Vent, Valve & Volt
Shower won't get hot, or gets too hot

You can fix this

Likely cause: a stop that was not fully reopened

Many shower valves have built-in stops for hot and cold. If one was not fully reopened after a repair, the shower runs short on that side.

Why this happens

One of the first checks in Moen's guidance for a shower that will not get hot is whether the external shut-off valves are fully open. These stops are closed during a cartridge swap, and a hot-side stop left partly closed starves the valve of hot water. The main shutoff and any valve on the water heater line matter too.

How to fix it

  1. Remove the handle and trim and look for two small screwdriver-slot or hex stops on either side of the valve body. Some valves have none.
  2. Open each stop fully, following your valve's instructions.
  3. Check the house main shutoff and any shutoff on the water heater's lines are fully open. Home Depot notes a ball valve is open when the handle lines up with the pipe.
  4. Reassemble and test at full hot with a thermometer.

When to stop. If a stop will not turn, do not force it. Berkeys advises calling a plumber about a seized valve.

If this does not fix it, tell the plumber

  • The problem started right after a repair or a water shutoff.
  • Whether the valve has its own stops and whether they are fully open.
  • Whether the main shutoff was closed recently.

Build the full list: what to tell the plumber.

Start this troubleshooter over

References (every fact above comes from one of these pages)
  1. Moen: Water temperature is not hot enough on tub and shower units
  2. Home Depot: How to turn off the water to your house
  3. Berkeys: Is it a mistake to think the plumber will handle all the prep?

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