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Question:

What are the steps involved in flushing a hot water boiler?

I flushed our hot water boiler on Wednesday by opening the drain valve until the water ran clear and then closing it again. Now it seems there's no water pressure in the boiler, and our radiators are cold despite the thermostat indicating that the heat is on (I've since shut it off to save gas until I figure this out). Is there another valve I have to open/close to refill the tank?

Answer:

When you did that you added fresh water in the system and fresh water has air it it. You have to bleed all the air out of the radiators. Start with the furthest one and work your way back to the boiler. If you have a expansion tank on or around your boiler do not let the air out of it.
When you did that you added fresh water in the system and fresh water has air it it. You have to bleed all the air out of the radiators. Start with the furthest one and work your way back to the boiler. If you have a expansion tank on or around your boiler do not let the air out of it. It will have a bicycle air valve on it covered by a plastic cap. Don't touch this unless you already did then you will have to get an air pump and pump air back into it. If you have no pressure in the system you can't bleed out the air. Make sure your circulating pump is working also or you will have no heat. Hope this helps.
balance expansion tank

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