blackrose Posted October 14, 2021 Report Share Posted October 14, 2021 (edited) Well I took a chance on a reconditioned Webasto Thermotop C from ebay and the unit is very noisy. It's like a high pitched buzz. It settles down and it's much quieter after about an hour of running and then the noise is fine inside the boat and outside. It came with a 3 month warranty but I bought the thing about 18 months ago and have only just got around to fitting it so the warranty is void. I'm not even sure the seller is still on ebay. All the rads get nice and hot as does the Kuranda fan heater which I fitted to the calorifier loop, so in terms of heating it's all working really well. I didn't fit the exhaust silencer but the exhaust note isn't noisy, it's just the quiet jet engine whoosh. The excessive noise is coming from the burner unit itself and it's worst inside the boat. A different ebay reconditioner told me it might be the combustion fan that needs replacing, so it looks like my gamble on a cheap unit didn't pay off. What's my best option, rip it out and get it fixed or shell out for another reconditioned unit? I can't live with the first hour of noise on startup. Edited October 14, 2021 by blackrose Link to comment Share on other sites More sharing options...
davidb Posted October 14, 2021 Report Share Posted October 14, 2021 Have you got an intake silencer on it? That might help. Link to comment Share on other sites More sharing options...
blackrose Posted October 14, 2021 Author Report Share Posted October 14, 2021 (edited) Yes it has the air intake silencer fitted. I said it quietened down after an hour, but it's just cycled up again and the noise is ridiculous. Been running for about 90 mins this morning. Should I try to get hold of a diagnostics until to see if there's a fault code? Edited October 14, 2021 by blackrose Link to comment Share on other sites More sharing options...
GUMPY Posted October 14, 2021 Report Share Posted October 14, 2021 Try the exhaust silencer, you have nothing to lose, back pressure may just make it quieter😉 Link to comment Share on other sites More sharing options...
blackrose Posted October 14, 2021 Author Report Share Posted October 14, 2021 Yes ok I'll try that. Link to comment Share on other sites More sharing options...
Cas446 Posted October 15, 2021 Report Share Posted October 15, 2021 On 14/10/2021 at 13:29, blackrose said: Yes ok I'll try that. The webasto reconditioners sometimes crank up the CO2 adjustment setting. They do this to ensure that the unit does not coke up, as they have no idea what exhaust you are going to fit to it. The result is a very noisy unit that runs inefficiently - but it will run through their 'warranty'. So if the fan is just running very fast as opposed to being knackered using the software may help, as you can adjust the setting, but it's trial and error, and you may have a knackered fan. Link to comment Share on other sites More sharing options...
Bee Posted October 15, 2021 Report Share Posted October 15, 2021 Had an Eberspacher that was noisy, turned out to be the motor bearing at the fan end. I didn't take it apart, it was in a library van so fixing stuff was not my job thank goodness. Link to comment Share on other sites More sharing options...
blackrose Posted October 17, 2021 Author Report Share Posted October 17, 2021 (edited) On 15/10/2021 at 20:38, Cas446 said: The webasto reconditioners sometimes crank up the CO2 adjustment setting. They do this to ensure that the unit does not coke up, as they have no idea what exhaust you are going to fit to it. The result is a very noisy unit that runs inefficiently - but it will run through their 'warranty'. So if the fan is just running very fast as opposed to being knackered using the software may help, as you can adjust the setting, but it's trial and error, and you may have a knackered fan. Thanks, it's definitely not an exhaust silencer/back pressure issue. I was wondering if using the wrong diameter fuel pipe might cause problems? The kit came with the recommended 2mm ID thin wall flexible fuel pipe but I used some proper 3.5mm ID marine fuel hose which was marked with the relevant ISO/Lloyds marine certification because I wasn't sure if the Webasto stuff would pass the BSS. Could using increased diameter fuel hose cause the webasto to misbehave? I think I'll try changing it for the Webasto pipe before doing anything else. How does one adjust the fan setting? Edit: Just read on an old thread that the Webasto plastic fuel pipe won't pass the BSS so I won't change it after all unless anyone knows of a compliant 2mm ID flexible fuel pipe? Edited October 17, 2021 by blackrose Link to comment Share on other sites More sharing options...
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