draining heating system

[Cheeky]

i need to raise a baseboard heater, and need to figure out how to drain the heating system.

it's hot water, with baseboard radiators.

turn off the power....then find the shut-off valve, and drain?

[jcrenick]

You should have a drain valve in the lowest portion of your system. Make sure the supply is off and use the drain valve to lower the water level. Once the drain valve is open you can open a bleeder to make it go faster.

[jhart]

Depending on how far the drain is from your heating unit, you may want to attach a garden hose so it will go directly to the drain also. I probably would open a couple of bleeder valves if you have multi floors.

[scorrpio]

First, you need to determine if you can drain just a particular section of it. If your system is properly segmented with isolation and purge valves, you may be able to drain just that part - cause the less 'old water' you replace with new, the better.

Once you determined a section to drain, shut off valves going to it, run hose from purge valve to drain, open the valve. Most heating systems have 12-15psi cold static pressure. Once that is relieved, you can go and fully open the air vents in the baseboards. They should drain pretty quickly.


After you are done, it is critical to properly refill everything. A large air bubble in the pipes can wreak havoc if not pproperly purged.
Close all air vents, and very slowly open the isolation valves. Make sure someone observes the areas where you did work on baseboards. Brushing on some leak detectant is also a good idea - if there are leaks, there will be bubbles at the joints. This is far better to detect leaks now than have a jet of pressurised water spraying all over later.

If no leaks, work one baseboard at a time, opening their vents, letting air escape until water starts coming out.

Once that is done, it is a good idea to circulate the water in the baseboards. You system should have a main air separator/vent (usually near expansion tank) and you should see vent sputtering air now and then.

Once that vent stops sputtering air, go again baseboard to baseboard, opening their vents just a little bit letting air escape if present, and closing if water comes out.