derek500 Posted October 30, 2021 Share Posted October 30, 2021 A couple of weeks ago I descaled my Truma. When I went to turn it on nothing happened. Did the usual checking of fuses etc. and found no problems. After a few goes it suddenly decided to work and I had heating/hot water functioning perfectly. Yesterday, I put it on again, but nothing. Checked fuses etc. Pressed the 'hidden' reset button and multimetered the 12v connection on the boiler and all fine. The water and space lights on the Sargent are both illuminated. I don't have a digital control panel, just the two rotary switches and there are no error lights and I can't see any flashing red lights on the PCB (on the side of the sockets with the Union Jack I believe). Is there a way to test the rotary switches, as one of those may be the problem? Any other suggestions? Thanks Link to comment Share on other sites More sharing options...
thebishbus Posted October 31, 2021 Share Posted October 31, 2021 No suggestions really . Was it working normally before you descaled it ? How did you descale it ? Could you have disturbed something in that process.?. Brian B. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 31, 2021 Share Posted October 31, 2021 derek500 - 2021-10-30 1:40 PM ...Is there a way to test the rotary switches, as one of those may be the problem? Any other suggestions? Thanks This ebay advert is for a pair of Combi ‘E’ control dials https://tinyurl.com/ncs7sba9 One of the photos shows the rear of both dials (copy attached below) and it will be seen that one dial has a single socket-connection and the other dial has two sockets. If you believe the control dials might be the cause of the problem, you could remove the dials from wherever they are mounted in your motorhome, disconnect the cable-plugs from their sockets and then reconnect them making sure they are firmly in place. As far as I can see, that’s the best you could do. It MIGHT be possible for Truma(UK) to test the dials, either by using specialised equipment or by connecting the dials to a ‘workbench’ Combi E that’s known to be working properly, but neither of those options will be available to a motorhome owner. It sounds like you know about ‘hard resetting’ a Combi (there are YouTube videos about this) but if the appliance is showing absolutely no life at the main PCB or control dials and you’ve confirmed that 12V power is present at the heater, I don’t know what you can do next. Link to comment Share on other sites More sharing options...
buddy Posted October 31, 2021 Share Posted October 31, 2021 When you have checked the fuses did this include the ones under the cover on the unit ? Link to comment Share on other sites More sharing options...
derek500 Posted October 31, 2021 Author Share Posted October 31, 2021 buddy - 2021-10-31 12:41 PM When you have checked the fuses did this include the ones under the cover on the unit ? On the boiler itself I just checked the small striped fuse under the top cover. The fact it was not working, working and not working again, leads me to believe it's not the fuses. Link to comment Share on other sites More sharing options...
buddy Posted November 1, 2021 Share Posted November 1, 2021 I believe that the control takes its power from the boiler , it could be worth double checking that connection at the boiler in case it is loose / damaged Link to comment Share on other sites More sharing options...
derek500 Posted November 1, 2021 Author Share Posted November 1, 2021 buddy - 2021-11-01 9:15 AM I believe that the control takes its power from the boiler , it could be worth double checking that connection at the boiler in case it is loose / damaged Thanks for that. Checked all visible connections, they seem OK. I assume the ethernet/telephone type plug that connects on the left hand socket with the Union Jack sticker is the controller? One other thing. There's no water in the boiler, but the manual says it doesn't need it to work in heating only mode. That shouldn't affect it not starting, should it? Link to comment Share on other sites More sharing options...
Robinhood Posted November 1, 2021 Share Posted November 1, 2021 ...just a quick check; are you testing on gas or mains?... If mains, there is a second 240V fuse hidden well away which is a known failure point (the unit will, however, continue to function on gas, even if this fuse has blown). The intermittent working doesn't really resonate with that, but it is worth the question. Edited to add: In the case of failure of the 230V fuse, I'd expect some indication at the controls, but these units are sometimes unpredictable. Link to comment Share on other sites More sharing options...
buddy Posted November 1, 2021 Share Posted November 1, 2021 The Combi does not need water in the boiler to work , they can be run , for heating only , when empty. The Ethernet type connections that you have checked are the correct ones but it may be worth removing and replacing them , if you have not done already , in case there is a poor connection. It would also be worth trying the same at the control end of things in case the problem is there, the same type of connectors are used , the controls can be removed if you unclip the plastic cover and undo the fixing screws behind it . Link to comment Share on other sites More sharing options...
derek500 Posted November 1, 2021 Author Share Posted November 1, 2021 Solved!!! I filled the boiler with water. Perhaps it triggered a sensor, but why does it say heating works without water in the system? Sorry to waste your time. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 1, 2021 Share Posted November 1, 2021 When put into HEATING MODE (that’s blown-air heating mode) a Combi (E) can be run with its water container empty. When put into HOT WATER MODE (ie. when blown-air heating is NOT required) a Combi (E)’s water container should be filled. The latter requirement is stated in the Combi (E) operating instructions in the section shown below. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.