How to test and use an oven without a Hechsher

1. How has this guide been constructed?

This guide is intended to educate the consumer as to how an oven without an approved ‘Sabbath mode’ can be used to keep food hot for Shabbos. There are two major problems with using an oven on Shabbos:

1) Direct electronic activity caused by the opening of the door such as the operation of the light or fan

2) Indirect electronic activity caused by the introduction of cold air to the oven cavity.

This guide will show how both problems can be tested for and potentially bypassed.

2. How do I know if opening my oven door causes direct electronic activity?

Here are our instructions for checking to see if the opening of an oven door triggers any direct electronic activity:

No oven may be used if opening and closing the door triggers a light, makes changes to a display screen, starts/stops a fan/lights. These points must be researched before using any oven on Shabbos.

In some cases, it will be possible to neutralise these problems by taping down a small door switch – look carefully to find it

To test the oven, turn the oven to ‘on’ – and then open the door.

Check that no light is lit, and listen out to see if the fan operates

Check that nothing changes on the LED screen

Then test the oven when the oven is set to ‘off’, does the light come on when the door opens, is there a change on the digital display screen?

In some appliances, the element is programmed to switch off when the door opens. The manufacturer should be contacted and asked whether the element is affected by the door opening and closing

You can test this yourself is by turning on the oven and turning off all other power using devices in the house (by turning off the fuses). When the oven is heating, the power on your home’s electric meter will be moving. Open the door and get someone else to look at the meter. If the meter stops or slows significantly as the door was opened then it is likely that this safety feature is in fact in operation in your device. Close the door, does the power usage resume?

Taping down a door switch will only help bypass the issues of the direct activities caused by opening the door, however, there are still indirect electronic activities that must be neutralised before one may use an oven on Shabbos or Yom Tov. Please read on in Q’s 3 – 5 for how to do this.
If one is not able to neutralise the direct electronic activities caused by the opening of the oven door, the oven may not be used on Shabbos or Yom Tov.

3. How do I bypass the issues caused by indirect electronic activity?

Whilst the oven is running, if the door is opened, even if the door switch has been neutralised, cold air will enter the oven, which will cause the element to switch on earlier than expected. This is a Halachic issue on Shabbos. For use on Yom Tov please see Q5.

If a timer is set which will shut off all electronic activity in the oven, the oven may be opened and closed once the oven has switched off.

The following instructions apply:

All food must be fully cooked, warm and in place in the oven before Shabbos, in accordance with the instructions in the guide ‘How to keep food warm in an oven on Shabbos’.
The timer should be set before Shabbos to switch the oven off in time for your Shabbos meal.

The door may only be opened once the timer has closed off all appliance activity.

The alarm indicating the end of the desired cooking program may not be switched off on Shabbos. If opening the door switches off the alarm, this is problematic and the oven cannot be used in this way.

NOTE – some models carry a timer whose alarm will continue to sound until it is switched off; in others an icon is cancelled when the door is opened; these models are not suitable for Shabbos use.

This solution is only permitted if one has neutralised all direct activity the opening of the door has on the appliance as explained in Q2.

4. Can ovens which do not have a timer be used on Shabbos?

In Question 3, we gave instruction for the use of an oven which has no Sabbath mode, through the traditional use of a timer which shuts off all appliance activity.

A further possibility exists for cases where no timer function is available; this approach allows for opening the oven when the element is working, and the Federation Beis Din have deemed this acceptable.

As described in question 2, no oven may be used if opening and closing the door triggers a light, makes changes to a display screen, starts/stops a fan/lights or it switches off a heating element. These points must be researched and resolved before using any oven on Shabbos. Here are our instructions for use of an appliance when the element is lit:

All food must be fully cooked, warm and in place in the oven before Shabbos, in accordance with the instructions in the guide ‘How to keep my food warm in an oven on Shabbos’.

In ovens which have an element indicator light, when the light glows brightly, this shows that the element is active and heating.

One may open the door when the light is showing brightly.

The oven should then be closed swiftly.

The door can be opened and closed repeatedly, whilst the light shines brightly.

For ovens which do not feature such an indicator light, FedTech offer a device which can be installed in such ovens and acts as an external element indicator light. To read more about this and to purchase such an indicator light please click here.

5. What are the Yom Tov rules for the operation of an oven?

On Yom Tov, cooking is permitted; however, switching on and turning off an oven are forbidden. Similarly, adjusting the temperature on an oven is not permitted. Our guidelines for oven use are as follows:

No oven may be used if opening and closing the door triggers a light, makes changes to a display screen, starts/stops a fan/lights or it switches off a heating element. These points must be researched before using any oven on Shabbos or Yom Tov. For a guide to this please see Q2

If the oven is working in thermostatic mode and the door opening does not directly affect its operation, the oven may be used for Yom Tov cooking.

No adjustments may be made to the temperature setting over the course of Yom Tov.

Food may be placed in the oven to cook or heat on Yom Tov and need not be in place from before Yom Tov.

The door may be opened and closed as is required over the course of cooking.

6. What do I do if I have questions about this guide?

As always, if you require assistance, the ShailaText team of Rabbonim is available on 07403939613 .
Questions can also be forwarded to technology@federation.org.uk.