The Caleffi 6686L5S1A is a TwistFlow 668S1-series pre-assembled radiant distribution manifold with 10 loops and a 1 in NPT female trunk, pairing a brass supply manifold with per-loop sight flow gauges and balancing valves with a brass return manifold with individual shut-off valves, for precise circuit-by-circuit control of radiant floor and panel systems.
Product data compiled from Caleffi North America technical documentation (01170 NA, 01155 NA). Last reviewed July 2026.
Key Features
Complete Pre-Assembled Set
Brass supply manifold with flow meters and balancing valves, brass return manifold with shut-off valves, isolation ball valves and mounting brackets - assembled and ready to hang.
Sight Flow Gauges, 1/4 - 2 gpm
Each loop has a visible PSU sight gauge with balancing valve (accuracy +/-15%), so per-circuit flow is set and verified without instruments.
10 Loops on 2 in Centers
10 radiant circuits with 3/4 in male outlets on 2 in center distance, ready for PEX adapter fittings.
TwistFlow Balancing Design
Twist the regulating cover to dial the loop flow; internal stainless springs and peroxide-cured EPDM seals keep settings stable.
Built-In Air Management
Automatic air vent valves (brass stem, PP float) and end fittings purge air continuously; max end-fitting discharge 35 psi.
Glycol-Ready Brass Construction
Brass manifold bodies rated 150 psi and 32 - 180 F, for water and glycol solutions up to 50%.
Technical Data
| Function | Pre-assembled radiant distribution manifold (668S1 series) |
|---|---|
| Number of outlets | 10 ports, 3/4 in male, 2 in center distance |
| Main connections | 1 in NPT female |
| Manifold body | Brass (supply and return) |
| Flow meter | PSU sight gauge, 1/4 - 2 gpm, accuracy +/-15% |
| Seals | Peroxide-cured EPDM; stainless steel springs |
| Air vent | Automatic, brass stem, PP float; max discharge 35 psi |
| Suitable fluids | Water, glycol solutions (max 50%) |
| Maximum operating pressure | 150 psi |
| Medium temperature range | 32-180 °F |
| Flow meter scale | 1/4-2 gpm |
| Outlet center distance | 2 in |
Documentation
Technical brochureRelated Products
Frequently Asked Questions
A pre-assembled set: brass supply manifold with 10 sight flow gauges and balancing valves, brass return manifold with 10 shut-off valves, isolation ball valves, automatic air vents, end fittings and mounting brackets.
Twist the regulating cover on each outlet while reading the built-in sight gauge (1/4 - 2 gpm); no separate flow instruments are needed.
The 3/4 in male outlets on 2 in centers accept standard Caleffi PEX adapter fittings for PEX or PEX-AL-PEX radiant tubing.
Yes - water and glycol solutions up to 50%, rated 150 psi and 32 - 180 F.
Each manifold includes automatic air vent valves that continuously purge air from the circuits (max discharge pressure 35 psi).
- Type:
- Radiant Manifold
- Number of Ports:
- 10
- Series:
- TwistFlow
- Connection Size:
- 1 in
- Configuration:
- Standard