I have a 2000 Morgan Monaco Spa Hot Tub that appears the heater is not working. I can feel the metal pipe and it is not warm. Any suggestions?? If it is the heater, do you recommend Morgan replacement parts or is their a better third party?

It's normal for the heater tube to not feel "warm". Typically the water exiting the heater will only be, maybe, 1/2 degree warmer than when entering.

I don't believe there's any parts in a Morgan spa that are Morgan "brand"... They're all generic parts available from many sources.

I know on all the tubs I have seen, you can tell no difference, on either side of the tub. I used a infrared thermometer, and the difference was less than 1 degree from the water entering to exiting the heater