Mixing Valve Types, Brands and Applications
Most mixing valves can be categorized into (2) main categories - plumbing (anti-scald) and heating types.
Mixing valves used in plumbing applications, in turn, are divided into whole-house and point-of-use types. The former is generally installed near the water heater and limits the hot water temperature for the whole house (or a series of fixtures supplied by given water heater) to prevent scalding (getting burned by hot water). Point-of-use valves are intended mainly for commercial applications where they are installed to service one particular fixture (bathroom sink, shower, etc.).
All mixing valves used for domestic and anti-scald applications must comply with ASSE 1017, while point-of-use must also comply with ASSE 1070. If used for drinking water purposes, these valves must also meet the ANSI/NSF 61 & 372 (nsf-pw-g) criteria for low lead content in order to comply with 2014 SDWA.
Mixing valves used strictly in hydronic & radiant heating (non-potable water) applications do not require ASSE or NSF approvals since they do not come in contact with potable water.
Mixing Valve Comparison
| Taco series | Honeywell series |
|---|
| 5000 | 5100 | AM-1 | AM-1 “C” | AM-1 “C1070” | AM-1 “R” |
| Application | Anti-scald, hydronic heating | Anti-scald (point-of-use) | Anti-scald, hydronic heating | Anti-scald | Anti-scald (point-of-use) | Hydronic heating only |
| Lead-Free | Yes | Yes | Yes | Yes | Yes | No |
| ASSE Approvals | 1017 | 1017, 1070 | 1017 | 1017 | 1017, 1070 | - |
| Output range °F | 85-175°F | 85-120°F | 70-145°F | 70-120°F | 70-120°F | 70-180°F |
| Connections | Union Sweat, Union Threaded | Threaded, Union Sweat, Union Threaded |
Thermostatic Mixing Valves
Thermostatic mixing valve is a general term used to describe a 3-way valve which provides a constant (user pre-set) temperature water by mixing hot and cold water together proportionally. Each mixing valve model has its own ranges of incoming (both hot and cold) and output temperature and can be intended for specific uses. This valve normally has a lockable dial knob which allows user to select and "lock-in" the desired mixing output temperature. This temperature is usually below 120°F for anti-scald applications, around 140°F for radiant heating and can go up to 180°F for hydronic (baseboard/radiator) heating applications.
In potable water and anti-scald applications, thermostatic mixing valve protects the homeowner against burns while maintaining a relatively high temperature inside the hot water heater or storage tank to prevent growth of Legionella.
In hydronic radiant heating, the valve is used to maintain a desired water temperature inside the PEX circuits for optimal energy efficiency and heat distribution.
Anti-Scald Valves
The purpose of an anti-scald valve is to prevent hot water burns caused by fluctuations in hot or cold water pressure. Each year, thousands of scald cases are reported, with prevailing majority occurring in home. When water temperature at the plumbing fixture (such as a tub, shower or sink) suddenly changes, the user is subjected to thermal shock, instinctively trying to move away from the water source. Slow or lack of reaction could cause severe burns, while quick reactions present the risk of slips and falls.
An anti-scald valve, properly installed at the hot water source (hot water heater or a faucet), detects sudden changes in outlet water temperature and immediately shuts of the water if the temperature exceeds 120°F, protecting the user.
Taco Mixing Valves
Taco 5000 series valves are ASSE 1017 approved thermostatic mixing valves which can be used both as anti-scald valves and mixing valves for hydronic & radiant floor heat heating applications. 5000 series has a 175°F outlet temperature limit and allows for up to 20GPM flow.
Taco 5100 series valves are dual ASSE 1017 and 1070 approved mixing valves designed exclusively for scald protection purposes. These valves are approved for both residential and commercial settings, have a 120°F limit and allow for up to 14GPM flow.
Both series are “low-lead” compliant and are approved for potable water use.
Honeywell Mixing Valves
Honeywell AM-1 series thermostatic mixing valves include both standard (ASSE 1017) and ASSE 1070 models (the latter designated with a letter "C" in a part#) and have various, model-specific outlet temperature ratings. These valves are suitable for both residential (whole-house) and commercial (point-of-use) applications and meet the 2014 SDWA “low-lead” criteria.
Note: AM-1 "R" series valves (models with letter "R" in part#) are intended for use in heating applications only and cannot be used as anti-scald valves or for drinking water purposes.
