Shower Only Gets Hot or Only Cold? How to Find the Cause
The handle sits in the middle, where it always gave you a warm shower, and the water comes out cold. Or it comes out hot and stays hot. Or it jumps from one to the other with nothing in between. Many single-handle tub and shower valves are pressure-balance valves, and when one of them stops mixing, the cause is often one of four things: a supply stop that is partly closed, a limit stop set too far, a balancing spool stuck with scale or debris, or a cartridge that went back in turned the wrong way.
This guide goes through each one in order, with what Moen, Delta and Kohler say to do. If the problem is only that the shower never gets quite hot enough, our guide to a shower that is not getting hot in winter covers that case in more detail.
Do not shower in water you have not tested. The U.S. Consumer Product Safety Commission says most adults will suffer third-degree burns from 150 degree water in two seconds, from 140 degree water in six seconds and from 130 degree water in thirty seconds, and it urges everyone to set the water heater to 120 degrees F. Moen, Delta and Kohler all say the water leaving a shower valve should be 120 degrees F or less. Shut the water off before you take anything apart, as every maker instruction we read says.
First, is it the shower or the whole house?
Run hot water at the bathroom sink. Moen says to verify the hot water system in the home is working first. If the sink has no hot water either, the problem is upstream of the shower, at the water heater or the pipes, and a new cartridge will not fix it. If the sink runs hot, the water heater is doing its job and the cause is at the shower valve. One thing to expect: Moen notes the water at the tub or shower may not be quite as hot, or as cold, as the water at a nearby sink. Our sister site has a plain guide to the causes when a shower will not get hot, or gets too hot, upstream of the valve included.
How a pressure-balance valve mixes the water
Hot and cold come into the valve body from opposite sides. Inside the cartridge, a balancing spool evens out the pressure of the two supplies, so a toilet flush or a washing machine does not suddenly scald you, and the handle sets the mix. A limit stop caps how far the handle can turn toward hot.
The 1988 edition of ASSE 1016, the safety standard for these valves, requires a pressure-balancing valve to cut its flow automatically when the cold supply fails, so the water leaving it does not go above 120 degrees F. Kohler lists its Rite-Temp valves to ASSE 1016. Moen says it is extremely important that both hot and cold water reach the inlets of the valve body. Delta adds that unless both hot and cold supplies are turned on, its Monitor pressure balance valve will allow only a dribble of water through. Delta and Kohler also say not to install a shut-off device on either outlet of the valve. Delta says it can defeat the balancing, and Kohler says it can create a cross-flow condition that affects the water temperature. Delta and Kohler both add that a pressure-balance valve does not correct for changes in the temperature of the supply water.
1. A stop or supply that is partly closed
Some valves have a small stop on each inlet, behind the trim, so the water can be shut off at the shower. If someone closed one for a repair and did not open it all the way again, that side runs short. Moen says that if external shut off valves are present, verify they are opened all of the way.
- Moen Posi-Temp: stop check valves are an option on these valves. Moen says the stop is open when its slot is horizontal and closed when the slot is vertical. Moen also warns: do not remove the retaining clips for the cartridge or the stop check valves.
- Delta MultiChoice 13/14 Series: on models with stops, Delta turns the stop with a flat head screwdriver, clockwise to close and counterclockwise to open, and says to leave the stops full open.
- Kohler Rite-Temp: Kohler's K-8304 valve body has service stops that include integral check valves. The K-304-K valve, which takes the GP500520 unit, is listed without screwdriver stops.
If a stop will not turn, or the valve has no stops and the house shut-off will not close fully, call a plumber. That is our own advice.
2. A limit stop set too far toward cold, or toward hot
If the shower is warm but never hot, look at the limit stop before you buy anything. Moen says to check that the handle rotates all the way counterclockwise to a 9 o'clock position. If it stops before that, the limit stop needs to be repositioned. A limit stop set too far the other way lets the water run hotter than it should, and for that case Moen says to pull the limit stop out, rotate it clockwise and set it in a lower notch.
The direction is not the same on every valve, so go by the instructions for yours:
- Delta MultiChoice 13/14 Series (RP46074): Delta says turning the rotational limit stop clockwise lowers the outlet temperature and counterclockwise raises it, and that each tooth could change it by 4 to 16 degrees F, depending on the water coming in.
- Delta Monitor 1300/1400 Series (RP19804): Delta says to mark the position of the limit stop before you take the cartridge out. Two Delta instruction sheets give opposite directions for this cartridge, so follow the sheet that comes with your cartridge and test the water with a thermometer.
- Kohler Rite-Temp: Kohler sets the maximum temperature with a collar and setscrew on the valve stem. For a small change, adjust the setscrew. For a bigger one, Kohler has you remove the O-ring and collar, slowly rotate the valve stem until a thermometer shows the temperature you want, and put the collar back. Kohler says the water temperature should never be set above 120 degrees F.
Delta says the limit stop may need resetting seasonally, as the incoming water gets colder or warmer. Delta and Kohler also say that work on the water heater changes the hottest water the valve can deliver, so check the limit stop again after any water heater change.
3. Hot or cold, nothing in between: a stuck balancing spool
When the shower snaps from cold to hot with no warm setting, or gives only one temperature wherever the handle sits, the balancing spool is the usual suspect. For its Monitor pressure balance valves, Delta answers this exact question: the spool and sleeve may not be working properly, which can be caused by mineral deposits from hard water that build up over time. Moen says the cause is debris or an obstruction in the balancing spool that keeps it from moving freely.
- Delta: with the water shut off, turn the handle to the full on, mixed position, then take the cartridge out and shake it. Delta says the test will not work if the cartridge is in the off position, that a rattle means it is functional, and that no rattle means replace it. For mineral deposits in a Monitor valve, Delta suggests soaking the cartridge in a 50/50 vinegar and water solution for 24 hours.
- Moen Posi-Temp: Moen says the 1222 cartridge needs replacing and the valve body needs to be flushed and cleaned. Moen also says that if the water pressure drops when you go from cold to hot, the 1222 needs replacing.
- Check the handle on a Moen first. Moen says that if a Posi-Temp handle is on upside down, it will not rotate the cartridge to give a mix of hot and cold, and the fix is to take the handle off and put it back on correctly.
Moen recommends cleaning and flushing the valve body whenever a new cartridge goes in, to clear mineral build-up and loose debris that could damage the new cartridge or block the flow. Moen scrubs the inside of the valve body with a nylon bristle brush, then turns the water on only slightly so a small flow goes through, one side at a time if the valve has hot and cold shutoffs. Moen warns the water may come out of the open valve body with considerable force and says to stand outside the tub or shower when the water goes back on.
4. Hot and cold swapped after a repair
If the handle turned toward hot now gives cold, the cartridge most likely went in turned the wrong way, or the supply lines are reversed behind the wall. Each maker fixes it differently:
- Moen 1222: Moen says that if the hot and cold are reversed, remove the cartridge and rotate it 180 degrees. In a normal install, the H and C tab points up.
- Delta MultiChoice 13/14 (RP46074): for back to back or reversed installs, with hot on the right and cold on the left, Delta says to insert the cartridge with the hot side on the right.
- Delta Monitor 1300/1400 (RP19804): Delta says the raised stop on the cap always goes on the hot water inlet side, so cold water flows first. In a normal install, that is the left.
- Kohler: Kohler says the cartridge in its K-8304 Rite-Temp valve body is reversible for installs where the hot and cold supplies are reversed. Follow the instructions that came with your valve.
On a Delta valve, test it the way Delta says: turn the handle on and make sure cold water flows first.
Replacing the cartridge
If the stops are open, the limit stop is set and the water still will not mix, the cartridge is next. Match the cartridge to the valve, not to the handle style. Delta is clear that these two single-handle cartridges are not interchangeable: a white cap is the RP19804 for Monitor 1300/1400 valves made before March 2006, and a grey cap is the RP46074 for MultiChoice 13/14 valves made after March 2006.
| Valve | Cartridge | What to watch | Full guide |
|---|---|---|---|
| Moen Posi-Temp single-handle | 1222 | Slide out the retainer clip, twist the cartridge with the plastic tool, clean and flush the body, then fit the new one with the H and C tab up. Moen says the water cannot go back on if the clip is not installed. | Moen 1222 replacement |
| Delta Monitor 1300/1400, white cap | RP19804 | Mark the limit stop first. The raised stop goes on the hot side. Flush the lines for one minute, then check that cold flows first. | Delta Monitor guide |
| Delta MultiChoice 13/14, grey cap | RP46074 | Do not pry it out with a screwdriver. Delta has you put the handle on and turn it counterclockwise about a quarter turn past the stop to free it. | Delta shower guide |
| Kohler Rite-Temp K-304 | GP500520 pressure balancing unit | Kohler pulls the old unit with pliers and warns not to set the new one in at an angle and rotate it, or the small O-rings move out of position and the valve leaks. | Part page |
Delta's MultiChoice manual says a light coating of plumbers grease on the O-rings may aid assembly, and Moen says to lubricate the grommets on the 1222.
When to stop and call a plumber
Each of these is our own advice, not a maker rule.
- The sink has no hot water either, or the water heater is leaking, making noise or showing an error.
- A stop on the valve will not turn, or the valve has no stops and the house shut-off will not close fully.
- The cartridge will not come out with the method the maker gives, or something breaks off inside the valve body.
- The shower still runs only hot with a new cartridge, the stops open and the limit stop set. Delta and Kohler both warn that a pressure-balance valve may not protect you from scalding if a temperature control elsewhere in the plumbing has failed.
Frequently asked questions
Why does my shower only run cold when the sink has hot water?
Then the water heater is working, and the cause is at the shower valve. Moen names debris or an obstruction in the balancing spool, and says that in some models a lack of pressure feeding the hot and cold, or a valve that needs calibrating, can be the cause. Check that any stops on the valve are fully open, then the limit stop, then the cartridge.
Is a shower that only runs hot dangerous?
It can be. The U.S. Consumer Product Safety Commission says most adults will suffer third-degree burns from 150 degree water in two seconds, and that 130 degree water takes thirty seconds. Moen, Delta and Kohler all say the water leaving the valve should be 120 degrees F or less. Our advice: turn the shower off and do not use it until the cold side works again.
Can I clean the cartridge instead of buying a new one?
For its Monitor valves, Delta says a shower that is either hot or cold with nothing between can have mineral deposits on the spool and sleeve, and suggests soaking the cartridge in a 50/50 vinegar and water solution for 24 hours. For a Moen Posi-Temp valve, Moen says to replace the 1222 cartridge and flush and clean the valve body.
Why are hot and cold backwards after I put in a new cartridge?
The cartridge may have gone in turned the wrong way, or the supply lines may be reversed. Moen says to take the 1222 out and rotate it 180 degrees. For a Delta MultiChoice valve with reversed supplies, Delta says to put the cartridge in with the hot side on the right. On a Delta RP19804, the raised stop goes on the hot inlet side. Delta also says cold water should flow first when you turn the handle on.
Do I need to reset the limit stop after a new cartridge?
Our advice: check it every time. Delta has you mark the limit stop on an RP19804 before you take it out and set the new one the same way, then test. Delta says the limit stop may need resetting with the seasons, and Delta and Kohler both say a change at the water heater means the limit stop needs checking again.
Sources
The steps above come from these pages, except where a step says the advice is our own. We opened each one on October 12, 2026.
- Moen: No cold or no hot water on tub shower units, Water temperature is not hot enough, No warm water, Adjust the PosiTemp temperature limit stop, PosiTemp stop check valves, Reverse hot and cold for a 1222 cartridge, 1222 cartridge replacement and Valve body cleaning and flushing.
- Delta: MultiChoice 13/14 Series instructions 107528, RP19804 cartridge sheet 34459, 1300/1400 and 13/14 cartridge instructions 48027, The water in the shower is either hot or cold, installing Monitor valves back to back, and the parts pages for RP19804 and RP46074.
- Kohler: Adjust the temperature on a Rite-Temp shower valve, Rite-Temp K-304 service part instructions, single-control bath and shower trim installation guide 1018257, K-304-K specification, K-8304-KSL specification and GP500520 parts page.
- ASSE 1016 (1988 edition), Performance Requirements for Individual Thermostatic, Pressure Balancing and Combination Control Valves for Bathing Facilities.
- U.S. Consumer Product Safety Commission, Avoiding Tap Water Scalds.
Replacement pressure-balance cartridges for Moen Posi-Temp, Delta Monitor and MultiChoice, Kohler Rite-Temp, Grohe, Gerber and Pfister valves, plus stems for two- and three-handle showers, shipped from Amazon fulfillment centers with Prime delivery.
See the full FourHome assortment on AmazonFourHome is an independent brand and is not affiliated with Moen, Delta, Kohler, ASSE or the other publishers cited. Brand names and part numbers are used only to identify compatibility or to cite their published instructions. Shut the water off first, test the water before you step in, and call a licensed plumber for anything beyond a cartridge swap.
FourHome is not affiliated with or endorsed by any faucet manufacturer. Brand names and part numbers are used only to identify compatibility.