I'm getting hot water for 2 minutes , then it gets cold

There is an adjustment knob to control how hot the water can become. There might be a problem at the tap (however, if this is the case, you would still get hot water everywhere in the house). If the entire house isn't getting hot water, and the knob is set at the hottest water, you probably need to get the hot water tank replaced.

You probably need new a new cearamic insert (or two), but I can't point you at where to get it because I don't know where you are. Franke FR2 014 Cold Valve Seat For LB2200 Lil Butler 2 014 also known... Franke FR2 015 Hot Valve Seat For LB2200 Little Butler 2 015 also known...

It sounds like your thermostat on the water heater isn't working properly. try turning it up higher and if this doesn't work I would have a service techy look at it.

Hi,
The dip tube on the cold water side either is not there or it is broken off then the cold water stays on the top and gives cold water quickly...

If this is a new installation then check that the piping is correct and that the cold and hot pipes are not switched...

heatman101

The inlet line to the water heater goes to the bottom of the water heater to prevent the cold incoming water from mixing with the heated water at the top. The tube going to the bottom can come loose.

Turn the water off and relieve the pressure by opening a faucet and remove the fitting where the water enters the heater. You can see if the pipe is still connected.

3 minutes?? does the water run cold then? or just warm?
Is this what the tank you replaced was doing? If so, then you may have: 1 a recirculating pump instant hot water system thats faulty and allowing cold water backflow into hot water piping. 2 A tempering valve that has stuck, allowing cold water into your hot water system.
Or maybe a broken or missing dip tube in your new heater.
If after 3 minutes the water is coming cold out leave that faucet running and go to heater and feel the hot water outlet pipe from the heater. if that pipe is hot then the heater is not the problem. If the hot pipe from the heater is cold the heater is the problem. (Make sure the cold pipe coming into the heater is connected to the Right side marked "cold" !) If there is a tempering valve by the heater: feel the output from the tempering valve, if it is cold and the pipe from the heater to the tempering valve is hot, then the tempering valve is the problem. If all these are OK somewhere in your plumbing system hot and cold may be connected possibly a faucet or showerhead that is shut off at the spout/head, but hot/cold handles are left turned on then cold water can backflow thru hot pipe.

hi do you have 3/4 inch cas line running to it? if you only have 1/2 inch it is too small and running out of gas and shutting down. ed

check diaphrapm valve or micro/switch best of luck

check the screen on the cold water intake on the cold side,, you might have to flush the system out, and do you have the shower head water restricter in, if not you may be using to much hot water,,, how many other hot water fixtures are running at the same time? try running just the shower,,,if this is a tank water heater the dip tube could be bad that is on the cold side it takes the cold water to the bottom of the tank and forces the hot water out,, if you ar only getting a couple of min of hot water and the dip tube is bad it is not going to the bottom but just at the top and not getting all the hot water you will need a plumber

I wonder if you have this problem below caused by a drop in water pressure from someone flushing a toilet or a washing machine. I would call the company to remedy this issue.

17. What is a cold water sandwich effect? The term “cold water sandwich effect” is a term that is used to describe the introduction of cold water into the hot water supply line during frequent on/off operation of an instantaneous water heater. The cold water sandwich effect, when present, appears as a momentary drop in hot water temperature as it is discharged from a hot water supply outlet (i.e. shower, tub, or faucet). This phenomenon is present in the operation of all instantaneous, tankless style, water heaters, but is minimized with the high tech design of Rinnai water heaters.
The technology built into the Rinnai water heaters is designed to minimize the cold water sandwich effect. Rinnai water heaters are microprocessor controlled and when water flow through them ceases, they remain in a “ready to fire state” for approximately 1 minute. If water flow through a Rinnai water heater begins within the first minute following water flow stoppage, the water heater will fire back up within 1 to 2 seconds. This minimizes the cold water sandwich effect that would otherwise be experienced with a low tech tankless water heater. It should be noted that the cold water sandwich effect cannot be removed completely from tankless style water heaters. The safety standards developed to insure the safe operation of water heaters require a delay in the ignition sequence of all gas water heaters.
While the cold water sandwich effect cannot be completely eliminated from standard plumbing systems, it can be eliminated from plumbing systems that have a supply and return hot water circulating system. Rinnai has developed 2 methods to eliminate the cold water sandwich effect in residential hot water circulating systems.
The first (and preferred) method to remove the cold water sandwich from circulating systems utilizes a small electric tank water heater (powered up) that is used with a dual purpose. The small water heater acts as a mixing tank to eliminate the cold water sandwich effect from the Rinnai water heater and it uses its electric heating element to offset the heat losses from the hot water circulating system.
The second method to remove the cold water sandwich from circulating systems utilizes a small 2 to 6 gallon storage tank installed on the hot water outlet of the Rinnai water heater. This tank acts as a mixing tank to blend the cold water sandwich with hot water and eliminating its effect at fixtures.