for Cold Climate Housing and much more

Last Updated: , Created: Saturday, October 6th, 2001

When I turn on the cold water faucet, it runs hot for a minute, why?

Judy from Stoney Creek, Ontario is baffled by the fact that her cold water is hot, at least for the first few seconds of running.

Faucets that combine the hot and cold water to come out of a single spout are of two basic varieties: two completely separate valves each feeding the spout, or a combined single level spout where all the water mixing goes on inside the valve itself. In this case, it is possible for the little washers that would normally keep the water from flowing anywhere in the valve other than out the spout, can have problems either with the washers themselves or the sliding piece they fit against. If a groove has formed connecting the hot to cold it is possible for these two to connect without any leak outside of the valve. If you leave it sit for a while without using it, the hot water from the hot water tank will try to rise up in the house and will cross over, slowly filling the cold water side with hot water -- they are both under the same pressure so this is just a convection flow of hot water. Open the valve to send water out the spout and both sides flow up, but the first bit of water in the cold side is now hot.

Initial hot water out of the cold side of a single handle faucet is usually a sign of a need for repair or replacement of the mixing valve inside the faucet.


Keywords: Faucets, Water, Mystery, Washer, Plumbing, Problems, Valves

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