Hot Tub Heater Shutdown

hot-tub

My hot tub shuts down with error code "dr" which my manual says is:

Possible inadequate water, poor flow, or air bubbles in detected in
heater. Spa is shut down for 15 minutes.

The sequence of events is:

  1. jets turn on and flow is good.
  2. about a minute later bubbler turns on.
  3. about 5 seconds later the heater turns on.
  4. about 3 seconds later the tubs shuts down with error code "dr"

I was just restarting the tub and there was rainwater that had gotten dirty so I figured there was crap in the heater so I opened up the pipe and looked in. It seems surprisingly clean.

What else can I check before I call a pro?

Should I just keep trying it to see if it will eventually work itself out?

Best Answer

I further disassembled the heater and found a check valve flapper stuck in the heater coils.

I then realized that I had broken the check valve in the filter housing while vacuuming the water out of the pipes.