How do I drain hot water lines without draining the water heater?
Posted on | April 19, 2010 | 3 Comments
I have a cabin that must have the water lines drained in winter, to avoid lots of plumbing problems in spring. This is a well with a partially underground pump, so the pump is fine, but the lines beyond the cutoff at the pump must be drained. The cold water is no problem, but getting the maximum amount of water out of the hot water lines without draining the water heater is my challenge.When I turn off the faucet at the tank, it causes some water to remain in the pipes. It is not possible to disconnect the pipe at the heater, and after leaving the heater, the pipes are inside the concrete floor and do not emerge until they reach the bathrooms, Next to the heater is a sink, but I don’t believe disconnecting that line will cause the others to drain either.
I will worry about the logistics if someone can explain the principle of why the one end being disconnected and the other being connected seems to form a partial siphon or vacuum or whatever it does.
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3 Responses to “How do I drain hot water lines without draining the water heater?”
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April 19th, 2010 @ 5:46 pm
shut the water off going into the hotwater heater and there should not be any pressure…and you dont need to worry about the hot water pipes leaking out more then they hold.
April 19th, 2010 @ 6:21 pm
What I would do considering your plumbing setup is to turn off the cold water, which is the input and you seem to know how to deal with it. Then I would disconnect the hotwater output on top of the water heater and open all the hot water faucets in the house and blow air into the flex line on top of the water heater. I am assuming it is a copper flexible line, some are hard plumbed, the air should blow out almost all of the water from the lines. There is another way this can be done, there is a special spring loaded check valve that can be buried in the ground and surrounded by gravel, this device opens up and drains water when pressure is relieved, or at about zero psi. These were invented for underground sprinkler systems, but can be used for other purposes. About the partial vacuum, the system has trapped air and can be relieved by opening the faucet that is the highest of the bunch prior to draining, of course this is with the water pressure turned off.
April 19th, 2010 @ 6:39 pm
you should be draining the water heater as part of winterizing. a long cold winter can freeze any and all water in the cabin — that includes the hot water heater and even the toilets. expansion of the freezing water in a contained space can lead to a ruptured pipe, water heater, or plumbing fixture. best to get out all the water you can — and don’t forget sprinkling systems ….