[jmanning]

Our house is about 7 years old. We have a brand new water heater installed just a few months ago. Water pressure is good. Since before the new water heater was installed, we have to run cold water somewhere else in the house in order to get hot water to run. So when I take a shower in the morning, I turn on the cold water in the bathtub, and the water to the sink and shower are hot.

Any ideas on what is wrong?

BTW. We are on city water

 

[gearheadon44s]

So do you not have any water or is it just not hot? Does it just take a lot to warm up? Is it an on demand sometimes if you have 1 central hot water heater they take longer to get the hot water than tank heaters. Buy turning on another faucet you are running twice the water through it.

 

[jmanning]

So do you not have any water or is it just not hot? Does it just take a lot to warm up? Is it an on demand sometimes if you have 1 central hot water heater they take longer to get the hot water than tank heaters. Buy turning on another faucet you are running twice the water through it.

We get water, it is just cold. And will never get hot as long as you run it. With the cold running, the faucet running hot water will get hot in a normal amount of time.

 

[gearheadon44s]

Is it tankless or on demand.

 

[gearheadon44s]

Sometimes the tankless or on demand systems have a threshold of water that has to move through them before the turn on. If you have extreme water saver heads you might be into it. But I wouldn't think so. I think you need call the installer.

 

[jmanning]

It is a gas 50 gal tank water heater

 

[gearheadon44s]

I don't know how but sound like some plumbing got crossed.

 

[charliemeyer007]

My guess is there is a cross over valve for like a water softener that is open/shut that was shut/open before the water heater change out.

 

[cj06]

Some one could have crossed a cold water
line back into the hot side down stream of
the water heater ?

 

[Wubboy]

Scald protection on the shower controls getting in the way of letting you get to your desired temp?

Wub

 

[Slclarry]

Hard to help without seeing it. Do you have a temp mix valve in the hot water supply? It possibly could be causing this.

 

[franklin]

I had a problem like that in a new house I bought. Turned out the hot and cold were connected together after the water heater. I think in my case the plumbers intended to put a valve in to be used for scalding control but never ended up putting it in. This left the hot and cold cross connected.

 

[jmanning]

I know very little about plumbing. I swapped out the water heater myself. I do know that when I did, if you just turned of the cold water supply line to the water heater and disconnected the supply line, water would come out of the water heater. There is a second valve in an area below the water heater that turns this off and the water to the house. I will take some pics of that area later and post them.

 

[charliemeyer007]

Is the cold water line on the In side and the Hot water line on the outside? I think your tube inside the water heater that takes the cold water in to the bottom of the tank is cracked/broken/missing and the water just flows straight across instead of pushing the hot water up and out the pipe.

 

[Packermudgeon]

Yeah, your shower is far away from the water heater. All the standing water in the pipe between the water heater and your shower is cold. So first you have to run out the cold water, then you have luke warm water that lost it's heat warming up the cold pipe and then you finally get hot water.

 

[badcarma]

I watch a show a while back on home repair that had the same problem , newer houses are plumed with smart faucets to keep from getting burnt in the shower when someone flushes a toilet so your faucet is probably bad.

 

[schrobsou]

Try turning the valve off at your washing machine. Most people always leave them turned on and sometimes the valve built into the washer will act as a bypass. If you had turned off the cold water supply on the water heater and you still had water coming out untill you shut the whole house down pretty much tells me that you have something creating a cross connection.

 

[ToledoEngineer]

A few thoughts. Most have already been mentioned, but it's worth noting again.


1) House is only 7 years old, but how much mineral is in your water supply? Could the pipes have build up in them yet? You are likely dealign with PVC, or copper, but if for some reason you have iron pipe, I would suspect this. With aerators, you wont lose pressure, but you will lose flow rate. Lower flow rates mean it takes longer to get the hot water through the cold pipes. Which leads into my second thought.

2) Are the pipes insulated? This is actually something I have been meaning to do to my basement pipes. Even just a 20 foot segment of pipe can lose enough temperature to feel luke warm coming from a 120 degree tank of water.

3) Check the lines going to and from the hot water tank. Check to see if any lines have somehow been crossed to the shower. If a cold water line somehow became mixed with a hot water line, then you will never have anything more than sub-luke warm water. Ground water is just too cold. This sounds like the the most obvious thing to check from your response. This happened to my grandparents about a decade ago. Had someone come in and redo the lines and they had cold water in the wrong spot up in the shower. They literally had crossed the copper pipes inside the wall without realizing it. Do not paint the water lines, but sometimes it is okay to dab a brush of red or blue on a visable section of pipe near a valve or tee. It helps years down the line when somethign breaks and you then do not have to go crisscrossing lines down the basement/crawlspace to find which is which. You can just go to the last intersection and see quickly. Another option would be to use red vs blue pex if you ever upgrade your lines.

4) Check your water heater set point. Sometimes, you have to bump it up. I dont think this is the case here, but sometimes weird things happen.

5) Check your anti-scald setting in the shower, unless this is a three knob, vs one knob. Btw, I HATE one-knob systems. There is so little control over hot water to begin with. They just exacerbate the issue by giving you 1/4 of the full turn from luke warm to burning hot. And some mixing valves only give you 90 degrees from off to full hot. Not all valves offer 270 degree turns.