No hot water?

[Amaroq]

I need advice as to what to do. Please, can anyone help? I'm desperate!

Here's the facts/events of the situation.
My water heater was old, but I've always had hot water. My water heater died last month. I purchased a new one through a store that installs. The guy came and replaced the water heater. The water would get luke-warm at best. We called the store and they sent the guy back. He claims that the water heater is running correctly. He also claims that the problem is that cold water is mixing with the hot after it leaves the heater. I still have luke-warm water at best.
(in case it's relevant, none of the faucets are two-knobbed and just yesterday I discovered that I get hotter water while the toilet is running but not when cold water is running in the sinks or shower)

My questions are:
1-Why is it my old water heater didn't have this problem and the new one does? After all, the guy just switched water heaters.
2-What do I do now? I can't handle cool showers in winter. Brrrrrr!

 

[Mr_David]

Some single handle fixtures have been known to mix /cross flow between hot/cold even while closed.

Here is how you can check for cross over. You have to have a good working valve on water heater. turn off cold supply valve to water heater.
Open a faucet to hot only. You should have Zero flow from the hot side of any fixture. If you have water flowing from a fixture with it turned to hot only then you have a cross over problem.
With the faucet still open to hot only go, listen to all other fixture (Closed).
Can you hear water flowing through any of them ??

 

[Amaroq]

I have tied that recently. The water stops after whatever is left in the pipes comes out.

 

[Mr_David]

The guy who put it in probably does not have a clue.
Run hot water some where and grab hold of the hot supply line coming out of the heater. should be the left side. cold side should have a valve on it. make sure the thing was not hooked up back wards. Take a picture of it if you can. What is the make and model?
do you have a gate valve(round handle) or a ball valve (lever) on cold supply to heater?

You turned off the cold supply to water heater. Open a faucet on hot side only water stops flowing. do you have good hot water any where else in the house?
That is with the cold supply to heater turned back on.
maybe it's the shower valve cartridge. Moen Positemps balance spools get stuck sometimes.

 

[frodo]

Mr David is correct in his assumption of a shower valve.

now, the WHY ?

when your plumber filled the heater, he did not open all the valves and let the lines purge of the air as the heater filled up.

he left the shower valve closed. air pushed JUNK that was in the line to the valve.

when you opened the valve the JUNK embedded itself in the washers and cartridges

the valve must be disassembled and cleaned of debree. or replace cartridges

 

[Amaroq]

I got a local plumber to check out the problem. He discovered the problem with the water mixing was anti-sweating mixing valves on the toilets that were both malfunctioning and bleeding cold water through the hot water lines.

The reason the problem started when the heater was changed was that the old heater was BIG and was able to compensate for the cold water mixing in with the hot. The new heater is about a third the size of the old one and couldn't cope as well. Leading to the luke-warm water.

I want to thank all of you soo much for trying to help me get hot water. This was just a fix that I could not do myself, even with great help from you guys. I'm so happy to have hot water again.

 

[KULTULZ]

I got a local plumber to check out the problem. He discovered the problem with the water mixing was anti-sweating mixing valves on the toilets that were both malfunctioning and bleeding cold water through the hot water lines.

The reason the problem started when the heater was changed was that the old heater was BIG and was able to compensate for the cold water mixing in with the hot. The new heater is about a third the size of the old one and couldn't cope as well. Leading to the luke-warm water.

I want to thank all of you soo much for trying to help me get hot water. This was just a fix that I could not do myself, even with great help from you guys. I'm so happy to have hot water again.

THANK YOU for getting back and telling us what you found!

My newly learned factoid of the day...