Gush
Lets say you live in a house with hydronic heating. It’s 6am on the coldest morning of the year, just above 20 degrees F, and suddenly a strange sound fills the bedroom, waking you from a light slumber. Could it be ice sliding down the roof? No, it sounds too watery to be that. Could it be a sudden downpour of rain? No, it’s too cold to be that. Could it be… oh shit. The heat! The goddamn hot water radiant heat! It’s a leak! I pull on my robe, slip into my slippers, and tear downstairs to the garage where the boiler lives. There’s a stream of hot water flowing out the garage door and more water pouring down from god-knows-what. It’s a gusher.
I admit to being mechanically disinclined, but even so my hydronic heating system, that normally does its job perfectly and without complaint, is a complex beast. The last heating engineering who inspected the thing told me so. I’m completely baffled by it’s workings, so when I see water gushing from a pipe above and slightly to the side of the boiler I panic and run upstairs to turn the thermostat down. Hey, smart guy, turning down the thermostat will not stop a leak! After a couple of head-scratching minutes I remember the electric switch that shuts the whole thing off. Brilliant. So it’s off now but there’s still water spewing out of a pipe. I quickly take inventory of all the little red and yellow levers, valve controls, but the labels on each lever are meaningless to me. Some read “Made in Italy”. I curse and choose the biggest lever closest to where the water seems to be leaking. No effect. More curses. Then I decide to call the heating company, hoping they’ve got someone ready to answer the phone at 6:20am on the coldest day of the year. They do, but she’s not terribly helpful, just tells me that an technician will call me soon. Meanwhile, I think I’ve isolated where the leak is coming from. It appears the bleeder valve at the top of the expansion tank is the source. (I know it’s the expansion tank because it is labeled “expansion tank”.) I grab some pliers and tighten the bleeder valve. The leak stops. Hooray!
But I now I have an even bigger problem. The boiler is off and it is very cold outside. I can’t start the boiler again with the bleeder valve closed or all the air that’s been introduced into the system will clog up the radiators. I’m also not confident that the bleeder valve will stay closed if I rev up the boiler again. I have to wait for the heating technician to arrive and fix it.
By 9am it’s 64 degrees in the house. Luckily, the sun comes out and warms the south facing rooms. I feel grateful to have good insulation. As it turns out, the sun and insulation keep the house from dropping below 64 degrees until 12:30pm, at which point, the technician arrives and saves the day. The culprit was a failed rubber O-ring in the weird device that is supposed to vent air out of the water circulation system. By 2pm the heat is on again and slowly bringing up room temperature.
There’s much sloshing of water to be heard now as little by little air is vented out of circulation, and I’m told that the air should be fully vented within a couple of days. I sure hope that’s the case. Each time the boiler kicks in it sounds as if I’m in the belly of a whale as she gulps in a thousand gallons of seawater. But at least it’s warm in here.