I need to change the hot and cold flexible water pipes feeding my bathroom sink as they are rusty and ready to burst. The problem is there are no shutoff valves under my sink so I'm wondering what the best course of action is.
I've read all the blogs I could find and found the information to be confusing as everyone had a different piece of advice.
- Some people say that shutting the main valve at the meter and draining the hot/cold water pipes is sufficient as long as the water heater is lower than the lowest hot tap that will be drained (hard to say for me as my water heater is on the ground floor)
- Some people say that the water heater cold water feeding pipe valve should be shut off
- Some people say the water heater should be turned off (gas, electricity) as a precaution
- Some people say the water heater might get siphoned out and therefore present a hazard, etc.
Can someone help me knowing that my bathroom is on the first floor and my water heater is on the ground floor? I realize I need a better understanding of the theory so if someone knows where to find some good information please let me know.
Best Answer
The water heater should have an vacuum relief valve, so no siphoning should happen. The water heater is designed to withstand a loss of pressure on the cold side without any problem, no matter if the hot tap is open or not.
Consider this: if you close the main shut-off, this has exactly the same effect if the water was turned upstream from you, on the street, or if the water main burst somewhere, etc. So this poses no hazard to you or your water heater, as these things happen from time to time, and your water heater is designed to handle them.
Just close your main water shut-off, open the taps you are changing water pipes for, both cold and hot, and let the water drain. Hopefully your main water shut-off is operational, and withing a couple of minutes, water stops flowing, then you may proceed. But wait till the water is completely stopped: any trickle may indicate that your main shut-off does not close properly.