Lamps sometimes won’t light on a Montego Bay
Someone wrote me recently with a frustrating problem, but fortunately, the answer is fairly straightforward.
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I have an older Montego Bay 24 lamp Wolff bed that has developed a problem since we moved. When you turn the bed on, sometimes a few lamps won’t light up. Each time you turn it on, it is different lamps, and sometimes everything lights up fine. It wasn’t doing this before we moved. Did we damage it in the move?
(name withheld by request)
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Probably not. You don’t say what year the Montego Bay is, but I am guessing it is a model MB24C or D from the early 90s. These beds required 240VAC but didn’t have plugs, instead having a junction box on the bed and a 4 wire setup. In reality, the beds were 120V internally, but the amperage was greater than a standard 120V circuit, so a 240V was used and the voltage divided between the canopy and bench. They used Magnatek magnetic ballasts (great big old bricks…) Even the cooling fans are 120V. That is why it had 4 wires, two hots, a neutral and a ground.
Now, many electricians run 3 wires when you tell them that you need a dedicated 240V circuit, as most 240V appliances only need the two 120V hot wires and the ground. Many Montego Bay, Tan America, SunDash and SunMaster beds used to require (or still do) a true 4 wire setup to work properly, but when people try to connect them to a 3 wire system, sometimes things get weird. What usually happens is the electrician will try to combine the neutral wire and the ground wire “because they are joined at the main panel anyway”. This is what we call “floating the neutral” and sometimes works, but is not practice. In theory, this would work, although it is not the safest way to wire it, as you lose the dedicated ground. Very likely, your old house had the proper 4 wire circuit, and the new house doesn’t.
The solution is to have an electrician add the 4th wire, the nuetral, for a proper 4 wire, 30 amp, 10 gauge circuit and hardwire the bed to the circuit. This is what is required according to the owners manual. Once you have that done, the bed should work fine. Fortunately, those old magnetic ballasts are very hardy (but finicky) and it is hard to blow them up, so likely no damage was done. This will also restore the dedicated ground, which is a safety feature that you should always have with a tanning bed.
