iQ2020 no lights at all

[2002sheds]

Hi,
     I just acquired our first hot tub, a 2001 Hot Spring Vanguard, which is in need of work. The previous owner was pretty straightforward about the issues, but was unsure of what was actually required to get the tub back into action.
     As he described it, one (he didn't remember which) of the breakers in the sub panel started to trip every once in a while, then it became more frequent, and finally, both breakers tripped and, upon resetting, no anything... none of the lights on the motherboard light up.
     Along the way, the Heater Relay as been replaced, once pretty recently (so it is the newer, more robust relay), the main Circuit board(at east once, also not a real long time ago), and he said he replaced the heater at least once.
     So far, I have:
*verified that the wiring is correct
*verified that the GFCI breakers are functioning
*verified voltage to the heater relay
*verified that voltage is making it to the black tab and red tab on the heater relay
*verified voltage to the red tab and black tab on the motherboard.
*visually inspected both the heater relay and motherboard. The heater relay looked brand new -- no scorch marks anywhere.
   The motherboard also looked to be in good condition, with no scorching anywhere on the back, no soot, etc.  I did notice that a small chip in the middle looked like it might have gotten hot. The telephone style plug for the ozonator also looked a little fried, and pieces of it came off when I pulled it out. And the yellow "block" towards the upper left looked like it may have gotten hot, but it was not melted...
     Other than that, I am stumped. Is there a way to verify whether or not the motherboard is fried?
     Any help will be greatly appreciated!

Thanks,
David

[Chas]

Disconnect the heater from the spa. You can leave the ground wire, but undo the black and white wires. Try the breakers. If they no longer trip, then the heater is the culprit. Usually, the heater will only trip the 30A breaker, but if it becomes grounded badly enough, it can trip both breakers.

Also, I read your statement that it is wired correctly, but so many times I find that the neutral wire from the spa gets landed on the neutral bus inside the sub panel, and not on the 20A breaker as it is supposed to be.

HTH

 

[2002sheds]

Hi Chas,
     Thanks for the reply!  The heater wires were disconnected (and still is) before I tried any other test, so we can rule that out.
     And the neutral wire does go from the 20 amp GFCI breaker to the correct terminal on the heater relay board, so I feel pretty safe in ruling that out as well...
     Are there other points on the motherboard that I should verify voltage? As I said in my original post, I am getting 110 to the tab marked "red" and to the tab marked "black"


Thanks,
David

[2002sheds]

Hi,
     So I replaced the motherboard, and now the tub is coming to life. The recirc pump is definitely on and pushing some water out. The control panel shows the different functions. I can get the jets to work some of the time if I press the Jet switch just right (the buttons look kind of distorted), and the jets come on when I press Clean.
     So far, no sign of life from the heater. I cannot tell if any water is being pushed through the vinyl tubing. part of the reason for this is the calcium or rust that has built Up on the tube. This is my first tub, so my questions are, I'm sure, pretty basic...
     The LIM OK and Heater lights are on on the motherboard, as is a tiny red LED at D17.

     I verify voltage to the heater relay. I haven't yet checked the red and black tabs on the motherboard. What else should I check? According to the previous owner, the heater had been working. He has been very straightforward on everything else, soo have no reason to doubt him.

Thanks,
David