IMC 1006
What it means on the job
The discharge piping is right; the isolation valve is a serious violation. No shutoff valve of any kind is permitted between a boiler and its pressure relief valve. The relief valve is the last line of defense against a vessel overpressure, and a valve upstream of it means one person leaving one handle in the wrong position removes that protection entirely with nothing to indicate it. This requirement appears in IMC 1006 and in ASME BPVC Section IV for the boiler itself. The convenience being chased here is real — but the answer is a second relief valve or a planned shutdown, never an isolation valve.
Tested in 1 CraftIQ puzzle
- code-checkShutoff Valve Ahead of a Relief Valve
Related IMC sections
IMC 1104.1
Suction line (large line) must be insulated to prevent condensation and maintain efficiency. Uninsulated lines lose capacity and drip moisture causing water damage.
IMC 1105 / ASHRAE 15
This is correct. ASHRAE 15 and IMC require refrigerant leak detection in mechanical rooms when the refrigerant charge exceeds certain thresholds. R-410A is heavier than air, so the detector at 12" above floor is properly placed. The alarm and exhaust fan activation are required safety responses. Annual calibration meets the standard.
IMC 1203.4
Dissimilar metals (steel to copper) require dielectric unions to prevent galvanic corrosion. Without them, the pipe joint will corrode and fail within 2-5 years.
IMC 1205.1.6
This is a correct closed-loop arrangement, but note which code actually governs it. IMC 1009 is titled "Hot Water Boiler Expansion Tank" and sits in Chapter 10, whose scope is boilers, water heaters and pressure vessels — it does not reach a chilled water loop. Chilled water is scoped into Chapter 12, Hydronic Piping, and Chapter 12 imposes no expansion-tank requirement at all: the tank is an engineering necessity, not an IMC command. The section that actually decides this scenario is IMC 1205.1.6, which requires shutoff valves only at connections to NONDIAPHRAGM-type expansion tanks — so a diaphragm tank with no isolating valve is compliant, and that contrast is the thing worth remembering. The tank absorbs expansion across the loop's own temperature range, including warm-up and shutdown, not "as it heats" the way a boiler loop does. Two details here are good engineering practice rather than code: connecting at the pump suction puts the point of no pressure change where it belongs so the pump adds pressure to the loop, and the air separator upstream keeps entrained air out of the tank.
IMC 304 / Manufacturer Specs
The installation meets the manufacturer's minimum clearances. Equipment clearances are determined by the manufacturer's listing and installation instructions, which are enforced by code. As long as the actual clearances meet or exceed the listed minimums, the installation is compliant.
IMC 304.1 / Manufacturer installation instructions
While the height and distance from the register are acceptable, direct sunlight on a thermostat causes false high temperature readings, making the AC run excessively. Thermostats must be installed away from direct sunlight, heat sources, supply registers (min 3' is borderline), and exterior walls. The sunlight exposure is the primary violation here.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.