heat had been off all night.

Anyway, now for the last couple of days, the clanking is back in 2 of the problematic radiators. Why would the boiler being down for longer then normal cause the clanking to return?

ethicalpaul

A longer than normal run cycle (after the downtime) could have resulted in more condensation than usual in some place in your pipes. This could be causing some water hammer. It seems to me it should clear up just as mysteriously as it arrived.

Only a 45 minute delay, however, doesn't seem like it should have resulted in a significantly longer run time upon its return...

You could look for the source of the clank and see if there are any sags or strange pipe configurations that could result in water pooling.

KC_Jones

If your system isn't "perfect" you will see differences in performance when it's starting from cold, versus warm, versus hot. On my system a cold or slightly warm start exposes a bit of expansion noise, but it doesn't happen often. One day I will "catch it" and figure out how to fix it.