I am having a problem with my shower. Sometimes the water will not get hot, only warm. Most of the time it gets plenty hot. This is starting to happen more frequently.

Hi JZ... see if you can get a name off the shower valve. That always helps us get answers quicker.

Otherwise, see if you can take a picture and post it to this site under the GO ADVANCED feature at posting space.

Get back to us... MARK

The name on the faucet says moen, but I don't think that is the problem. Mornings are usually the worst. Today I tried the water in the sink and it was the same. I cannot get the water better than lukewarm if it has been sitting for awhile. We have a gas water heater. The brand is Bradford White. Hope this helps

OK JZ

Next time you post tell me what size the water heater is and how old it is.

Unfortunately, there are a few different things that could be the culprit.

The dip tube
The gas valve
The burner assembly

You need to do a few tests to determine which one... ok?

Start with least invasive to the system... the gas valve/thermostat and the system recovery.

First, I want you to check the thermostat.. see what it is set on... may be as simple as someone brushing by the heater and moving the thermostat. The knob should be set between warm and hot at the raised nub on handle (or slightly hotter).

Second, time how long a shower lasts before you start to see the drop in temperature. If the temperature is dropped before even taking the shower then I think it may be your dip tube... see picture. Dip tube is in cold water side tapping of the heater.

If the dip tube is defective or was improperly installed (again.. I don't know how old here) it will present almost exactly as you have presented your situation (still check the thermostat setting).

Dip Tube removal

Turn the gas valve/thermostat setting to vacation.

Shut off cold water shutoff into the heater. Then open your 2 HANDLE FAUCETS (if any) HOT water handles ONLY and/or drain off 5 gallons at the heater drain itself. Then will need to cut the cold water pipe below the cold water shutoff, but above the cold water heater nipple, then back off the nipple (with pipe/fitting still attached if possible) with wrench and reach in with your finger and pull out the dip tube (long white plastic tube)... inspect that. It may be cracked, may look melted. It may have even broken off or partially broken off and fallen to heater bottom... let us know. Then would need to replace the dip tube (a plumbing supply house has these in stock). Purchase a dip tube and a coupling the same size as the pipe you cut.

Then teflon tape the nipple (6/7 wraps clockwise) and install the nipple onto heater. Then sandpaper clean the two cut ends of pipe and the coupling and then flux all, then install coupling and then solder it (lead free solder, please). Then turn water back on, purge air from the lines (I purge to the tub or a laundry sink FIRST!. then purge the smaller faucets). Then turn gas valve/thermostat setting back to were it was (about 120 degrees or so... between hot and warm at the raised nub.. or slightly higher).

If you need information on soldering there are some great videos out there in the internet world to watch OR just come back here and we can walk you through.. ok?

You may also want to drain/power flush the water heater, where you hook hose to drain at heater and leaving water ON to heater, open the drain and flush any sediment at bottom of tank out of tank for 5/10 minutes... then that heater should be good to go for awhile longer.

Anyway... that is a start for you... evaluate this and then get back to me... especially size of heater and how long it keeps hot. I think it is the dip tube (obviously ;) )