Introduction
The Dometic DM2672 is a robust absorption refrigerator commonly found in touring caravans and motorhomes across the UK. While it generally provides reliable service with its three-way operation (gas, 12V, 230V), owners occasionally encounter a sharp, distinct odour that can be both alarming and potentially hazardous. This article focuses specifically on ammonia odours from the DM2672, offering a structured diagnosis guide, essential safety protocols, and practical repair pathways.
What Causes an Ammonia Smell in the Dometic DM2672?
An ammonia odour from your DM2672 is almost always a sign that the sealed absorption cooling unit has developed a leak. Inside that steel cylinder, a mixture of ammonia, water, hydrogen gas, and sodium chromate works through a thermal cycle to produce cooling. When a tiny crack or pinhole develops—often from corrosion, vibration, or age—ammonia vapour escapes into the living space. Unlike a food spill or mould, this smell is sharp, pungent, and unmistakable.
Other possible sources include a blocked burner jet (causing incomplete combustion in gas mode) or a failing flue baffle, but these produce more of a sooty or acrid smell, not the tell-tale ammonia. If you smell ammonia, treat it as a cooling unit failure until proven otherwise.
How Do I Safely Identify an Ammonia Leak in My DM2672?
Safety is paramount. Before you start sniffing around, recognise that ammonia is corrosive and toxic at higher concentrations. Follow these steps:
- Ventilate immediately: Open roof vents, windows, and the fridge’s external vent door. If you are in a confined space, step outside.
- Use your nose carefully: Do not inhale deeply. Sniff with short, gentle breaths near the front lower grille and rear vent area.
- Check for yellow residue: A fresh ammonia leak may leave a slightly yellow, greasy stain on the steel tubing or insulation around the cooling unit.
- Listen for hissing: With the fridge turned off and cooled down, place your ear near the rear of the unit—a tiny hiss indicates a pressurised leak.
- Do not use soapy water: Unlike propane leaks, ammonia reacts with water and can create caustic solutions. Stick to visual and olfactory checks.
If you confirm a leak, shut down the fridge completely and disconnect from gas and power. Do not attempt to patch or weld the cooling unit—it is a sealed system that requires professional replacement.
How Dangerous Is an Ammonia Leak From the DM2672?
Ammonia is toxic in elevated concentrations, but the small volume in an absorption fridge (typically 200–300 ml of ammonia solution) presents a low explosion risk. The immediate danger is respiratory irritation: burning eyes, coughing, sore throat, and difficulty breathing. Prolonged exposure in an unventilated RV can lead to more serious issues.
| Exposure Level | Symptoms | Action |
|---|---|---|
| Low (detectable smell, slight irritation) | Throat tickle, watery eyes | Ventilate, check for leak, schedule repair |
| Moderate (strong smell, coughing, nausea) | Burning in throat, headache, dizziness | Evacuate the RV, call a gas-safe engineer |
| High (overwhelming odour, breathing difficulty) | Severe coughing, chest tightness, confusion | Immediate emergency evacuation, call 999 |
If you experience any symptoms beyond mild irritation, do not re-enter the RV until it has been professionally ventilated. The long-term risks also include corrosion of internal metal fittings and electrical contacts, so a leak should never be ignored.
Can I Repair the Ammonia Leak Myself?
No. The sealed cooling unit in the DM2672 is a single-piece stainless steel assembly that cannot be repaired at home. Attempting to braze or epoxy a leaking joint will almost certainly fail and can create a dangerous situation. The only safe repair is to replace the entire cooling unit with a new or rebuilt unit.
- Cost of replacement: A new DM2672 cooling unit from a specialist supplier typically costs £350–£550, plus labour if fitted by a mobile engineer (allow £150–£250).
- Warranty route: If your fridge is under 2–3 years old, contact Dometic UK directly or your caravan dealer—some units have extended warranties covering cooling unit failure.
- DIY replacement: Technically possible if you are comfortable with gas systems, but you must have the replacement unit pressure-tested and the gas connection certified by a Gas Safe registered engineer. Most insurers will require this documentation.
Before you place the order, it is wise to read through our guide on Dometic DM2672 Temperature Fluctuations: Causes and Fixes because a failing cooling unit often shows unstable temperatures first.
How Do I Prevent Ammonia Odours in the Future?
While you cannot stop age-related corrosion entirely, you can delay it significantly with proper care. The DM2672 is sensitive to the way it is installed and operated:
- Level operation: Absorption fridges rely on gravity for the thermosiphon effect. Running the fridge more than 3°–5° off level (side-to-side) can cause the boiler to overheat and weaken the steel over time. Park as level as possible.
- Good ventilation: The rear of the fridge must have free airflow. Check that the external vent grilles are not blocked by leaves, mud, or insect nests. Clean them at least twice a year.
- Annual gas service: Have a qualified engineer inspect the burner, flue, and gas regulator yearly. A sooty burner can lead to overheating of the cooling unit.
- Check the door seals: A leaking door seal forces the fridge to work harder, raising internal temperatures and stressing the cooling unit. Follow our Dometic DM2672 Door Seal Replacement: Step-by-Step Guide to keep the cabinet airtight.
- Avoid overheating: On 230V mode, ensure the heating element is not running in a poorly ventilated cupboard. Overheating can accelerate the corrosion that leads to pin-hole leaks.
What Are the Costs of an Ammonia Leak Repair?
The total cost depends on whether you replace just the cooling unit or the entire fridge. Here is a realistic breakdown for UK owners:
- Cooling unit only (DIY install): £350–£550. You need a Gas Safe engineer to reconnect and test—add £100–£150.
- Mobile engineer supply and fit: £600–£850 including parts, labour, and certification.
- New DM2672 refrigerator: £1,000–£1,400 retail. This is the most expensive option but includes a complete fridge with new door, controls, and cabinet.
- Emergency call-out: If you need someone to isolate the gas and make the fridge safe, budget £80–£120 for a visit.
Bear in mind that a leaking cooling unit can also damage the fridge’s internal insulation, which may need replacement. Some owners find it more cost-effective to upgrade to a new fridge, especially if the DM2672 is over eight years old.
What Owners Say About Ammonia Odours in the DM2672
Long-term owners and caravan forums consistently report a few common patterns. First, the ammonia smell nearly always starts after the fridge has been unused for a period—during winter storage, for example—and is first noticed when the fridge is switched on in spring. Second, many owners note that the smell is strongest near the bottom front grille, not the rear compartment, which can be confusing. Third, the failure often follows a period of unstable temperatures—food freezing in the fridge section or the fridge not cooling at all—for a month or two prior to the leak. One experienced tourer from Devon remarked: “I smelled it once and knew instantly what it was. It’s not something you forget. The engineer said the cooling unit had a hairline crack at the weld.” Another owner from Scotland advised: “Don’t try to run it even for a day after you smell ammonia. It gets worse fast and the corrosive gas will eat the wiring loom.”
Frequently Asked Questions
Can I still use the DM2672 on gas if I smell ammonia?
No. Stop using the fridge immediately on all power sources. Gas operation can increase the pressure in the cooling unit, worsening the leak. Turn off the gas bottle at the regulator and disconnect the 12V and 230V supplies.
Will my insurance cover an ammonia leak repair?
It depends on your policy. Most standard caravan insurance policies cover sudden and accidental damage, but some exclude wear and tear or mechanical breakdown. Check your policy wording or call your insurer. Some owners have claimed successfully under accidental damage.
How long does a DM2672 cooling unit typically last before leaking?
With proper care—level usage, good ventilation, and annual servicing—a DM2672 cooling unit can last 8–12 years. Units in coastal or high-humidity areas may fail earlier due to corrosion. Units run on gas frequently tend to last longer than those used mainly on 230V.
Is it safe to sleep in the caravan with a small ammonia smell?
No. Even a faint odour indicates an active leak. Ammonia is heavier than air and will accumulate near the floor, where you and your family sleep. Ventilate thoroughly and arrange for repair before sleeping in the vehicle.
Can an ammonia leak affect the propane gas system?
Yes, indirectly. Ammonia vapour can accelerate corrosion of copper gas lines and brass fittings. If the leak is severe, the corrosive atmosphere can damage the gas regulator. Have your entire gas system inspected by a Gas Safe engineer after any ammonia leak has been repaired.
Should I replace the whole fridge or just the cooling unit?
If the DM2672 is less than 6 years old and in good cosmetic condition, a cooling unit replacement is cost-effective. For fridges over 8–10 years, replacement with a new unit is often better value, as you also get a fresh door seal, updated electronics, and a warranty. Consider also Dometic DM2672 Energy Efficiency Tips: Save Power While Camping to optimise your new fridge’s performance.
