We often get calls from customers about why their refrigerator won’t turn on even though it’s got 120 Volts at the plug, so I feel like a quick explanation of the electronics and electricity required would benefit everyone.
There are three main systems in a standard ammonia refrigerator used by the RV and Boat industry. The control board system, the electric heating system, and the propane system. Each of these systems is powered differently. To fully operate the refrigerator in any mode all three systems must be in good working order. Each system and it’s primary criteria for correct operation are explained below.
Control Board System: This system consists of the front panel controls as well as the main control board located at the rear of the refrigerator. both of these boards must have a minimum of 10.5 volts DC supplied to them to operate. Anything less and they will not appear to function at all. More than 15 volts DC will also cause significant problems, so keep your battery and charger maintained.
Electric Heating System: This system consists of the electric heating elements and the 120 volts AC wiring and outlet. The standard heating elements are activated by supplying 120 volts AC to them. This is only accomplished if the Control Board System allows the 120 volts AC to flow through to the heating elements. So you can start to see why just having one source of power is not enough. To get another connection or get new power source, you might want to contact an emergency electrician Sydney or someone near you. This system may also consist of a 12 volt DC heating element on a three way refrigerator. This is less and less of a common option all the time, so unless you know that you have three way refrigerator don’t worry about it.
Propane System: This system consists of all the components that are required for a good quality propane flame to be present. These include the propane tank, hoses, Woodward Solenoids, orifice, burn tube, shroud, and baffle/flue. Since this conversation is about the electrical portions being misunderstood we’ll cover the actual function of each of those components later. The lesson here is that for all those components to work properly you must have a filled propane tank with all shut-off valves set to the open position and once again a good DC power source to the control board. Unless the Control Board System allows the solenoid to open, thereby allowing gas to flow, and then allowing the striker to ignite the propane, the propane system will not work.
Customers should not attempt to repair propane refrigerators or other propane appliances on their own, even if they have this information. If one might have noticed, even expert technicians may make use of insulating gloves at Unigloves (or similar platforms) before they start working on the repairs. Without prior knowledge, if they start working or attempt to do the repairs on their own, accidents and serious injuries may occur. Sometimes, it could even lead to bigger problems where you might have to spend a fortune again to refurbish everything back to its original state. Therefore, in the event of such problems, customers should contact their local propane supplier (such as Kelly Propane) so that the clientele can speak with their service executives and resolve the issues.
Returning to our previous topic of discussion, in conclusion, having only DC power, or only AC Power, or only Propane, does not supply you with the necessary operating parameters for any current refrigerator on the market today. You must always have DC (Battery) power above 10.5 volts and one other power source, unless you have the rare three-way refrigerator which will continue to cool with only DC (Battery) power supplied.
Written by Weston Moore
Thank you for sharing your knowledge. I do have a question. At the 12 volt dc terminal, I get 29 ac volts, which is the same ac voltage at the Rv battery. I read that I shouldn’t get more than 6 V AC at the terminal block, as stated in a diagnostic service manual. Any suggestions on what to look for?
Written by Prentis Henry
That is quite a lot of VAC on the DC line. My guess is your converter for the coach is not filtering the AC like it should or the power board on the refrigerator is not isolating the AC like it should.
Either will most likely need to be replaced unless you feel comfortable diagnosing and repairing circuit boards at the component level.
If it is the converter you will see AC on all your DC lines. Most lighting and other simple components won’t mind , but sensitive appliances like the refrigerator will. To confirm this I would pull all the fuses on the DC fuse bank and check to see if you have AC voltage on the main terminal off the converters DC output while on shore power. That should confirm the suspicion.
To diagnose the power board isolation, simply unplug it from the AC outlet and run it on propane. If the AC ripple is removed, replace the power board.
Let me know if that helps.