I saw another forum post but I can't find it now.
I have a Blue Ridge spa, Model (on the control unit thing) is 600-66.

First off, i apologize if my terminology is incorrect, I've always been IN the spa, not under it!

My situation now is the thing wont heat. I've tried a few things as I was told, fiddling with the thermostat, checking to see if pump is pumping.)
My pump operates in high speed and low speed just fine, water is circulating through plumbing.

From that point, I was led to a webpage which suggested a slew of things, two being pressure switch and heating coil.

Any way to test either? Or is it simpler just to go ahead and replace both?
We've had this hot tub since it was new (bought in 1995) and have NEVER had to replace anything (except a month after we got it, they replaced the motor under warranty) but it's been running like a champ since we bought it new with nothing gone wrong until now.

I'm figuring replace them both, since it's been a while... Any comments? Suggestions?

Thanks a bunch!!
Christopher.

As old is the pressure is I would replace it, they are a wear item in a spa.

For the heater you will need to check to see if you are getting proper voltage to it, if you are then do an amp draw check, if it is drawing the correct amps it is good. If you have voltage and no amperage it is bad.

Heater wattage divided by voltage will give you the correct amp draw.

If no voltage your problem is elsewhere i.e. thermostat, pressure switch, relay/contactor...