Short definition
A scald-control faucet is a single-handle tub or shower faucet with a built-in pressure-balance spool, a thermostatic cartridge, or both — preventing the user from being scalded if cold-side pressure drops or hot-side temperature spikes. It’s the homeowner-friendly name for an ASSE 1016 valve, which UPC 408.3 requires on every shower and tub-shower in WA.
What it is
This is the same device covered in the anti-scald-valve entry from the regulatory side — different name, same fixture. Three flavors satisfy the code:
- Pressure-balance only. Cheapest. Spool senses pressure differential and throttles hot when cold drops. Standard residential.
- Thermostatic only. A wax cartridge senses absolute temperature and holds setpoint regardless of pressure changes. More accurate, more expensive.
- Combination pressure-balance + thermostatic. Both protections. Higher-end residential and commercial.
Maximum showerhead output is 120 degrees Fahrenheit. The high-temperature limit stop — a small notched ring inside the trim — enforces that cap and must be set after every cartridge replacement.
Why it matters to a homeowner
If you have a single-handle tub/shower built or remodeled in the last twenty-plus years, you have a scald-control faucet. If you have a pre-1990 three-handle setup (separate hot, cold, and diverter), you don’t — and any remodel that touches the valve will trigger the code-required upgrade. Pre-purchase inspectors flag missing scald protection in older WA homes routinely.
Symptoms when it fails: shower runs hot when someone flushes a toilet, output drifts cold-only or hot-only, or a temperature surge that should be impossible happens anyway. The cure is usually a cartridge replacement (Moen 1222 or 1225 for Moen valves, Delta RP46074 or RP19804 for Delta) — $25 to $60 in parts, honest DIY for someone comfortable shutting off water and pulling a handle.
When a contractor’s quote says “ASSE 1016 valve” or “pressure-balance shower valve,” that’s this part.
Common failure modes
- Pressure-balance spool stuck. Temperature surges when other fixtures use cold.
- Thermostatic wax cartridge fails. Output stuck cold or hot regardless of handle.
- High-limit stop not set. Output exceeds 120 degrees because nobody set the limit after a cartridge swap.
Common variants
- “Scald-control faucet” (homeowner language) ≈ “anti-scald valve” (regulatory) ≈ “pressure-balance valve” (mechanism). Same device.
- ASSE 1016 (point of use, shower) vs. ASSE 1017 (water-heater outlet) vs. ASSE 1070 (point of use, sinks/lavs/tubs without thermal-shock protection).