Motor starter problem

[LBF Carwash]

Hello, new carwash owner here. I have a Coleman Hanna system that is 25-30 years old. Upon purchase of the carwash only 1 bay was working properly, but I have since gotten 3 of the 4 working correctly. My issue is with the last bay and no high pressure. When I put coins into the bay meter and select the high pressure function the coil on the contactor is not pulling in. I am a maintenance technician/electrician by trade and I have checked the control voltage at the contactor but only get 12-13 bolts when the switch is turned to this function. It is a brand new switch that was installed by my father. I’m thinking the contactor is bad but i have done a continuity check with power off and it seems to be fine. Any suggestions?

 

[MEP001]

You need to check voltage from "hot" to "common." Car wash voltage is two legs of 12 volts that read 12v to ground but 24v across the terminals. Read voltage across the contactor inputs (A1 and A2) for 24v. If you have that, the contactor's coil is bad.

 

[LBF Carwash]

You need to check voltage from "hot" to "common." Car wash voltage is two legs of 12 volts that read 12v to ground but 24v across the terminals. Read voltage across the contactor inputs (A1 and A2) for 24v. If you have that, the contactor's coil is bad.

I have checked the voltage and I have the correct voltage. When I turn the rotary switch to high pressure it doesn’t do anything

 

[MEP001]

Make note of the wire color and follow it back to the contactor.

 

[LBF Carwash]

Make note of the wire color and follow it back to the contactor.

The wire colors match from the rotary switch all the way back to the contactor. I’m going to unwire the switch and check it. This has thrown me for a loop.

 

[MEP001]

You also have to check voltage on those wires all the way to the inputs at the contactor, usually A1 and A2.

Have you physically checked the contactor when it should be running? Does it make any noise?

 

[LBF Carwash]

Yes I have checked the contactor and the overloads. When I checked between A1 and A2 I do not have 24v. That is what makes me think it is the switch

 

[MEP001]

Then check at the switch. If you get power there, keep checking down the line. Make sure the jumper between the stacks is there (11 and 21 for 8-position or 10 and 20 for 10 position).

 

[KFPanda]

I ran into this issue at my Coleman wash today. Difference is it only added an hour or so to my daily check. When I found these symptoms in the bay I closed it and tried the contactor. Motor and pump were fine but obviously contactor not energizing. Back at bay switch is old and a little wobbly so possible suspect but instead of messing with that I tried the service key and that wasn't working either so now switch and timer eliminated. Swapped the contactor and back in business. You could also short the motor starter wire if you didn't have a service key. Anyway, what I'm getting at is if you swapped the contactor with a spare off the bat you could be up and running and making money, and can play around with the wonky one on the bench if you desired.