B737-800
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Troubleshooting; Human-Machine Interface
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance; Inflight Event / Encounter Fuel Issue; Inflight Event / Encounter Weather / Turbulence
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Diverted
Human Factors; Procedure; Aircraft
Arriving at the aircraft during boarding; the FO advised me that he had found 'a lot of things messed up' in the cockpit and that the aircraft (which we ourselves had flown in the night before) had obviously been seen by maintenance overnight. On pushback; I noted a large number of aircraft awaiting takeoff clearance; and so I told the FO to plan a single-engine taxi-out until the lineup for takeoff was shorter; which we did. We started the #1 engine roughly 5 minutes before takeoff; and I believe we accomplished all taxi and before takeoff checks in an unhurried manner and pace; with nothing abnormal to note. I specifically remember seeing the ELEC legend on my '6-pack' of annunciators remain illuminated before we commenced single-engine taxi; and noted that this was normal for single-engine operation; but I do not recall seeing any lights on the FO's 'six-pack.'Climbing through roughly FL250 on departure from ZZZ; I saw we'd have to climb through a thin layer of cloud and the SAT was below 10; so I reached up to activate the engine anti-ice. As I did so; I noted three annunciators illuminated for the FO's pitot; AOA vane; and elevator feel anti-ice; for all of which the switch was already in the ON position; and I believe I heard an audible 'click' at the same time. I called the FO's attention to the annunciators; and he replied that he had not seen them illuminated before I did. I asked him to do a RECALL check of the annunciators and; doing so; the ANTI-ICE legend remained illuminated on the 'six-pack' of caution annunciators on his side. Both of us were tempted to recycle the affected pitot-heat switch to AUTO and back to ON; but I directed him to consult the QRH and complete the applicable procedure; which he did while I continued PF duties. The procedure does not call or allow for any switch or CB resets; and only informs crew that the affected components are no longer anti-iced; and to avoid icing conditions. Since we were now above at least two layers of cloud; and since our intended destination; ZZZ1; was also at or near freezing and beneath at least one layer of an overcast; I informed dispatch of the need to avoid icing and possibly divert from ZZZ1. After a considerable length of time I did not measure but which felt like roughly half an hour; Dispatch 'seemed' to direct us to divert to ZZZ2; which had few clouds; but since the distance/time involved appeared it would leave us close to critical on fuel; so I asked them to provide a fuel projection; which did not come within several minutes. At this point; both the FO and I were concerned that further hesitation could create a critical fuel situation when none might have existed absent our hesitation; so we informed ATC that we needed to divert to ZZZ2; based upon Dispatch's advice and my own projection of being able to land with just-legal reserves. At that point; dispatch sent another message which 'seemed' to change their direction for us to divert to ZZZ3; and since this was by now (being just west of ZZZ4) far closer; we informed ATC of our need to change destination again; to ZZZ3; and asked dispatch to clarify if they were officially directing us to divert or not; as their communications had seemed ambiguous to this point and seemed to leave the debate/question unresolved. We did receive a  clarification soon thereafter; however; and diverted to ZZZ3 uneventfully; avoiding not only all icing; but all visible moisture.Once at ZZZ3; contract maintenance came aboard and; upon direction from [Maintenance Control]; checked the CB's; finding a total of 4 (four) popped behind the captain's seat. 3 corresponded to the 3 annunciator lights which had illuminated on the overhead anti-ice panel; and the fourth was for HF radio #2; which we had not attempted to use. Seeing those breakers popped; hearing from the tech on the phone that the fact that a fourth anti-ice equipment control breaker was NOT popped while the other 3 were was extremely unlikely; and knowing from my review of the AML that the crew oxygen had been serviced the night before; I began to question whether they had in fact popped in the climb after takeoff; as I had perceived; or if they had been popped the night before; with the annunciators just not getting our attention before that; as adherence to pre-taxi/taxi and before takeoff checklists should have provided; via the RECALL function. Contract maintenance reset all the breakers; directed us to run the #2 engine with the anti-ice first OFF; then ON; then OFF again; noted normal operation of everything; and sent us on to ZZZ1.This event occurred because EITHER: 1) both one or more mechanics AND two pilots did not adhere to good practices and/or written procedures; causing a) circuit breakers pulled as part of a maintenance function not to get reset; b) the breakers pulled to escape both pilots' attentions during preflight; and c) the flight crew to remain ignorant of the inoperative status of the equipment affected by the breakers because of their failure to adhere to procedures developed to direct their attention to such a problem before takeoff (RECALL check's completion AFTER the second engine start); OR 2) the circuit breakers for the three pitot/AOA vane/elevator feel pitots found popped after shutdown all popped in flight by some cause that could not be duplicated; and the failure of those heaters did not; either by design or because of some other failure; cause a MASTER CAUTION alert to the crew.Mechanics should; if they don't already; follow a checklist for the restoration of any/all equipment and controls they deactivate/operate in the course of their duties; particularly those deactivated by pulling circuit breakers. Perhaps a 'maintenance in progress' sign on the pedestal or similarly prominent location; which is not to be removed until they ascertain restoration of all such equipment; would be a helpful memory aid. For pilots; single-engine taxi is practiced so rarely that; any time it is practiced; pilots' attention; reference; and faithfulness to the written checklist must be redoubled/maximized to ensure that the monitors and checks normally done before taxi are not omitted or 'completed' prematurely; rendering them invalid.
B737-800 Captain reported multiple popped circuit breakers were discovered during flight in addition to anomalies with the anti/de-icing system that required a diversion.