Spa high speed pump does not produce full stream without help

[gkran]

Our spa cascades into the pool, with the standard setup up sharing the main pump and filter and the spa having an additional spa pump for the jets.

We hadn't used the spa for a few months, and now the spa pump for the jets does the following:
- when spa pump is turned on (main pump in spa mode, water hot), it does not produce a strong stream of bubbles.
- I manually primed the pump, checked the back-flow valve and even filled the intake pipe, but it did not help.
- One day someone inadvertently turned on the spa pump once (don't know how long, doubt the main pump was in spa mode) and the spa pump was producing the normal high pressure bubbles.
- If we get in the spa and block and quickly release one of the jets a few times, it gurgles and eventually produces the normal high pressure bubbles.
- One of the floor jets does not produce many bubbles, even when the high pressure stream is working (it has worked in the past).

Any ideas where to start? O-rings. pool pump, spa pump, blocked pipe?

 

[mas985]

Do you remember what the filter pressure was when it was working correctly vs now? The symptoms sound like a partial blockage in either the water lines or air lines. You can first try a filter cleaning/backwash to eliminate that.

 

[gkran]

I backwashed the day before our last usage. I think the pressure was at 8.

I have time over the holidays to trouble shoot this, any suggestions or tests are welcome.

 

[mas985]

8 psi is a little low for a spa so it could be a clogged impeller or suction line. Check the pump basket and impeller inlet for debris.

Also make sure you have the proper return side valves set.