Original diagnosis by Pure Water (PW) technician was heater tripping breaker. PW ordered and installed new heater. Breaker did not trip immediately post installation of new heater but continued to trip within hours of switching on. Technician returned and after manually switching the breaker off and on several times, he recommended breaker be replaced. Technician did not have an ammeter and could not confirm what was causing the breaker to trip. PW charged me $170 even though technician did not have proper equipment for the diagnosis he made.
I purchased a new Square D 40 Amp, 240V, GFI breaker for the tidy sum of $325 (inl. HST). The breaker was installed. Spa water was topped up. Breaker switched on; overnight the breaker tripped again.
At this point I had not paid the $170. Upon calling PW to describe the situation, and to request a technician with an ammeter, I was told that PW would not send a technician until I paid the outstanding $170 for the previous visit (during which the technician, without an ammeter, made the diagnosis that the breaker was faulty and recommended I replace it.)
So now we're at the juncture where having already provided $470.00 to PW for parts (new heater) and services (diagnosis, installation of new heater), the problem persists, yet PW will not return unless I pay for their most recent misdiagnosis of a faulty breaker.
Not exactly the level of commitment to quality and customer satisfaction that I had expected.
UPDATE: Competitive company diagnosed the problem to be a blower; repair was made and spa working fine. So the question remains whether the heater was bad in the first place; c'est la vie.