Rheem 21V50-2 50-gallon power miser v gas water heater Parts

Some water heater parts are interchangeable, but only when the fuel type, venting style, and control system match. For the Rheem 21V50-2 50-gallon gas water heater, always match parts by model and rating; natural gas and LP (propane) parts are not interchangeable.

Many components look similar across brands and models, but small differences in gas type, thread size, and temperature ratings can make a “close match” unsafe or unreliable.

• Often interchangeable (when specs match): drain valves, some anode rods, some dip tubes
• Sometimes interchangeable: thermocouples (length and connection style must match)
• Not interchangeable: gas control valves, burner/orifice parts, pilot assemblies (especially between natural gas and LP)
• Model-specific fit matters: access panels and doors can be shape-specific

Use this checklist to confirm you are buying the right replacement part for a Rheem gas water heater like model 21V50-2:

• Confirm fuel type (natural gas vs LP/propane)
• Match the model number: 21V50-2 on the rating plate
• Compare connection type and size (NPT thread size, compression fittings)
• Match part length when applicable (dip tube, thermocouple)
• Verify temperature and pressure ratings for water-contact parts

Interchanging the wrong gas or control parts can cause ignition problems, poor combustion, or unsafe operation. Even “simple” plumbing parts can leak if thread type or rating is wrong, so matching by model and specifications prevents repeat repairs.

Last updated: February 2026

Yes, you can install the Rheem 21V50-2 50-gallon power miser v gas water heater yourself if you already have solid plumbing and gas-venting experience and you can meet local code requirements. For many homes, a licensed installer is the safest path because gas piping, combustion air, venting, and leak testing must be done correctly.

A gas water heater install is more than swapping tanks; it is a full safety and code-critical setup.

• Shut off gas and water; drain and disconnect the old tank
• Set the new heater level, with proper clearances and a stable base
• Connect cold and hot water lines (often with dielectric unions or approved connectors)
• Install the temperature and pressure relief (TPR) valve and a discharge pipe to an approved location
• Connect the gas supply with an approved shutoff valve, sediment trap (drip leg), and leak test
• Verify venting type, vent slope, draft, and combustion air supply
• Fill the tank completely and purge air before lighting

If any of the items below apply, we recommend professional installation.

These are common service parts on this model that are often handled during draining, maintenance, or reassembly.

• Drain valve 100108605 (used for draining the tank for replacement or sediment flushing)
• Dip tube SP11248R (helps deliver incoming cold water to the bottom of the tank)

A correct install protects your home from gas leaks, venting problems, scalding risk, and water damage. It also helps the Rheem 21V50-2 heat efficiently and reduces nuisance pilot outages and sediment-related issues.

Last updated: February 2026

A 50-gallon gas water heater like the Rheem 21V50-2 typically costs about $500 to $1,200 for the unit alone. Total replacement cost is usually higher because professional installation, venting, gas-line work, and code-required updates can add roughly $600 to $2,500.

• Venting changes (draft hood, vent connector, chimney or power-vent setup)
• Gas line updates (sediment trap, shutoff valve, pipe sizing)
• Water piping condition (corroded nipples, old shutoffs, galvanized pipe)
• Local permit and inspection requirements
• Warranty length and efficiency level (higher efficiency usually costs more)

• Confirm the exact model number on the rating plate; use our guide: how to find your appliance model number (and what it means for parts).
• Match fuel type (natural gas vs. LP) and venting style to your current setup.
• Measure available space; most 50-gallon tanks are roughly 20 to 24 inches in diameter and 55 to 65 inches tall.
• Plan for maintenance parts that commonly get replaced over time, such as a leaking drain valve 100108605 or a worn dip tube.

A water heater price quote is really a combination of the tank plus the work needed to keep the installation safe and code-compliant. Getting the right venting and gas connections prevents nuisance shutdowns, poor performance, and premature part wear.

Last updated: February 2026

Most 50-gallon tank-style water heaters, including the Rheem 21V50-2 50-gallon power miser v gas water heater, typically last 8 to 12 years under normal water quality and maintenance. Regular flushing and timely part replacement help you stay closer to the high end of that range.

• Hard water and heavy sediment buildup in the tank
• Running very high temperature settings year-round
• Corrosion from a depleted anode rod (common failure driver)
• Frequent pilot outages or burner issues (gas models)
• Slow leaks at fittings, the drain valve, or the tank itself

• Flush a few gallons from the tank periodically to reduce sediment
• Test the temperature and pressure relief valve periodically
• Inspect for moisture around the base and plumbing connections
• Replace worn service parts promptly, such as the drain valve 100108605 if it seeps or will not close
• If you get sudden “lukewarm” water, inspect hot-water delivery components such as the dip tube SP11248R

Knowing the typical 8 to 12 year lifespan helps you plan: if your Rheem 21V50-2 is already in that age range and you are seeing rust-colored water, recurring pilot problems, or tank sweating that turns into puddling, it is time to evaluate repair versus replacement.

Last updated: February 2026

The most common problem we see on gas water heaters, including Rheem model 21V50-2, is pilot ignition failure (pilot will not stay lit or burner will not stay on). A close second is sediment buildup in the tank, which causes rumbling, slow recovery, and reduced hot water.

• Pilot will not stay lit: thermocouple circuit issue, dirty pilot, or gas control problem
• No hot water but pilot is on: thermostat or gas control valve issue
• Rumbling or popping sounds: heavy sediment in the tank
• Slow hot water recovery: sediment, restricted burner air, or gas supply issue
• Water around the heater: leaking fittings, drain valve seepage, or tank failure

These parts from the 21V50-2 parts list often come up during diagnosis:

• Confirm the gas shutoff valve is fully open.
• Make sure the venting and combustion air area is clear (no lint, dust, or blockage).
• After a hot water draw, listen for burner ignition; no ignition points to the pilot/safety circuit.
• If you hear rumbling, schedule a tank flush to reduce sediment.
• If you see moisture, check the drain outlet and nearby fittings before assuming the tank is leaking.

A gas water heater is designed to shut the burner off if it cannot prove a safe flame, so a small ignition-safety issue can look like a “dead” heater. Sediment buildup wastes fuel and reduces usable hot water.

Last updated: February 2026

On a Rheem gas water heater like model 21V50-2, the model number is printed on the rating plate (data label) attached to the outside jacket of the tank. You will usually find it on the side of the tank near the burner access area or near the gas control.

Check these spots in order; the label is typically easy to see without removing major parts:

• Side of the tank near the gas control valve/thermostat area
• Side of the tank near the burner access opening
• Upper side of the tank near the flue draft hood area
• Around the perimeter of the jacket where warning labels are placed
• A second label on the opposite side of the tank (if the first is damaged)

Write the information exactly as shown so we can match the correct Rheem parts list.

• Wipe gently with a damp cloth; avoid solvents that can remove printing.
• Take a phone photo and zoom in; side lighting makes faint text readable.
• If the label is missing, look for any secondary sticker near the gas control or on the opposite side.

The model number is the fastest way to match the right replacement parts for your Rheem 21V50-2, such as a drain valve 100108605 or dip tube SP11248R, and avoid ordering a part for a different tank series.

Last updated: February 2026