Dometic 3-Way Refrigerator Venting Options

Correct venting is critical for a Dometic 3-way absorption fridge. The fridge removes heat through the rear cooling unit, so poor air flow can cause weak cooling, high cabinet temperatures and unreliable performance in hot weather.

This guide shows the common vent arrangements used with Dometic 3-way fridges. Use it as a starting point, then check the installation manual for the exact fridge model before cutting panels or changing vents.

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1. Overview

Dometic 3-way fridges are designed to cool well when the fridge cabinet is sealed from the living area and the rear cooling unit has a clear lower-to-upper air path.

• Gas supply and gas connections must be fitted and checked by an authorised gas fitter.
• The fridge recess should be sealed from the living area so exhaust gas or a possible gas leak cannot enter the van.
• The lower vent should not be blocked by an open door, awning arm, annex wall or stored gear.
• The fridge should sit on a hard, flat and level surface.
• Gaps beside and above the fridge cabinet should be controlled so warm air cannot recirculate around the cabinet instead of leaving through the top vent.
• A metal warm-air deflector is often needed to guide rising air out through the upper vent.

The lower vent should be level with the fridge floor where practical. If the lower vent is above the fridge floor, Dometic installations have commonly required a floor drain/escape hole for any possible gas leak. Confirm the current requirement against the fridge manual and gas fitter's advice.

The upper vent should sit above the cooling unit. As a simple rule, the bottom of the top vent should be at least level with, or above, the top of the refrigerator cabinet. Some vehicle designs make this difficult, but cooling performance is usually better when the warm air path is as direct as possible.

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2. Fridges up to 100L

Smaller 3-way fridges commonly use the AS1625 vent kit as the top and bottom side vents. The kit includes the aluminium flue connection and each vent has approximately 328cm² open area.

A T-piece and extension are used with this style of installation. Extra extensions may be required depending on the fridge height and the vent position.

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3. 101-200L fridges with roof vent

This layout is common in some motorhome installations. It uses a lower side vent, a roof vent base and cap, and a gas flue kit. It gives the warm air a direct path upward and out through the roof.

Some older Dometic roof vent base and cap parts are no longer available. The product cards below are useful for identification and service reference, but check the current Dometic fridge vent range before planning a replacement.

Use the matching gas flue kit for the installation colour and fridge layout.

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4. 101-200L fridges with two side vents

This layout is common in caravans and motorhomes where both fridge vents are fitted through the side wall. The bottom vent feeds cool air in and the upper vent lets warm air escape from the cooling unit.

The old 3109350.011 side vent referenced in older Dometic material is no longer available. For current installs, check the present vent range and the fridge installation manual rather than copying an old cut-out without confirming dimensions.

Use the matching gas flue kit where required.

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5. Large fridges over 100L

Larger Dometic 3-way fridges commonly use two LS300-style large wall vents. Each vent has approximately 667cm² open area, giving better air movement for the larger cooling unit.

Use the correct gas flue kit for the fridge and vent colour.

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6. Before cutting or changing vents

• Check the exact fridge model and installation manual.
• Measure the fridge cabinet, existing cut-outs and wall thickness.
• Confirm the lower vent, upper vent and flue positions before ordering parts.
• Make sure the warm air path cannot be blocked by insulation, cupboards, wiring or stored gear.
• Do not alter gas flues or gas connections unless you are an authorised gas fitter.
• If replacing the fridge as well as the vents, start with our Dometic 3-way fridge replacement guide.

If a Dometic 3-way fridge is not cooling properly, venting is only one possible cause. Also check level, gas flame, 12V/240V supply, thermostat operation and service condition. Our Dometic fridge troubleshooting guide covers the wider fault checks.