Guest Mike M Posted February 19, 2022 Share Posted February 19, 2022 My heater element run for about 10 second and off and on fan runs all the time any guess thanks mike Link to comment Share on other sites More sharing options...
DavidL Posted February 19, 2022 Share Posted February 19, 2022 How about what make / model the heater is, and some history. And a clear description of the problem. ie: help us help you. Link to comment Share on other sites More sharing options...
Guest Mike M Posted February 19, 2022 Share Posted February 19, 2022 Cargo heater 3000RV in a 04 Knight Link to comment Share on other sites More sharing options...
DavidL Posted February 19, 2022 Share Posted February 19, 2022 and what troubleshooting have you done already? And what is it not doing correctly? And when did that start happening? And did something happen that caused that? if you can't provide information that is required for assistance, no one can help 1 Link to comment Share on other sites More sharing options...
cbr046 Posted February 19, 2022 Share Posted February 19, 2022 The thermal fuse inside the wet bay heater gives out. This is the fuse (and crimps) from Newark Electronics - I bought 3 sets and gone through 2 of them. The fuse isn't robust enough (300W = 25A) and haven't found a more robust one so I'll probably knock it down with a 0.1 ohm resistor from my junk box at home in series with the main supply line. It could also be tripping on temp (184C) . . . . Line No:1 Stock No: Manufacturer Part No: UOM: Quantity: Price: Extended Price: 39T4439 G5A01184C Each 1 3 $2.54 $7.62 Customer Part Number: Customer PO Line Number: 001 Description: FUSE, THERMAL, 184øC, 20A, 250VAC; Product Range:MICROTEMP Series; Fuse Current:20A; Voltage Rating VAC:250V; Functioning Temperature:184øC; Fuse Terminals:Axial Leaded; Holding Temperature:169øC Shipping Via: GROUND FOBS Expected Ship Date: 04/07/2021 Expected Ship Quantity: 3 Line No:2 Stock No: Manufacturer Part No: UOM: Quantity: Price: Extended Price: 50F3313 323754 Each 1 6 $0.61 $3.66 Customer Part Number: Customer PO Line Number: 002 Description: TERMINAL, PARALLEL SPLICE, CRIMP; Product Range:SOLISTRAND, STRATO-THERM Series; Wire Size AWG Min:12AWG; Wire Size AWG Max:10AWG; Conductor Area CSA:6.64mmý; Terminal Material:Copper; Insulation:Non Insulated Link to comment Share on other sites More sharing options...
JDCrow Posted February 19, 2022 Share Posted February 19, 2022 3 minutes ago, cbr046 said: The thermal fuse inside the wet bay heater gives out. This is the fuse (and crimps) from Newark Electronics - I bought 3 sets and gone through 2 of them. The fuse isn't robust enough (300W = 25A) and haven't found a more robust one so I'll probably knock it down with a 0.1 ohm resistor from my junk box at home in series with the main supply line. It could also be tripping on temp (184C) . . . . Line No:1 Stock No: Manufacturer Part No: UOM: Quantity: Price: Extended Price: 39T4439 G5A01184C Each 1 3 $2.54 $7.62 Customer Part Number: Customer PO Line Number: 001 Description: FUSE, THERMAL, 184øC, 20A, 250VAC; Product Range:MICROTEMP Series; Fuse Current:20A; Voltage Rating VAC:250V; Functioning Temperature:184øC; Fuse Terminals:Axial Leaded; Holding Temperature:169øC Shipping Via: GROUND FOBS Expected Ship Date: 04/07/2021 Expected Ship Quantity: 3 Line No:2 Stock No: Manufacturer Part No: UOM: Quantity: Price: Extended Price: 50F3313 323754 Each 1 6 $0.61 $3.66 Customer Part Number: Customer PO Line Number: 002 Description: TERMINAL, PARALLEL SPLICE, CRIMP; Product Range:SOLISTRAND, STRATO-THERM Series; Wire Size AWG Min:12AWG; Wire Size AWG Max:10AWG; Conductor Area CSA:6.64mmý; Terminal Material:Copper; Insulation:Non Insulated Awesome info! Thanks Link to comment Share on other sites More sharing options...
DavidL Posted February 19, 2022 Share Posted February 19, 2022 Link to comment Share on other sites More sharing options...
Gary M Posted February 19, 2022 Share Posted February 19, 2022 There is a write up in our files. Link to comment Share on other sites More sharing options...
jacwjames Posted February 20, 2022 Share Posted February 20, 2022 I would have thought if it was the thermal fuse the heater would not work at all. I wonder if it has some sort of setting for heater and one for fan that allows the fan to stay on all the time and the element on and off as needed. Link to comment Share on other sites More sharing options...
Gary M Posted February 20, 2022 Share Posted February 20, 2022 1 hour ago, jacwjames said: I would have thought if it was the thermal fuse the heater would not work at all. I wonder if it has some sort of setting for heater and one for fan that allows the fan to stay on all the time and the element on and off as needed. Mine ran with no heat. The snap disc is what sends power to the heater once you give it power at the convenience center. So maybe its an issue. I recently replaced mine. Link to comment Share on other sites More sharing options...
cbr046 Posted February 20, 2022 Share Posted February 20, 2022 11 hours ago, jacwjames said: I would have thought if it was the thermal fuse the heater would not work at all. I wonder if it has some sort of setting for heater and one for fan that allows the fan to stay on all the time and the element on and off as needed. The thermal fuse is in series with the heating element inside the heater. It can be triggered by current (20A) or excessive heat (184C). Being a 300W heater (25A) the fuse alone is under rated. The design engineer has been berated, flogged and cast into the Sea of Electrons. I could never find a higher rated fuse at that temp. I found a 0.1 ohm 10W resistor in my junk box from 1975 to put in series with the main supply, or with the element inside with my last fuse. I'm willing to sacrifice a few watts to keep my wet bay from freezing. - bob Link to comment Share on other sites More sharing options...
jacwjames Posted February 20, 2022 Share Posted February 20, 2022 2 hours ago, cbr046 said: The thermal fuse is in series with the heating element inside the heater. It can be triggered by current (20A) or excessive heat (184C). Being a 300W heater (25A) the fuse alone is under rated. The design engineer has been berated, flogged and cast into the Sea of Electrons. I could never find a higher rated fuse at that temp. I found a 0.1 ohm 10W resistor in my junk box from 1975 to put in series with the main supply, or with the element inside with my last fuse. I'm willing to sacrifice a few watts to keep my wet bay from freezing. - bob So the thermal fuse resets itself and the heater starts working again while the fan continues to work, is this correct? Link to comment Share on other sites More sharing options...
cbr046 Posted February 20, 2022 Share Posted February 20, 2022 7 hours ago, jacwjames said: So the thermal fuse resets itself and the heater starts working again while the fan continues to work, is this correct? I could be wrong but I don't the thermal fuse resets. One shot only. . . . . The fan works independently of the fuse. The thermal fuse affects the heating element only. - bob Link to comment Share on other sites More sharing options...
jacwjames Posted February 21, 2022 Share Posted February 21, 2022 2 hours ago, cbr046 said: I could be wrong but I don't the thermal fuse resets. One shot only. . . . . The fan works independently of the fuse. The thermal fuse affects the heating element only. - bob That's why the symptoms are so confusing. He indicates the heat comes and goes. Link to comment Share on other sites More sharing options...
Bill R Posted February 21, 2022 Share Posted February 21, 2022 11 hours ago, jacwjames said: That's why the symptoms are so confusing. He indicates the heat comes and goes. I believe there can be two issues. The bad thermal fuse will keep the element from coming on. As was the case for me. There is also what I believe is an internal temp sensor that will prevent overheating, and could go bad I suppose. This would explain heat coming on and then off. See pic below posted before in a similar post. Link to comment Share on other sites More sharing options...
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