Oven Thermostat Testing

[jontymox]

Hello everyone,

Could someone let me know if it is possible to electrically test oven thermostats?

I have a problem with a Baumatic Range Cooker whereby the main oven (fan assisted) will not heat above 200 degrees c.

The element gives a high resistance reading, although does not get red hot.

I have renewed the thermostat, and ordered a new element due to arrive tomorrow.

I won’t know if renewing the element will cure the problem until then.

Has anyone come across similar faults?

Also wondering if there is a safety cut out thermostat somewhere, that I have overlooked.

jontymox

[Specialist01269]

Re: Oven Thermostat Testing

Hi Jonty, The way I normally test them is: Use a Thermometer with a flexible probe in the oven to check temp & either a Multimeter or Test Lamp across the output of the stat, turn stat to required temp & wait while watching the thermometer & meter to see what temp the oven cuts out at.
When you say the element is high resistance, how high?

[jontymox]

Re: Oven Thermostat Testing

Hello Specialist01269,

Thanks for your feedback.

The elements’ resistance goes “OL” on my insulation tester, although doesn’t look too healthy; i.e. it is a 3 turn element, and is discoloured/not uniform in colour/appearance.

Have you or anyone come across faulty elements, even though they give high resistance readings?

jontymox

[Specialist01269]

Re: Oven Thermostat Testing

Hi Jonty: If the element is showing o/l on your Insulation tester then I think you’ve already found your problem, a good element should have a relatively low resistance when tested across it’s connecting terminals (Wires disconnected). I normally test elements with a Multimeter first to find out if they are o/c or high resistance & then use the 500 volt insulation test for L/N to Earth if you have a Trip fault. If your using the continuity feature on your Insulation tester then this may not be capable of testing Elements, a lot of Testers only test up to 50 Ohms on continuity.

[jontymox]

Re: Oven Thermostat Testing

Thanks again,

Yes, I tested the element as normal with my insulation tester, (one connection to a terminal, the other connection to the element itself) and thought as the reading was “O/L” with 500 volts applied it was ok; thus I renewed the thermostat.

However, I did not test for continuity until just now.

With my separate multimeter set on the 0-200 Ohms scale, I obtained 22.3 Ohms across the terminals.

A new Hotpoint/Indesit element provides a similar reading of 21.6 Ohms, so I remain a little bemused.

jontymox

[chezza]

Re: Oven Thermostat Testing

As advised on the other thread you started on this, most likely cause of your problem is a duff base or upper element ….. unless you have tested them since the last time you asked ?

[jontymox]

Re: Oven Thermostat Testing

Hello chezza,

It’s purely the fan oven at fault.

Whereas the lower element can be selected with fan operation, the customers concern is the fan oven not heating above 200 degrees C.

This is definetely when the fan oven is selected.

In the user manual this clearly states this to be the circular heating element, together with fan operation.

Static oven heating can also be selected, with heat from top and bottom elements.

Regards,

jontymox

[Specialist01269]

Re: Oven Thermostat Testing

Hi Jonty: From those results then it would seem that the Element is ok. 2.6Kwatt yes? my next step would be to connect a Multimeter across the Element terminals with temp probe in oven & see what voltage was across the element & what temp it cut out at, without benefit of a diagram then I would trace the wiring from the element back to the stat or control PCB if one is fitted.

[Martin]

Re: Oven Thermostat Testing

jontymox wrote:Yes, I tested the element as normal with my insulation tester, (one connection to a terminal, the other connection to the element itself) and thought as the reading was “O/L” with 500 volts applied

“O/L”???…Change the circular fan element, that’s your problem my friend.!

[Specialist01269]

Re: Oven Thermostat Testing

Hi Martin: The O/L reading was from L/N to Earth, he had a 22 Ohm reading across the element.

[Martin]

Re: Oven Thermostat Testing

And there was me thinking O/L meant SHORT CIRCUIT. :rolls:

[Specialist01269]

Re: Oven Thermostat Testing

Depends on the meter, some show O/L for an o/c connection & others for a s/c. As it’s not tripping I took it to mean o/c.

[EFS]

Re: Oven Thermostat Testing

You didn’t say how the temp was being measured.

If its just the customers say so and they are using one of those rotary dial thermometers I would check the temp with a digital meter.

Is the door closing tight?

Seals ok?

Does the cooker have a cooling fan and is it working?

Has the element been replaced in the past with a lower wattage part that can’t get the oven hot enough?

Steve

[leavemetogetonwithit]

Re: Oven Thermostat Testing

Are there any trays or dishes obstructing vents in the fan cover?
Mike.

[Specialist01269]

Re: Oven Thermostat Testing

Hey Jonty: Did you get this 1 sorted?

[Author]

Posts