Dimplex Opti-Myst® Linear Vapor Electric Fireplace Size Guide
Framing dimensions, electrical requirements, water system requirements, and fresh air inlet specifications for the 46", 66", and 86" Opti-Myst® Linear models.
Overview
What this guide covers
This guide covers the physical framing, electrical, fresh air inlet, and water system requirements for the Dimplex Opti-Myst® Linear Vapor Electric Fireplace, available in 46" (OLF46-AM), 66" (OLF66-AM), and 86" (OLF86-AM) widths.
The Opti-Myst® Linear uses ultrasonic water mist technology rather than a standard LED flame system. This creates installation requirements that differ from conventional electric fireplaces — particularly the mandatory fresh air inlet and the optional but recommended plumbing connection. Both are covered in dedicated sections below.
All values on this page are sourced from the Dimplex installation manual. For product pricing and availability, see the Dimplex Opti-Myst® Linear product page. To compare this model against other Dimplex electric fireplace series, see the Dimplex Electric Fireplace Comparison Guide.
Fit Requirements
All dimensions from the Dimplex installation manual
Overall Unit Dimensions
| Model | Overall Width | Overall Height | Overall Depth | Viewing Area W × H |
|---|---|---|---|---|
| OLF46-AM — 46" | 47-1/2" | 31-1/2" | 11-7/8" | 44-1/4" × 14-3/8" |
| OLF66-AM — 66" | 67-1/2" | 31-1/2" | 11-7/8" | 64-1/4" × 14-3/8" |
| OLF86-AM — 86" | 87-1/2" | 31-1/2" | 11-7/8" | 84-1/4" × 14-3/8" |
Framing Dimensions (Structural Rough Opening)
The framing height is consistent across all three models. Width and depth minimum values apply to all three.
| Model | Framing Width (min) | Framing Height | Framing Depth (min) |
|---|---|---|---|
| OLF46-AM — 46" | 48" | 32-1/2" | 12" |
| OLF66-AM — 66" | 68" | 32-1/2" | 12" |
| OLF86-AM — 86" | 88" | 32-1/2" | 12" |
Drywall Opening (Finish Opening Through Drywall)
The drywall opening height is consistent across all three models. Dimensions allow for a 2 mm clearance all around the unit.
| Model | Drywall Opening Width | Drywall Opening Height |
|---|---|---|
| OLF46-AM — 46" | 46-3/16" | 17-1/2" |
| OLF66-AM — 66" | 66-3/16" | 17-1/2" |
| OLF86-AM — 86" | 86-3/16" | 17-1/2" |
Not Load-Bearing
This fireplace is not load-bearing. The opening must be framed so that the weight of building materials above does not create pressure on the top of the unit.
Recommended Mounting Height
For an optimized viewing angle of the flame effect, the installation manual recommends mounting the bottom of the unit between 5" and 50" from the finished floor. This applies to all three models.
Fresh Air Inlets
Required for all models — must be planned into framing
⚠️ Fresh Air Inlet Required
Failure to include a fresh air inlet will result in poor flame performance and damage to the fireplace. The air inlet must allow an air path to reach the underside of the unit and must be incorporated into the framing and drywall installation.
Each model requires a specific minimum inlet area. If the inlet is concealed with a decorative grille, the open area of the grille (not the overall grille size) must meet the minimum. Any grille coverage must be compensated for by increasing the total opening size.
Inlet configuration options documented in the manual include a recessed inlet below the unit, a front-face register below the glass, or side registers on each side of the fireplace. For side register configurations, the manual recommends including an opening on each side for best results.
| Model | Minimum Air Inlet Area |
|---|---|
| OLF46-AM — 46" | 80 in² |
| OLF66-AM — 66" | 120 in² |
| OLF86-AM — 86" | 160 in² |
Optional Air Intake Grille Accessory
Dimplex offers an optional Air Intake Grille accessory (part number X-00275) designed for concealing the fresh air inlet opening while maintaining required airflow. Contact Serene Yards for availability.
Electrical Requirements
All values from the Dimplex installation manual
Voltage and Wiring
All three models support both 120 V and 240 V operation. The installation method differs by voltage: 120 V uses a 3-wire supply (L1, Neutral, Ground); 240 V uses a 4-wire supply (L1, L2, Neutral, Ground). Hardwire is the primary installation method for both voltages. A plug-in option is available only for 120 V installations via the optional OLFPLUG accessory kit (sold separately) — do not use an extension cord with this unit.
The installation manual recommends a dedicated 15 Amp circuit rated for the appropriate voltage. A dedicated circuit is required if the circuit breaker trips or fuse blows regularly during heater operation.
For bathroom installations, the unit must be protected by a GFCI receptacle or circuit. The unit is not watertight.
Power Draw by Model and Mode
| Model | 120 V Full Heat | 240 V Full Heat | Flame Only (no heat) | Amps at 120 V | Amps at 240 V |
|---|---|---|---|---|---|
| OLF46-AM — 46" | 1,220 W | 1,920 W | 520 W | 10.2 A | 8.0 A |
| OLF66-AM — 66" | 1,480 W | 2,180 W | 760 W | 12.3 A | 9.0 A |
| OLF86-AM — 86" | 1,020 W* | 2,400 W | 1,020 W | 8.5 A | 10.0 A |
OLF86-AM — 86" Model: No Heat at 120 V
When the 86" model is connected to 120 V, the installation manual states that there will be no heat output. The mist system and fans will operate normally for the flame effect, but heat functions will not produce warmth. Full heating capability on the 86" model requires a 240 V dedicated circuit.
Heater and Flame Effect — Independent Operation
The heater and the Opti-Myst® mist system operate independently of each other. The flame effect can be run with the heater off (flame-only mode) on all three models. The heater can also be permanently disabled by removing a hardware jumper on the main control board — useful for installations in commercial spaces or warm climates where heat output is not desired.
When heat is turned off during normal operation, the fan continues to run for 30 seconds to dissipate residual heat before shutting down. The mist flame effect continues uninterrupted.
Certifications
All three models are cULus Listed, File E71416. Standards referenced: UL 2021 and CSA C22.2 No. 46. All models also comply with FCC Part 15 Rules for Class B digital devices.
Water System Requirements
Unique to the Opti-Myst® — does not apply to LED-based electric fireplaces
What Makes the Opti-Myst® Different
Unlike LED-based electric fireplaces, the Opti-Myst® Linear creates its flame effect using ultrasonic transducers that atomize water into a fine mist, illuminated by LED lights. This means the fireplace requires a water source to produce the flame effect. Planning for water supply during the framing stage is strongly recommended.
Water Supply Options
Hard-plumbed connection (recommended for frequent use). The units are designed to connect to a cold-water supply line using standard 1/4" O.D. tubing. The water connection is located at the bottom left rear corner of the firebox — plan framing to allow routing the cold-water line to this location. An optional plumbing accessory kit (CDFIPLUMB-KIT) designed for use with 1/4" copper piping is available. The unit includes an overflow sensor that automatically shuts off the water supply if an overflow is detected.
Refillable water containers (not recommended for frequent use). If a plumbing connection is not available, the reservoir can be manually filled using optional refillable containers (part number 9601350100RP, sold separately at dimplex.com/replacement_parts). One container is required per flame module. One fill provides up to 6 hours of flame operation. Refilling requires removing the front glass and media tray each time.
Water Type
Normal tap water is acceptable. In areas with hard water, the installation manual recommends using a water softener, as mineral content may require more frequent cleaning and maintenance of the mist system components. Unfiltered water from a well or unmonitored supply is not recommended. The unit includes an in-line mesh filter to help remove contaminants and extend product life.
Maintenance Requirements — Mist System
The Opti-Myst® mist system has documented maintenance requirements that standard electric fireplaces do not. The installation manual specifies the following schedule.
- Monthly (minimum): Clean the top cover, sump, water bottle (if used), and transducers with soap and water. More frequent cleaning may be required depending on water quality. Do not put plastic components in the dishwasher.
- As needed: Clean the air filters by rinsing with water, drying on a towel, and reinstalling with the coarse black side facing the back of the unit.
- Annually (minimum): Inspect the heater for dust and dirt accumulation. The heater must not be operated with significant dust buildup as this can cause heat accumulation and damage.
- Priming: The unit must be primed with water before first use and after any time the sumps are fully emptied (such as after cleaning).
Transducer Replacement
The ultrasonic transducers are consumable components. After prolonged use, mist production may become reduced. If cleaning does not restore performance, transducer replacement is required. Replacement transducers are included in the box with each unit (2 for the 46" model, 3 for the 66" model, 4 for the 86" model). Additional transducers (part number 9601210100RP) can be purchased at dimplex.com/replacement_parts. The installation manual provides removal instructions: release the retaining tab in the sump and remove the transducer.
⚠️ Warm-Up Period Required
After powering on, there is a 3-minute warm-up sequence before the flame effect starts. This is normal operation and applies to all three models. Plan for this delay in commercial or hospitality applications where the flame effect is expected immediately on power-up.
Installation Notes
Key requirements from the installation manual
Installation Type
The Opti-Myst® Linear is designed for recessed built-in installation into a framed wall opening only. No wall-mount, surface-mount, freestanding, or insert configurations are documented in the installation manual. Two people are recommended for installation.
Electrical and Water Routing
Field wiring enters at the top right rear corner of the firebox. The cold-water connection is at the bottom left rear corner. Both routes must be planned during the framing stage — plan framing to allow routing the electrical cable and cold-water line to their respective locations before the unit is set.
Outdoor Use
Indoor Use Only
The installation manual explicitly states: "Do not use this fireplace outdoors." The unit is not weatherproof or watertight.
Mobile Home Approval
Mobile home approval status is not specified in the installation manual.
Size-by-Size Reference
All dimensions from the Dimplex installation manual
46" Model — OLF46-AM
Overall Unit Dimensions
Viewing Area
Framing Dimensions
Drywall Opening
Electrical & Air Inlet
66" Model — OLF66-AM
Overall Unit Dimensions
Viewing Area
Framing Dimensions
Drywall Opening
Electrical & Air Inlet
86" Model — OLF86-AM
240 V Required for Heat
When connected to 120 V, the 86" model operates the mist system and fans but produces no heat output. Full heating capability requires a 240 V dedicated circuit.
Overall Unit Dimensions
Viewing Area
Framing Dimensions
Drywall Opening
Electrical & Air Inlet
Frequently Asked Questions
All answers sourced from the Dimplex installation manual
What framing depth does the Dimplex Opti-Myst® Linear require?
All three Opti-Myst® Linear models require a minimum framing depth of 12 inches. The units must be built into a framed wall opening — surface-mount and freestanding configurations are not documented in the installation manual. An opening beneath the unit must also be included in the framing to allow airflow to reach the underside of the unit.
Can the Opti-Myst® Linear flame effect run without heat?
Yes. The heater and mist system operate independently. The flame effect can be run in flame-only mode with the heater off. On the 46" model, flame-only mode draws 520 watts; on the 66" model, 760 watts; on the 86" model, 1,020 watts at 120V. This allows year-round use of the flame effect without generating heat.
Does the Opti-Myst® Linear require a plumbing connection?
A plumbing connection is strongly recommended for frequent use. The unit connects to a cold-water supply line using standard 1/4" O.D. tubing. An optional plumbing kit (CDFIPLUMB-KIT) is available for copper piping. If a water line is not available, optional refillable containers (sold separately) provide up to 6 hours of flame operation per fill, though the installation manual notes this approach is not recommended for frequent-use applications.
What type of water should be used in the Opti-Myst® Linear?
Normal tap water is acceptable. In areas with hard water, the installation manual recommends using a water softener, as mineral content may require more frequent cleaning of the mist system components. Unfiltered water from a well or unmonitored supply is not recommended. The unit includes an in-line mesh filter to help remove contaminants.
What fresh air inlet area is required for the Opti-Myst® Linear?
A fresh air inlet is required for all models and must be planned into the framing and drywall installation. Required minimum inlet area: 46" model requires 80 square inches; 66" model requires 120 square inches; 86" model requires 160 square inches. If the inlet is concealed with a grille, the open area of the grille must meet the minimum — any grille coverage must be compensated for with a larger overall opening.