HOt tub will not heat, maintaining 94

[Iowa]

heater is heating, pumps working but hot tub wont heat past 94 at this point , it maintains 94 but wont heat beyond that. 

[cranbiz]

I suspect it's a sensor. Depending on the tub, there might be two sensors . Post up pictures of the spa pack, the wiring diagram usually found on the cover and of the equipment area so we know what you have.

[CanadianSpaTech]

I suspect that it is only heating on one leg of the heater and you have a bad relay on the other leg. 

[Iowa]

[RDspaguy]

When hear "only heats to 90something", I assume the heater is not working at all and the pumps are keeping it warm. 

Do you have a multimeter? Test voltage to heater. Test pressure switch for continuity. Test across thermo-disc for voltage. Post results.

[Iowa]

I cleaned it out , emptied it over the weekend, checked all the plumbing and refilled. temp went from 65 to 86 and stalls at 86, pressure switch is new, and tested . I am little nervous using a multimeter, but will borrow one again tomorrow and check again. Could it be the hi limit switch ? heating element is new, pressure switch is new. 

[Iowa]

Oh and does it look like the heater is wired correctly ? Also know that this all started when I emptied it , cleaned it and refilled it in the summer, has not worked right since. So I replaced the heating element and the pressure switch. Had a new shut off box installed, I am about to give up but winter almost here and I have put so much in to it, I hate to give up now.