Sorry I had to leave home this afternoon and am only not long back and seeing your reply short time ago. I will not be able to check the oven until tomorrow. But can tell you that the fan appears to be working and oven seems ok on low heat up to about 150degreesC. However once the stat control is raised to anywhere @160degrees C or above the fault kicks in and it shuts electrical supply. The main thermostat which has been replaced is apparently working ok.
I only remember seeing onE fan in my oven viz; the circulation fan when I was replacing those parts, which is inside the oven on the back wall so not sure where, or if there is a tangential fan in my model which is the Smeg SE375MFX5.
Pretty sure that there is only one fan , i.e the circulation fan which is visible inside the oven enclosure. Therefore not sure what George means when he mentions the other one viz; tangential "cooling" fan. Might add that I am also a retired electrical maintenance engineer with over forty years experience.
No George my model is about eighteen years old and has no microwave.
It just has an upper and lower heating element, grill facilty and the fan assistance which is optional depending on the mode of cooking selected.
There is as far as I can ascertain only the main thermostat and the safety (TOC) stat which is mounted on the outside upper back wall oven oven compartment. Both of these stats as I have stated have been replaced and correctly wired
Ok thanks George I will do that tomorrow and get back to you. When is a good time to get you?
Ok thanks George will check the connections on the selector switch as you have suggested and let you know if your suspicions .and diagnosis is correct. Fingers crossed, that is the problem as it is doing my head in having spent quite a few quid up to now.
Regards ***** ***** Night,
Good afternoon George,
I have now checked the selector switch which appears to be sound. There are no signs of any arcing, pitting, overheating, with all spade terminals, contacts, and wiring in perfect condition. There is also only one fan i.e the circulation fan which from what I can see is also working fine and running when oven is on.
The only other controls that I cannot be sure about is the timer control board. This also appears to be in good nick and no visible signs of burning or overheating on the components. But we never use the timer anyway as it is always on manual mode.
As stated earlier the oven seems to work ok when cooking at 150 degreesC or lower but cuts out when cooking at temperatures in excess of 160 degrees C. This could I think point back to the "new" Safety Thermostat which has just been fitted.because I can think of nothing else that would cut off the electrical supply in these circumstances. This is a real "headscratcher".
Sorry George just seen your reply and am back @oven with my phone wilmake those further checks and reply to u
George Checked as u stated from wiring diag.My apologies there is another fan located on the back outside oven wall.Have the oven on full pelt and both fans are apparently working.
Sorry that second fan which I now think is the cooling fan is fitted on to the outer skin at back of the oven.
Just a further update oven is sitting in middle of my kitchen floor withtop and back covers off exposing the wiring and componentsd
It is on and cooking up to 200degsC although main stat led still lit bit temp over 180C as led goes off when stat knob reduced to that temp.Oven still running and no cut off but was smell of burning shalac but only for a few mins...............further update.....Smell has gone but oven continued to cook and heat to setting of 200C for at least an hour with no problems. However it is sitting out of its housing on my kitchen floor with top and back covers off.
Both fans are functioning ok from what I can see and will only know if fault has disappeared temporarily until I refit all covers and refit unit into its kitchen housing which will be later when it has cooled down. However I have not actually down anything today other than shift the unit on to the floor and removed the covers to get a closer look and inspect the component parts that you suggested.
Maybe get in contact again tomorrow.
Just finished my dinner which was successfully cooked in the oven albeit located on the kitchen floor and reading your reply. Yes the burning smell which has disappeared could certainly be an indication of now perhaps "intermittent" fault as the oven continued to cook for well over an hour at high temperature which it was not doing.
My thoughts are now that one of the fan motor windings are "dodgey" and most likely the cooling one which is not visible when the oven is in situ. Although It was running the whole time that I was using it with all parts exposed. I am going to now try to meter both sets of windings to check the resistances on both, because I know both stats are new and the selector switch is just a "cam" operated device which opens and closes the various selected contacts to the heating elements.
Have had a good "sniff" around the component parts albeit with the supply switched off, but no clues as to where that smell might have emanated. Also touched around those parts which could be overheating and again no residue heat in those areas.
Got my meter and tested the resistance of the windings on the coils supplying both fans. The cooling fan showed a resistance of 131.4 ohms whilst the circulation fan windings had a 96.7 ohms resistance. I have now refitted all covers and refitted the oven into the kitchen housing. I thank you for your assistance to date even though although the fault has "disappeared" not entirely convinced that it is due to anything that I have done since you have been advising me. Perhaps you can give me advice on the expected resistance of the winding to both fans compared to my readings, as therein could be the problem.
Anyway only time will tell so may be back on tomorrow but hopefully not.
George that was all checked very carefully and all connections to recently fitted parts removed and refitted just in case there were any loose connections. As stated earlier only time will now tell ..........????
OK but in the nicest kind of way I hope not as my wife wants a new oven and I cannot afford to buy a new one right now. So fingers crossed that the oven will continue to perform as it did this afternoon for another bit longer.
Obviously you will probably not see this email until tomorrow.
As suspected the fault has reappeared on using the oven this evening. After about 20-25 mins cooking at 160C oven shut down.The oven stat LED had went out and within about 3-4mins as soon as LED reilluminatef the oven shut down.I waited until the oven came back on after about 10mins.Reset stat control to 140C but after about 10mins cooling it shut down again.Tomorrow I am going to short out the safety limit stat as I at least know the main control stat is working.This will at least enable time to cook properly until I can locate which fan is on the way out. Hope you agree.
Did not expect a reply until tomorrow u must also be a "night owl" like me. When I stated that I would be bypassing the safety limit stat this would have been only temporary and always in a controlled situation as I am well aware of the consequences of doing something stupid to carry
this out in an uncontrolled environment.
To answer your question as previously stated the oven when fumctioning full pelt Sunday afternoon was sitting on my kitchen floor with top and back covers removed and totally unenclosed.Thus it would appear to be an overheating problem when all covers fitted and fully enclosed in kitchen housing.Logistically it would appear that at least one of the fans is not functioning efficiently in an enclosed situation.
The appliance was sat on the floor of the kitchen when it functioned for over an hour at full pelt, with top and back skin enclosures also removed. .
OK and tend to agree that the cooling fan is perhaps not working efficiently even though it was seen to be running when I had the oven out of its housing and fully exposed.. The selector switch when I examined it looked in perfect condition, but difficult to have a thorough inspection unless I completely remove it.
Later this morning I am going to unscrew the cooling fan from its mounting on the outer wall and have a real good look and "sniff around "this component. There is a little bit more work in eliminating totally the selector switch but will only do this as a last resort, because as stated it does appear to be in sound condition visually from what I can see