Common Issues with Ammonia or 3 Way Fridges

Introduction

Ammonia Fridges, also known as Absorption or 3 Way Fridges, use technology dating back to the 1850's. The refrigerant used in these fridges has a high boiling point and therefore requires high temperatures to evaporate, and it relies on either a gas flame or an electric heating element to generate those temperatures. A lot of energy is required to generate such high temperatures, and the heat produced then needs to be removed and isolated from the cold inside parts of the fridge. In this article, we list some common questions about the absorption of ammonia in fridges.

Why does my fridge sometimes get cold and other times not, for no apparent reason?

• At the beginning of this article, we mentioned that Ammonia or 3 Way Fridges rely on heat for cooling, but they are also dependent on gravity. The fridge has no pump to force the refrigerant around, so it will not work correctly if the vehicle is not parked on flat ground. Newer Ammonia Fridges suffer less from this problem as the refrigerant flow's design angle has been increased.
• On a hot summer day, if the fridge side of the vehicle is in full sunlight, it might get so hot that the fridge can no longer remove the excess heat building up inside the fridge cavity. This can cause the inside of the refrigerator to defrost, but once the sun goes down, the fridge should start working again.

• If the fridge works on gas but not on 240 volts, then the 240-volt heating element may be burnt out. To check this, look at the 240-volt circuit breakers to see if they have tripped out.
• If the element is burnt out, it can be replaced, but the fridge must be removed in most cases.

• The flue is dirty, so the fumes cannot pass through the flue efficiently. This mostly happens after the vehicle has been in storage for a while. Insects can make the flue their home, causing an incorrect gas-to-air ratio.
• The burner is dirty, mainly due to rusty flakes from the flue stack that land on it.
• The capacitor to the igniter is blown. If you cannot hear a clicking noise, which creates the spark when you turn the fridge onto "GAS", or with an old fridge when you manually push the ignition button, and there is no visible signs of a spark through the looking glass, then a component of the igniter is faulty, and you should seek advice.
• The gas lights will not stay on: the fail-safe device on the burner is faulty or incorrectly set, and the fridge needs servicing.

• This should not happen under any circumstances. Please do not use the fridge at all until it has been serviced.
• If the fumes smell of LPG, you are at risk of a fire or explosion.
• If the fumes smell similar to exhaust gasses from a car, you are in danger of carbon monoxide poisoning, also known as the silent killer. Sleeping in such an environment is very dangerous.

• The 3-way Fridge should never work on the battery if the engine is not running. Most vehicles are wired so that the fridge will not operate on 12 or 24 volts when the engine is off. This is because the energy consumption at 12 volts on a three-way fridge is so high that it will only work when the engine alternator generates enough power to operate the 12-volt heating element at the back of the refrigerator.
• The 12-volt element could be blown, or the wiring to the 12-volt part may be faulty. Complete removal of the fridge is usually required to repair this fault.
• If the fridge does not work even when the engine is running, a fuse may be blown, or the 12-volt heating element may be blown. The element can be replaced, but often the fridge must be removed to do this

If you have decided that the fridge is past its prime, then you could replace it with an efficient 12-volt compressor fridge that will run as long as it has a power source. See what we have available