[phylly]

My husband and I just discovered that our hot water cylinder sprung a leak. Towards the top of the cylinder, the insulation looks like it burst outward, but we don't see the hole in the cylinder. There is water collecting between the insulation and the cylinder that we are able to keep contained. We think the insulation burst is due to the water build up between the insulation and cylinder.

Last Wednesday we changed the faucet in our kitchen. Originally, we had a faucet with separate hot and cold water controls/handles. It also kept the hot and cold water separate within the faucet. We replaced that faucet with a more modern Moen faucet that mixes the water in the faucet and has a single handle. We found, after switching the faucets, that the flow of hot water with the new faucet was very low. Also, swinging the handle toward the cold water side even slightly was enough to turn the water cold. My husband concluded that the cold water pressure was much stronger than the hot water and decided that the faucet wouldn't work on our system without a lot of additional work. We switch back to our original faucet tonight. When he went to turn the hot water back on he found the damp floor and burst hot water cylinder. Are the two things related? Did we cause the burst while trying to upgrade our faucet? What would cause the cylinder to pop?

Thanks in advance for any help or insight. Any suggestions as to what might cause the leak in the cylinder, if the two aren't related, would be appreciated too.

[KISS]

Let's assume that the "cylinder" is the "hot water heater".

It's possible, that the water heater was not turned off properly AND the "temperature/pressure" relief valve was broken. The T/P valve is usually on the side of the heater near the top with a length of pipe going to a drain. Look here: http://z.about.com/d/homerepair/1/0/.../T_P_Valve.jpg
You can lift the actuator of the t/p valve and water will come out the pipe. It may be hot, it might also get stuck. So be carwful. I'd do it will a cold tank.

I also don't know if your water heater is gas or electric or how you proceeded to do the installation, but I suspect the t/p relief valve was bad and whatever you did was an event that needed a t/p relief valve to work.

If you had to turn off the hot water at the tank, did the tank have 1 or 2 valves? Did you turn the gas to pilot or turn the electric off? Did you leave the faucets open after turning off the water? Did you let the air out of the lines before you turned on (electric or gas) the hot water heater?

[phylly]

If you had to turn off the hot water at the tank, did the tank have 1 or 2 valves? Did you turn the gas to pilot or turn the electric off? Did you leave the faucets open after turning off the water? Did you let the air out of the lines before you turned on (electric or gas) the hot water heater?

Sorry, I just realized that this is probably a U.S. forum. I just found this site while dealing with our hot water cylinder crisis, so I was a bit preoccupied when searching for helpful sites. I should have mentioned that we are in the UK. I don't know if our plumbing systems are very different. Our hot water cylinder/heater is located in the closet in one of our second story bathrooms. There is another tank in the attic that feeds in cold water to the tank in the bathroom where it is heated (electric) then sent around the house. I don't think we have the same kind of T/P valve that you mentioned, definitely not a valve on the tank that looks like the picture you included. The hot water cylinder has a pipe at the very top of the tank that runs back up to the tank in the attic should there be an overflow or pressure problem. The attic tank has a release/overflow pipe that leads out of the attic.

Before working on the kitchen faucet, we turned off the valve on the pipe that brings cold water from the attic tank into the hot water cylinder (This is not the same pipe I mentioned above. It runs from the attic tank into the bottom of the hot water cylinder) . After turning off the water, my husband opened the faucet in the bathroom where the cylinder is located, the downstairs bathroom faucet and the kitchen faucet before starting the exchange of faucets in the kitchen. We have another faucet in the second upstairs bathroom and one in the utility room that were not opened. Don't know about letting the air out of the lines before turning on the hot water heater. What do you need to do to let the air out?

Thanks for your quick response. Once again, sorry for not mentioning that we are in the UK. Hope I didn't waste your time.

[labman]

Perhaps people answering questions here need to recognize the world doesn't stop at the border of the USA. I sometimes struggle understanding dog questions from other countries.

If you left both the inlet and all the hot water taps closed and the heat on, the expansion could have burst the tank. If an old tank had a weak spot, it might give before reaching the pressure to open the T&P valve. Ordinarily they are best left alone. They depend on metal to metal seats and the least bit of dirt or lime makes them leak once opened. There is no repairing tanks, so it will have to be replaced. Here, new tanks come with new T&P valves.

Likely the problem with the new faucet was that in working on it, you knocked some crud loose and it was blocking the hot water port. It may have worked fine if you cleaned it.

[KISS]

We don't have such a system. In the US we have extremely large tanks that the utility pumps water in. I should take a picture of one. Then each individual house doesn't nned to gravity feed their plumbing. Wells work much differently.

Anytime the cold inlet to the hot water "cylinder" is off, the electric to the hot water heater must be off, but not vice versa. It's also best to leave a hot water faucet open too.

To bleed the air out of the lines. Open all the hot water taps a little in the entire house. The tub is a good one to open all the way. Slowly turn on the cold inlet and then close each tap starting from the closest to the water heater after all of the sputtering is complete. Turn the cold water inlet on full and check each tap again for sputtering.
Then turn on power to the water heater.

You don't have to do it exactly that way. Open a tub/shower the furthest away because it can make no mess when your not there. Turn on the water slowly until you hear no banging. Close the tub/shower taps when the sputtering stops and then check the branch taps.

It's very possible that the "low pressure" in the hot water line was really air in the lines.