Frequently Cited Mechanical Issues

1. Equipment

  • HVAC products and equipment are to be installed according to the manufactures installation instructions, product listing and the MMC 2015 and MRC 2105. This also includes power vent water heaters, Tjernlund power venters, bath fans, gas fireplaces, dryer exhaust, A/C condensate and condensate pumps.
  • Gas Appliances shall not be located in sleeping rooms, bathrooms, toilet rooms, storage closets, or in a space that opens only into such rooms, except where the installation complies with one of the exceptions listed in section G2406.2 of the MRC 2015
  • All wall furnaces, space heaters, furnaces and mechanical equipment have minimum required clearances that must be maintained to prevent fire and provide service access to the equipment. A 30” x 30” servicing clearance is required on the front or service side of the equipment.
  • Laundry rooms and mechanical rooms require makeup/combustion air equivalent to the air being removed. Section G2407 of the MRC 2015 covers the approved methods. Consult manufactures instructions, they may not allow combustion air for furnaces to be taken from a laundry room due to contaminants in the air.
  • Equipment located on roofs over 16’ above grade require a permanent interior or exterior means of access be provided. Guards shall be required where equipment is located within 10’ of roof edge, guards shall extend upwards 42”, and 30” beyond the equipment requiring service.
  • Equipment mounted on rubber type roofing membrane require slip sheets under equipment and blocks on the roof to protect the roofing membrane.
  • All NEW outdoor ground mounted equipment (not replacement equipment, in the same location, that was legally installed) will need to have the location reviewed by the Planning Dept. here at 1120 Monroe SW, submitting a site plan showing lot lines, structures, the street and with the equipment location, helps speed the process.
  • Commercial properties require equipment to be located off the ground or an Administrative Departure will be required.
  • Residential ground mounted equipment is required to be set on a pad 3” above ground level, 3’ from property lines, not in the front yard, and shielded from view from the street or an Administrative Departure will be required from the Planning Dept.
  • 90% and up, condensing furnaces and/or air conditioning coils in or near where water leakage could damage any building component, (walls, base plates, carpet, flooring, drywall, etc.) need a form of overflow protection.
  • Overflow protection can be a pan under the furnace that is piped to direct the water to a drain or a pan under the furnace with the drain plugged and a switch installed in the pan that shuts the equipment down (this will cover the a/c coil too). Pans need to be 1.5” deep and 2” larger than equipment, furnace needs to be on risers above the bottom of pan to prevent water damage.
  • Replacement furnaces will require a programmable setback thermostat if the thermostat is changed, new installs are required to have a programmable setback thermostat.
  • All piping and penetrations through the exterior of the building need to be sealed.
  • Piping carrying fluids under 55 degrees F and over 105 degrees F need to be insulated with a minimum R-3 insulation

2. Air Conditioning

  • Where water leakage could damage any building component, (walls, base plates, carpet, flooring, drywall, etc.) a form of overflow protection is required. A/c coils can use an overflow sensing switch installed in the secondary drain opening in the pan and wired into the furnace control system.
  • Air conditioning suction tubing requires R4 insulation from the coil box to the service ports on the compressor.
  • Insulation exposed outside is to be protected from UV deterioration, weather and physical damage. Wrapping the insulation with tape is not an approved protection method.
  • The line set is to be supported every 6’ with hangers that do not cause galvanic corrosion to the copper tubing.
  • Air conditioning coils need the extra drain openings sealed with threaded plugs (not the push in plastic shipping cap).
  • Service ports on condensing units need caps installed and secure.
  • Minimum 16 gauge steel nail guards are required where line sets pass thru any wood framing within 1 1/4” of the face of the framing, and shall extend 2” below a top plate and 2” above a bottom plate.

3. Dryers

  • Dryer exhaust piping is to be run in hard pipe a maximum of 35’ developed length unless dryer is on site and manufacture has rated it for greater length, for lengths over 35’ duct is to be labeled for developed length within 6” of dryer connection.
  • Duct is to be installed with insert end extending into next duct or fitting, in the direction of flow, with piping supported every 4’. Piping and fittings to be taped and sealed. Screws and rivets that protrude into the duct are prohibited.
  • Dryer exhaust must terminate on the outside of the building with a backdraft damper and no screen. Exhaust openings to be 3’ from openings into the building and ventilated soffit.
  • Minimum 16 gauge steel nail guards are required where dryer exhaust ducts pass thru any wood framing within 1 1/4” of the face of the framing and shall extend 2” below a top plate and 2” above a bottom plate.

4. Exhaust and Ventilation

  • When the interior of any building or room is stripped down to bare studs the space will need to comply with current ventilation requirements for exhaust and air change rates for the building based on use and size.
  • Minimum Bathroom fan requirements: 50 cfm intermittent or 20 cfm continuous run. Exhaust openings will need to be 3’ from openings into the building and ventilated soffit.
  • Minimum Kitchen exhaust fan requirements: 100 cfm intermittent or 50 cfm continuous run. Exhaust fans over 400 cfm in size will require makeup air to be provided equal to the exhaust rate. Exhaust openings are to be 3’ from openings into the building, ventilated soffit and 10’ from mechanical air intakes, unless located 3’ above mechanical air intake opening.

5. Condensate Pumps

Hose clamps need to be installed on discharge tubing at pump.

Condensate pump overflow protection needs to be wired in when pump is not fully in the furnace pan, when located in a space where water damage could occur.

Vinyl tubing needs to be mounted and supported every 18”. And is not allowed in concealed spaces, plenum rated ceilings or fire rated assemblies.

6. Water Heaters

Water heaters or hot water storage tanks that are installed in locations where leakage of the tanks or connections will cause damage, the tank or water heater shall be installed in a galvanized steel or aluminum pan having a material thickness of not less than .0236 inch (24 gauge) or other pans approved for such use. Plastic pans are not approved for use with gas water heaters. The pan drain shall extend full-size and terminate over a indirect waste receptor or shall extend to the exterior of the building and terminate not less than 6 inches and not more than 24 inches above the adjacent ground surface. The City allows the use of a water sensing alarm in the pan when a drain is not available.

7. Venting

  • Where an appliance is permanently disconnected from an existing chimney or vent, or where an appliance is connected to an existing chimney or vent during the process of a new installation, the chimney or vent shall comply with current code.
  • Resizing: The chimney or vent shall be resized as necessary to control flue gas condensation in the interior of the chimney or vent and to provide the appliance served with the required draft.
  • The flue gas passage way shall be free of obstructions and combustible deposits. The flue liner, chimney inner wall or vent liner inner wall shall be continuous and free of cracks, gaps, perforations or other damage or deterioration that would allow escape of combustion products, including gases, moisture and creosote.
  • Chimney liner systems shall be sized and installed according to the manufactures instructions. The chimney top plate shall be sealed and secured in place, the mud collar installed and sealed to the chimney and the liner visible for inspection. A B vent to liner adapter is required for connecting B vent to a chimney liner.
  • Single wall Tee or Wye cannot be used between B vent and chimney liner.
  • Most 80% furnaces under 80,000 BTUs will require B vent from the furnace to the liner.
  • Single wall vent connectors need to be 26 gauge galvanized metal and have 6” of clearance to combustibles. B vent is required where a vent goes through an unconditioned space and B vent requires 1” clearance to combustibles.
  • Where B vents pass through insulated assemblies an insulation shield of 26 gauge steel shall be installed to maintain required 1” clearance and secured to prevent movement, the shield needs to extend 2” above insulation materials.
  • Band clamps on furnace connections to PVC piping need to be tightened in place.
  • 2” PVC piping needs to be supported every 4’ with approved hangers.
  • All PVC piping on vents, drains and terminations needs to be primered with colored primer and glued fully seated into the fittings.
  • Vent and Intake pipe openings need to be 24” off the ground when not using a flush mount side wall termination kit, to allow for local snow level.

8. Ducts

  • Where new duct systems are installed, remodel or in new construction, a copy of the Manual J, S and D (heat loss, load size and duct layout) are required to be submitted before a rough-in inspection.
  • All new duct work needs to be sealed with approved materials before insulating, including takeoff connections and swivel joints (gores) on elbows and adjustable takeoffs.
  • Inner liner of flex duct needs to be secured to takeoffs.
  • Thermo-pan requires fasteners every 2” per manufacture.
  • Return air chase penetrations and headers need to be sealed with material rated for use in air stream, not orange foam (it out gases).
  • Draft stopping needs to be done around duct penetrations between floors and ceilings. Unless it is a fire rated assembly, then an approved fire stopping system is to be used.
  • Return air stud chase cut-outs need sheet metal angle plates to seal return chase to floor (behind drywall).
  • 16 gauge galvanized metal ties 1 1/2'” wide are required when more than 50% of an exterior or load bearing wall is cutout of a top plate, ties are to extend 6” past the opening.
  • New construction register boots need to be sealed to the assembly they pass through. (floor, ceiling, sidewall)

9. Electrical

  • All electrically powered equipment needs an approved means of disconnect in the same room as the equipment. Mini split evaporator heads powered from outside need a double pole disconnect in the same room with head. Outside equipment needs a disconnect within site of equipment.
  • All 110 volt wire nut connections are required to be in an enclosed junction box.
  • Line voltage wiring running through a furnace sidewall, electrical boxes, and bare end conduits require bushings to protect wiring from damage.
  • The Furnace is required to be on a separate dedicated circuit and labeled in the panel.
  • Breakers and fuses for the equipment need to match the maximum fuse rating on equipment.
  • Electrical outlet receptacles in unfinished spaces are required to be GFI type.
  • On new wiring installations for equipment, a GFI electrical outlet receptacle needs to be within 25’ of the equipment.

10. Gas Piping

  • CSST flexible gas piping needs to be installed according to the manufactures instructions.
  • Where Black coating on CSST is removed past required amount for connection, exposed CSST is to be wrapped with approved silicone tape.
  • CSST fittings are not rated for use as unions, an actual threaded union is required as a disconnection means at the equipment.
  • CSST is not allowed to be run through the sidewall of a fireplace with a vertical vent.
  • CSST piping is to be secured and supported according to manufactures instructions, this includes securing overhead drops to equipment.
  • CSST piping requires tempered nail guards where piping is passing through top or bottom plates and is closer to the face of the framing than ¾”, plates are to extend 2” past piping in all directions. Horizontal piping will require 1 ½”wide tempered plates when piping is closer to the face of the framing than ¾”, plates are to extend 2” past pipe.
  • Gas shutoff valves for fireplaces need to be securely mounted and accessible.
  • Any time gas equipment is changed or installed, the gas valve will be used, this valve will need to be an approved gas shutoff valve.
  • Any exposed steel gas pipe is required to be coated/painted to protect it from corrosion.
  • Sediment trap or drip legs are required for space heaters.
  • Sediment trap or drip legs are not to be installed in a running tee configuration, but as a drop at the end of the line before the gas control valve.
  • Gas piping is to have approved metal hangers over drop to equipment to support piping and prevent damage to the control valve.