7.3 Water Heaters, Water Treatment Devices & Other Plumbing Appliances
Key Takeaways
Water heaters must be listed by an ANSI-accredited third party under the Table 384.20-1m standard for their type, have a drain valve of at least 3/4 inch with a male hose-thread outlet, and stay accessible.
A dual-use (potable and space heating) system heating water above 125 degrees F needs an ASSE 1017 mixing valve limiting potable hot water to 125 degrees F or less.
Instantaneous water heaters for one- and 2-family dwellings must deliver an initial temperature of 125 degrees F or less.
Water treatment devices must meet a Table 384.20-2 standard (for example NSF/ANSI 44 for residential softeners and 58 for reverse osmosis), and injected compounds must be listed drinking water additives.
Residential food waste grinders meet ASSE 1008 and need at least a 1-1/2 inch drain; commercial dishwashers meet ASSE 1004; emergency fixtures meet ANSI/ISEA Z358.1.
Why appliance standards are tested
The journeyman exam includes "materials and products" items. Most come from two places: the product standard an appliance must meet (SPS 384.20 (5)), and the installation rule in SPS 382 for that appliance. Learn them as pairs.
Water heaters (SPS 384.20 (5) (p))
| Requirement | Detail |
|---|---|
| Listing | Tested and listed by a nationally recognized, ANSI-accredited third party under the Table 384.20-1m standard for the type |
| Dual-use systems | If space heating needs water above 125 degrees F, an ASSE 1017 thermostatic mixing valve limits the initial potable hot water to 125 degrees F or less |
| Drain valve | At least 3/4 inch NPS with a male garden-hose-thread outlet at the lowest point of each heater and hot water storage tank |
| Access | Accessible for inspection, service, maintenance and replacement |
| Labels | Indelibly labeled per the applicable standard; residential heaters and tanks show the maximum working pressure visibly after installation |
| Instantaneous heaters for one- and 2-family dwellings | Initial outlet temperature 125 degrees F or less |
| Controls | Automatic temperature controls adjustable across the intended range |
Table 384.20-1m water heating standards (selected):
| Water heater type | Standard |
|---|---|
| One- and 2-family electric storage | UL/ANSI 174 |
| Oil-fired storage | UL/ANSI 732 |
| Gas storage, 75,000 BTU/h or less | CSA/ANSI Z21.10.1 |
| Gas storage over 75,000 BTU/h, and gas instantaneous | CSA/ANSI Z21.10.3 |
| Commercial electric storage and boosters | UL/ANSI 1453 |
| Electric instantaneous | UL/ANSI 499 |
| Solid fuel | UL/ANSI 2523 |
| Relief valves | ANSI Z21.22/CSA 4.4 |
| Relief valve drain tubes | ASME/ANSI A112.4.1 |
| Single-wall heat transfer fluid | NSF Category Code HT-1 |
The T&P valve, discharge pipe, vacuum relief and expansion-tank rules are in SPS 382.40 (sections 5.3 and 5.4).
Water treatment devices (SPS 384.20 (5) (r))
| Device | Standard |
|---|---|
| Aesthetic-effects treatment units (taste, odor, chlorine) | NSF/ANSI 42 |
| Residential cation exchange softeners | NSF/ANSI 44 |
| Health-effects treatment units | NSF/ANSI 53 |
| Ultraviolet microbiological systems | NSF/ANSI 55 |
| Reverse osmosis systems | NSF/ANSI 58 |
| Distillation systems | NSF/ANSI 62 |
| Lead content of system components | NSF/ANSI 372 |
- Devices must perform as asserted in their SPS 384.10 approval.
- A device that injects a compound must keep the concentration steady across its flow and pressure range.
- Compounds added to water must be listed as acceptable drinking water additives by an approved agency: US EPA, US FDA or NSF.
- If an unlisted compound is used, the department determines the backflow protection, and no outlet for human use may be downstream of it.
- Devices for contaminated supplies must be labeled with the manufacturer, trade name and model number.
Related SPS 382 rules:
- Softeners that discharge brine must regenerate on demand by meter or sensor (SPS 382.40 (8) (j)).
- Bypasses: a bypass is required except for devices serving no more than 2 outlets, and it is prohibited for devices reducing a contaminant to meet SPS 382.70 (3).
- Sampling valves are required at devices treating NR 809 or NR 140 contaminants.
- Waste: a device's waste discharge must be protected from backflow under SPS 382.41, and its drain tubing must meet Table 384.30-8 or 384.30-11.
- Fixture supply connectors downstream of a device serving one outlet may be up to 10 feet long.
Other appliances (SPS 384.20 (5))
| Appliance | Requirement |
|---|---|
| Residential clothes washers and clothes dryers | Integral air gap, or a Table 382.41-1 device |
| Residential dishwashers | Integral air gap or a Table 382.41-1 device; indirect waste rules in SPS 382.33 (9) (d) |
| Commercial dishwashers | ASSE 1004; air gap or air break to a trapped, vented receptor |
| Residential food waste grinders | ASSE 1008; drain at least 1-1/2 inches; adequate cold water supply |
| Commercial food waste grinders | Protected by a Table 382.41-1 device; drain at least 1-1/2 inches |
| Automatic ice makers | NSF/ANSI 12 |
| Chemical dispensing systems | ANSI/CAN/ASSE/IAPMO 1055 |
| Emergency showers and eyewashes | ANSI/ISEA Z358.1; tempered by ASSE 1071 mixing valves (SPS 382.40 (8) (g) 5.) |
| Personal hygiene devices on water closets | ASME A112.4.2/CSA B45.16 |
| Health care plumbing appliances | Must meet the SPS 382 drain, vent, supply and backflow requirements (SPS 384.15) |
| Water meters used for POWTS flow monitoring | AWWA C700 series |
Approvals behind the standards (SPS 384.10 to 384.12)
No fixture, appliance, material or device may be sold for or installed in a plumbing system unless it conforms to chs. SPS 382 to 384 and ch. 145, Stats. (SPS 384.10). Products in the Table 384.10 categories, such as POWTS components and treatment devices, need written department approval, which DSPS decides within 40 business days of a complete submittal. Under SPS 384.11, products must be listed by a nationally recognized, ANSI-accredited third-party agency acceptable to the department. Products that don't conform may use alternate or experimental approvals under SPS 384.50. SPS 384.12 requires each pipe length, fitting, trap, fixture and device to carry the markings its standard requires. Penetrations of fire-resistive walls and floors by plumbing must be protected under the commercial building code (SPS 384.13 points to chs. SPS 361 to 366).
Worked scenario
A combination boiler supplies radiant floors at 140 degrees F and domestic hot water from the same tank. Under SPS 384.20 (5) (p) 2., an ASSE 1017 mixing valve must cap the potable supply at 125 degrees F. The tank also needs a 3/4-inch drain valve with a hose-thread outlet, a T&P valve rated at least the burner input, and an expansion tank if a check valve makes the system closed.
A dual-use water heater supplies space heating water at 150 degrees F. What does SPS 384.20 (5) (p) 2. require for the potable hot water?
An ASSE 1017 mixing valve limiting potable hot water to 125 degrees F or less
An ASSE 1070 limiting valve at each lavatory, with no change made at the heater
A second water heater dedicated only to the potable hot water distribution system
No device, because the boiler aquastat already limits the potable water temperature
What drain valve must be installed at the lowest point of a water heater under SPS 384.20 (5) (p) 3.?
A 1/2-inch valve with a female thread
At least a 3/4-inch NPS valve with a male garden-hose-thread outlet
A 1-inch full-port ball valve with a capped end
No drain valve is required
Which standard applies to residential cation exchange water softeners in Table 384.20-2?
NSF/ANSI 58
NSF/ANSI 42
NSF/ANSI 55
NSF/ANSI 44
Sections you finish are checked off in the contents.