I have a LA Spas Quest 7000 spa (mfg 1995 I think, we bought new in 1996).

After draining,cleaning, and refilling awhile ago, when I tried to turn the spa on, the GFCI tripped. I couldn't get the spa to power on.
I was able to phone a Maddox service rep, and he had me unplug a 3 wire connector that I think powers the heater. Anyway, when I unplug that 3 pin connection, the spa will power on. He indicated that this meant either the heater or heater elment is causing the problem.
He said replacing the whole heater is easier, but replacing just the element is cheaper.
I'm ok with replacing the heater. I think it's a flow-through. I attached a pic of the mechanical area.
So, can this be a do-it-yourself job?
Is replacing the heater a wise choice given the spas age (it's always been indoors)?
Any tips for replacing a heater, or do the heaters generally come with instructions for installation?
Are there different brand of heaters I should look at, or should I use Maddox (I don't think LA uses them anymore).

Thanks in advance for any tips/advice,
Gary

Those heaters are one of the easiest to replace. The hardest part about your installation is getting to it, as it's behind the spa pack. Remove the assembly before forking out money for a new one. Many aftermarket flowthrough heaters will fit right in and may be a lot cheaper. The old one will have the wattage rating on the housing. All you have to do to remove it is unhook the wires, loosten the two big black nuts, and it just pops right out. They usually have detailed instructions on how to change out. If you opt to replace just the element, all you need to do besides the above is remove the two large nuts the wires attached to, and the element slips right out. This option is a lot cheaper, but you will want to make sure you get the correct offest.

If you do replace the whole unit, I will gladly pay shipping and a little extra for your time for your old unit.