RV fridge smells like ammonia: stop and read this first

Common symptoms

• A sharp, eye-watering smell near the fridge, inside the RV or at the outside fridge vent.
• Yellow residue or staining at the back of the fridge, around the burner and boiler area.
• The fridge has stopped cooling, or cools much less than it did.
• A Norcold shows “no co” or “n”, meaning the board sensed the cooling unit stopped cooling.
• A Dometic RM1350 shows E3, which Dometic says means the cooling unit has malfunctioned.

Quick checks before anything else

• The fridge is off at its control panel.
• The fridge doors are still closed.
• Windows and the entry door are open, and nobody is inside.
• The propane to the fridge is off: the manual valve at the back of the fridge, or the tank valve.
• The fridge is unplugged from 120V at the back, through the lower outside vent.
• Nobody is smoking, lighting a stove or using a flame near the RV.

What causes an ammonia smell from an RV fridge?

Absorption fridges, the kind most Norcold and Dometic RVs have, cool with a sealed system called the cooling unit. Both makers say it is under pressure. Dometic says it holds ammonia, sodium chromate (a chemical added to slow corrosion) and other chemicals. An ammonia smell means that sealed system is very likely leaking.

• Crack in the boiler tube A Dometic recall notice describes a fatigue crack in the boiler tube that lets pressurized coolant escape.
• Leak elsewhere in the cooling unit A recall filing for Norcold 1200-series fridges describes a failure that lets the liquid solution leak out slowly.
• Damage from tools or impact Dometic warns that chipping frost with a knife or ice pick can create a leak in the ammonia system.
• Running far off level Norcold says running beyond its level limits can damage the cooling system.
• Not ammonia at all A rotten egg smell is propane. A smoky, fume smell comes from the burner area, which Dometic ties to a damaged or dislocated burner.

Why an ammonia leak is serious

Dometic says a high concentration of ammonia can cause fluid in the lungs and chemical burns to the eyes, lungs and skin, and the coolant can catch fire if it meets an open flame. Norcold says the contents can cause severe skin and eye burns and can ignite and burn with an intense flame. Repeated or long contact with sodium chromate can cause organ damage or cancer, Dometic adds. The burner, which sits right next to the boiler, is an open flame. That is why every step below starts with shutting off heat and getting people out.

Step-by-step: what to do when your RV fridge smells like ammonia

These steps follow the Dometic manuals, which list the most detailed owner response. Norcold’s manuals say the same thing in fewer words: do not repair or recharge the cooling system yourself.

1. Turn the fridge off at the panel Use the ON/OFF button on the front control panel. This stops the burner or the heater from heating a leaking system. Do not open the fridge or freezer doors.
2. Air out the RV and get out Open the windows and the entry door, then leave. Stay outside until the smell is gone. If anyone has trouble breathing or eye pain, call 911.

   

3. Shut off the propane Dometic says to turn off the manual LP gas valve at the back of the fridge, which you reach through the lower outside vent. If you cannot reach it without breathing the fumes, close the valve on the propane tank instead.

   

4. Disconnect 120V Unplug the fridge cord at the back, through the same lower vent. Norcold’s recall instructions also say to unplug through the service vent and disconnect from shore power. If you cannot reach the plug, switch off the fridge breaker in the RV panel.
5. Look, do not touch Once the smell has cleared, look at the back of the fridge through the lower vent with a flashlight. Dometic’s recall notice lists leakage or staining at the back, yellow residue at the back or sides, an ammonia smell, and poor cooling as signs. Norcold’s kit instructions say yellow residue around the heaters comes from the cooling liquid and may mean replacing the whole cooling unit. Do not wipe it with bare hands.
6. Do not restart it to test Dometic says never to try to solve a cooling problem by restarting the fridge again and again, and not to use it until it has been repaired. Norcold’s recall papers say extended operation of a leaking cooling unit could cause a fire, and that a leaking unit must not run in any mode until it is replaced.
7. Check for a recall Search your RV’s VIN at nhtsa.gov/recalls, and search the fridge brand under equipment. Norcold recall 10E-049 covers 1200, 1201, 1210 and 1211 fridges made on or before October 7, 2010, within set serial ranges, with a high temperature sensor kit as the fix. Dometic’s 2006 notice covers models including RM2652, RM2662, RM2852 and RM2862 made from April 1997 to May 2003. The model and serial number are on the label inside the fridge; read them only after it has aired out.
8. Call a tech for a diagnosis A sealed cooling unit cannot be patched or recharged by an owner. The fix is a new cooling unit or a new fridge. Dometic says refrigerant must be recovered by a licensed technician who is EPA certified, so leave removal and disposal to a shop.

Norcold vs Dometic: leak warnings and codes

Dometic. The DM, DMA and RM1350 manuals give the full list for an ammonia smell: turn it off at the front panel, do not open the doors, air out the RV and leave, close the manual gas valve at the back, unplug 120V at the back, and call for service. DMR and DMC models flash the left and middle temperature LEDs when the cooling unit has overheated (or its overheat thermostat is unplugged) and needs service. On the RM1350, E3 means the cooling unit has malfunctioned.

Norcold. Several Norcold boards watch the cooling unit. Some 1200 and N41X/N51X models show “no co” or “n” when it stops cooling; you can reset it once, and if it returns, call a dealer. Some larger models show “LI oP” when a high temperature limit switch opens. Our Norcold error code guide covers both.

12V compressor fridges do not use ammonia. Dometic names tetrafluoroethane as the refrigerant in its compressor models, so an ammonia smell points to an absorption fridge. For how the cooling unit works, see our RV fridge repair guide.

When to call an RV tech

• Any ammonia smell from the fridge, even if it fades.
• Yellow residue or staining at the back or sides of the fridge.
• A fume or smoky smell from the burner area.
• A “no co” or “n” code that returns after one reset, or “LI oP” on a Norcold.
• The fridge will not cool on any power source. Our RV fridge not cooling guide shows how to rule out the simple causes first.

Not sure the smell is the fridge? Our RV problem finder starts from the symptom.

Common questions