Your steam generator is the most important component of your steam shower — and mineral scale buildup is the leading cause of steam generator failure. Every time the generator heats water, dissolved minerals are left behind as the water turns to steam. Over time that buildup reduces efficiency, degrades performance, and shortens the life of the unit. Mr. Steam AutoFlush is the solution: an automatic self-cleaning system that flushes your generator of sediment and old water two hours after every steam session, with no buttons to push and nothing to remember.
TheSteamStore.com is an authorized Mr. Steam dealer. Shop MS AutoFlush and MX AutoFlush at TheSteamStore.com, or contact our team with questions about compatibility for your generator.
Why scale buildup is a serious problem
When water is heated to boiling point inside a steam generator, dissolved minerals — primarily calcium and magnesium — do not evaporate with the water. They stay behind and deposit as scale on the heating elements and the interior walls of the tank. In hard water areas this process happens quickly. In moderate water areas it happens more slowly — but it always happens.
Scale buildup causes two problems. First, it acts as an insulator on the heating elements, forcing them to work harder and longer to heat the same amount of water — reducing efficiency and increasing energy consumption. Second, it accumulates over time into hard deposits that can crack heating elements, clog outlet ports, and ultimately cause the generator to fail. Scale is the single most common cause of premature steam generator failure across all brands.
The standard recommendation for any steam generator without an automatic flush system is annual manual descaling — draining the tank, flushing with a descaling solution, and refilling. This works, but it requires remembering to do it, scheduling the work, and actually following through year after year. Most homeowners do not. AutoFlush makes the maintenance question irrelevant by handling it automatically after every single session.
How AutoFlush works
AutoFlush is a Mr. Steam exclusive product — no other steam brand offers an equivalent system. It works through a simple, reliable process that runs entirely in the background:
- You finish your steam session and turn off the generator as normal
- Two hours later, after the generator has cooled, AutoFlush automatically activates
- An electronically-activated valve opens and the generator drains by gravity — flushing old water and accumulated sediment out through the drain line
- Fresh water refills the tank, ready for the next session
- Nothing to push, nothing to remember — the entire process happens automatically every time
The two-hour delay is intentional — it gives the generator time to cool before flushing, which protects the system and ensures the flush is safe and effective. If the Mr. Steam Express Steam option is installed, AutoFlush works slightly differently: it drains for ten minutes then refills with fresh water to begin the pre-heat cycle, so your generator is always primed and ready.
The result: Clean steam every time. By flushing sediment-laden water out of the generator after every session and replacing it with fresh water, AutoFlush ensures the generator is always starting from a clean state. The heating elements stay clear, efficiency stays consistent, and the generator lasts significantly longer than it would without automated maintenance.
MS AutoFlush vs. MX AutoFlush — which do you need?
AutoFlush is available in two versions depending on your Mr. Steam generator series:
| MS AutoFlush | MX AutoFlush | |
|---|---|---|
| Compatible with | Mr. Steam MS Series generators | Mr. Steam MX Series generators |
| Drain method | Gravity drain via electronic valve | Gravity drain via electronic valve |
| Connection | Three pin connector — see installation manual for nipple size | Three pin connector — see installation manual for nipple size |
| Box contents | AutoFlush valve with cord, installation instructions | AutoFlush valve with cord, installation instructions |
| Flush timing | Two hours after every session — all models | |
Not sure which version you need? Contact our team with your generator model number and we will confirm the correct AutoFlush version before you order.
Installation requirements
AutoFlush installation must be performed by a qualified plumber in accordance with applicable national and local codes. Before ordering, confirm the following at the generator location:
- Drain line availability — the generator drains by gravity, so a drain line that is lower than the AutoFlush assembly must be available. The drain cannot run uphill
- Drain location — do not drain into the steam enclosure or any location where accidental contact with drain water may occur. In the event of a power failure the AutoFlush valve will open and may discharge hot water
- Copper or brass nipple — required to connect the AutoFlush valve to the drain valve but not supplied. See the installation manual included with your unit for the correct size
- Drain valve — the existing drain valve on the generator must remain in place and must never be removed or turned. Removal may cause equipment and property damage
- Electrical connection — the AutoFlush cord connects to a three-pin connector on the generator. No separate electrical circuit is required
AutoFlush can be installed on new generators at rough-in or added to existing installations. For older Mr. Steam generators (serial number 899,999 and below), a slightly different wiring procedure applies — contact MrSteam Technical Service at 800-767-8326 (East Coast) or 800-727-8326 (West Coast) for guidance on older model installations.
Do I need AutoFlush?
AutoFlush is recommended for all Mr. Steam generator installations — but it is particularly important in these situations:
- Hard water areas — if your water hardness is above 7 grains per gallon, scale buildup is an active concern. AutoFlush is essentially mandatory in hard water regions for long-term generator health
- Frequent users — the more sessions per week, the more scale is deposited. Daily steam users especially benefit from AutoFlush's after-every-session flushing
- Anyone who does not want to think about maintenance — AutoFlush removes the annual descaling requirement entirely. Install and forget
- Premium installations — if you have invested in a high-end steam shower, protecting the generator with AutoFlush is the logical extension of that investment
AutoFlush vs. manual descaling
| Mr. Steam AutoFlush | Manual descaling | |
|---|---|---|
| Frequency | After every session automatically | Once per year recommended |
| Effort required | None — fully automatic | Manual drain, flush, refill process |
| Scale prevention | Proactive — flushes before scale hardens | Reactive — removes scale after it has built up |
| Relies on homeowner | No | Yes — easy to forget or skip |
| Drain method | Gravity drain via electronic valve | Manual drain |
| Result | Clean steam every session, extended generator life | Variable — depends on how consistently it is done |
Frequently asked questions
Does AutoFlush work with all Mr. Steam generators?
AutoFlush is available in two versions — MS AutoFlush for MS Series generators and MX AutoFlush for MX Series generators. Confirm your generator series before ordering. Contact our team with your model number and we will confirm which version you need.
When exactly does AutoFlush activate?
AutoFlush activates approximately two hours after every steam session ends. The delay allows the generator to cool before flushing, resulting in a safe and gentle operation. If Express Steam is installed, AutoFlush drains for ten minutes then refills with fresh water to begin the pre-heat cycle.
Does AutoFlush require a drain near the generator?
Yes — AutoFlush drains by gravity, so a drain line that is lower than the AutoFlush assembly must be available at the installation location. This should be planned at rough-in on new installations. Do not drain into the steam enclosure.
Can AutoFlush be added to an existing Mr. Steam generator?
Yes — AutoFlush can be added to an existing installation as long as a gravity drain is accessible near the generator. For older generators (serial number 899,999 and below), a slightly different wiring procedure applies. A qualified plumber must perform the installation per local codes.
What happens to AutoFlush during a power failure?
In the event of a power failure the AutoFlush valve will open and may discharge hot water. This is why the drain must never route into the steam enclosure or any location where accidental contact with drain water could occur.
Is AutoFlush loud?
No — the system drains by gravity through an electronically-activated valve and operates quietly. The flush cycle runs in the background two hours after your session.
Does AutoFlush eliminate all maintenance?
AutoFlush significantly reduces maintenance requirements by preventing scale buildup after every session. Periodic inspection of the generator and AutoFlush system is still recommended. In very hard water areas, a water softener upstream of the generator will further extend its life in addition to AutoFlush.
See AutoFlush in action
Add AutoFlush to your Mr. Steam system
Shop MS AutoFlush and MX AutoFlush at TheSteamStore.com, or contact our team and call 877-881-5501 Monday through Friday to confirm the right version for your generator.