Narrative:

Flight attendant's call at 2000 ft during climb. Right aft lavatory was flushing continuously. Flight attendant (flight attendant) who reported this; mentioned she had seen this before and that they had done an inflight turnback. Contacted maintenance control and accessed system handbook. Asked flight attendant to turn (move) water supply to 'faucets only'. When the flight attendant moved the supply to 'faucets only'; the flushing stopped. The nextgen system manual page 1.030/43 mentions an electric vacuum pump. My concern was that the pump might continue to run. Maintenance control said that there was no pump. That this system was different than the B737-400 as it was a vacuum system that involved a compressor. This created confusion because what they were telling us was in conflict with our systems handbook information. Maintenance control said that as long as the flushing had stopped and we were having no pressurization problems we were ok to continue. We leveled at 28;000 as a precaution; after hearing about the pressurization. I asked maintenance control if they could assure me that a pump was not running and their response was that 'this was a vacuum system; there was no electric pump; and they could assure me of nothing since they were in an office and we were at 30;000 feet'. I was taken aback at this summary. We continued to communicate with the flight attendant. She turned the supply water back to 'on' and the lav started flushing again. We had her turn the supply valve back to 'faucets only'. The flushing stopped again. We were level at 28;000. We contacted maintenance control and again reported the problem. The response was that as long as no flushing was occurring and no pressurization problems were present we should be ok to continue. Maintenance control then mentioned a handle at the base of the toilet bowl that they wanted pulled or pushed to deactivate the toilet. Maintenance control could not remember if the handle was to be pushed or pulled. There is no guidance in our systems manual concerning this handle. Maintenance control advised that the shroud around the bowl needed to be pulled away to access the handle. We directed the flight attendant to remove the shroud and pull the handle. After the shroud was removed; the flight attendant donned some gloves but could not locate the handle. Around this time we lost contact with maintenance control due to the ZZZ remote being out of service. We were not able to talk with maintenance control or dispatch. Upon reestablishing contact with maintenance control; I had decided to send the first officer back to make sure the valve under the toilet bowl had been pulled. Told dispatch of my intentions. Dispatch then notified us that a DH captain was riding in back. I asked him to come to the cockpit and to go to the lav and pull the handle to deactivate the toilet. He went back; pulled the handle; turned the water on for some reason and flushed the toilet. We had asked him to pull the handle only. He reported what he had done to me. I asked him to put the supply handle back to the 'faucets only' position and secure the lav door so it could not be used. We then felt that we had done as much as we could. Though we were never absolutely sure that the electric vacuum pump was off. We continued to ZZZ2. The completion of all of the above took us all the way to 80 southeast of ZZZ1. After landing the flight attendant's reported that the lav had started flushing again during the descent. We theorized that this probably began at 16;000. The lav was of course written up. The mechanic that met the aircraft was very familiar with the nextgen lav system. He concurred with our system manual; that there was in fact an electric vacuum motor that operated below 16;000ft. He completely understood our concern about the motor continuing to run. In two minutes of talking with him we were able to communicate to him what we were unable to communicate to maintenance control in flight. Maintenance control put the lav on MEL and deactivated it.during climb out of ZZZ2; in the same aircraft on our return to ZZZ; the most forward; aft left lav; flushed by itself four times as reported by the flight attendant's. I contacted maintenance control again by radio. Maintenance control did not know of any prior problems with our aircraft and stated they had not had any tie in with the prior maintenance controller when they came on duty concerning our aircraft. Upon my bringing them up to date the maintenance controller stated it was our decision as to how to proceed. We continued to ZZZ2 since the flushing had stopped with no intervention on the flight attendant's part and was operating normally now.I believe the above event reveals a few systemic problems with our operation. 1. Maintenance control; upon our first contact with them on climb out from ZZZ assessed our problem and focused on a 'vacuum and compressor system' that was 'completely different from the B737-400'. They were not listening to our concern about the electric motor for vacuum mentioned in our system handbook 1.030 page 43. When we asked them to take a look at that page; they obviously did not look at the page because they kept talking about a compressor driven vacuum. A quick review of that page after we mentioned it to them would have gone a long way toward clarifying our concern. 2. When I asked if maintenance control could assure us that the electric pump was not continuing to run; the comment (was) made that; 'I can't assure you of that; I'm in an office and you are at 30;000 feet' was uncalled for and very unprofessional. Why should a flight crew ever be in a position of having to argue with maintenance control about a system clearly described in our manuals? Our entire operation should be based upon supporting the ones who are at '30;000 feet'; not being agitated by their problems. We look to maintenance for guidance occasionally. In this case they provided very little information; but what they did provide was in conflict with our system handbook. The manner and tone of their communication with us did little but exasperate our problem. 3. Increased guidance in the system handbook concerning the lav system and a way to shut off the electric vacuum pump motor would be helpful. 4. The inoperative remote at ZZZ3 was also a factor in this event. Alternate communication options would have been helpful. In retrospect; the remote at ZZZ4 could have been used by dispatch calling us through it; if I understand the current field and facilities note correctly. Of course ACARS was used; but it was cumbersome.

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Original NASA ASRS Text

Title: A Captain reports about lack of support and unprofessional behavior from their Maintenance Controllers during flight; when they were trying to resolve a continuous flushing Aft lavatory that affected cabin pressurization.

Narrative: Flight Attendant's call at 2000 FT during climb. Right Aft lavatory was flushing continuously. Flight Attendant (FA) who reported this; mentioned she had seen this before and that they had done an inflight turnback. Contacted Maintenance Control and accessed System Handbook. Asked FA to turn (move) water supply to 'Faucets Only'. When the FA moved the supply to 'Faucets Only'; the flushing stopped. The NextGen System Manual page 1.030/43 mentions an electric vacuum pump. My concern was that the pump might continue to run. Maintenance Control said that there was no pump. That this system was different than the B737-400 as it was a vacuum system that involved a compressor. This created confusion because what they were telling us was in conflict with our Systems Handbook information. Maintenance Control said that as long as the flushing had stopped and we were having no pressurization problems we were OK to continue. We leveled at 28;000 as a precaution; after hearing about the pressurization. I asked Maintenance Control if they could assure me that a pump was not running and their response was that 'this was a vacuum system; there was no electric pump; and they could assure me of nothing since they were in an office and we were at 30;000 feet'. I was taken aback at this summary. We continued to communicate with the FA. She turned the supply water back to 'On' and the lav started flushing again. We had her turn the supply valve back to 'Faucets Only'. The flushing stopped again. We were level at 28;000. We contacted Maintenance Control and again reported the problem. The response was that as long as no flushing was occurring and no pressurization problems were present we should be OK to continue. Maintenance Control then mentioned a handle at the base of the toilet bowl that they wanted pulled or pushed to deactivate the toilet. Maintenance Control could not remember if the handle was to be pushed or pulled. There is no guidance in our Systems Manual concerning this handle. Maintenance Control advised that the shroud around the bowl needed to be pulled away to access the handle. We directed the FA to remove the shroud and pull the handle. After the shroud was removed; the FA donned some gloves but could not locate the handle. Around this time we lost contact with Maintenance Control due to the ZZZ remote being out of service. We were not able to talk with Maintenance Control or Dispatch. Upon reestablishing contact with Maintenance Control; I had decided to send the First Officer back to make sure the valve under the toilet bowl had been pulled. Told Dispatch of my intentions. Dispatch then notified us that a DH Captain was riding in back. I asked him to come to the Cockpit and to go to the lav and pull the handle to deactivate the toilet. He went back; pulled the handle; turned the water on for some reason and flushed the toilet. We had asked him to pull the handle only. He reported what he had done to me. I asked him to put the supply handle back to the 'Faucets Only' position and secure the lav door so it could not be used. We then felt that we had done as much as we could. Though we were never absolutely sure that the electric vacuum pump was off. We continued to ZZZ2. The completion of all of the above took us all the way to 80 SE of ZZZ1. After landing the FA's reported that the lav had started flushing again during the descent. We theorized that this probably began at 16;000. The lav was of course written up. The Mechanic that met the aircraft was very familiar with the NextGen lav system. He concurred with our System Manual; that there was in fact an electric vacuum motor that operated below 16;000ft. He completely understood our concern about the motor continuing to run. In two minutes of talking with him we were able to communicate to him what we were unable to communicate to Maintenance Control in flight. Maintenance Control put the lav on MEL and deactivated it.During climb out of ZZZ2; in the same aircraft on our return to ZZZ; the most Forward; Aft left lav; flushed by itself four times as reported by the FA's. I contacted Maintenance Control again by radio. Maintenance Control did not know of any prior problems with our aircraft and stated they had not had any tie in with the prior Maintenance Controller when they came on duty concerning our aircraft. Upon my bringing them up to date the Maintenance Controller stated it was our decision as to how to proceed. We continued to ZZZ2 since the flushing had stopped with no intervention on the FA's part and was operating normally now.I believe the above event reveals a few systemic problems with our operation. 1. Maintenance Control; upon our first contact with them on climb out from ZZZ assessed our problem and focused on a 'vacuum and compressor system' that was 'completely different from the B737-400'. They were not listening to our concern about the electric motor for vacuum mentioned in our System Handbook 1.030 page 43. When we asked them to take a look at that page; they obviously did not look at the page because they kept talking about a compressor driven vacuum. A quick review of that page after we mentioned it to them would have gone a long way toward clarifying our concern. 2. When I asked if Maintenance Control could assure us that the electric pump was not continuing to run; the comment (was) made that; 'I can't assure you of that; I'm in an office and you are at 30;000 feet' was uncalled for and very unprofessional. Why should a flight crew ever be in a position of having to argue with Maintenance Control about a system clearly described in our Manuals? Our entire operation should be based upon supporting the ones who are at '30;000 feet'; not being agitated by their problems. We look to Maintenance for guidance occasionally. In this case they provided very little information; but what they did provide was in conflict with our System Handbook. The manner and tone of their communication with us did little but exasperate our problem. 3. Increased guidance in the system handbook concerning the lav system and a way to shut off the electric vacuum pump motor would be helpful. 4. The inoperative remote at ZZZ3 was also a factor in this event. Alternate communication options would have been helpful. In retrospect; the remote at ZZZ4 could have been used by Dispatch calling us through it; if I understand the current field and facilities note correctly. Of course ACARS was used; but it was cumbersome.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.