Why does my Viking gas oven take forever to preheat?

A gas oven that has become slow is not usually an oven that has become cool. It will very often reach the temperature you asked for in the end, and read perfectly well on a thermometer once it is there, and still take noticeably longer to get there than it did a year or two ago. What has changed is time rather than temperature, which is why nothing you measure ever seems to show it.

The part that explains most of these is the one that decides when gas is allowed into the cavity in the first place.

What has to happen before a gas oven starts heating at all

When you set a gas oven going, nothing burns straight away. An electric oven igniter has to warm up first, and only once it is doing its full job electrically does the oven’s gas valve open and the burner light. That order is deliberate: it makes it very hard indeed for gas to be released into a cavity where there is nothing hot enough to burn it.

The small pause you have always had at the beginning of a preheat is that sequence happening. What people do not always realise is that the burner then does not stay lit for the whole preheat. It comes on to add heat and goes off again when the control has had enough, over and over, and every single one of those restarts begins with the same little wait.

The weakening pattern, and why it creeps up on you

An igniter is a wearing part, and what wears is its willingness to reach the state that opens the valve. Early on, that shows up as a moment or two more at the start of each cycle, which nobody notices. Later, enough of every cycle is spent waiting that the preheat you have built a Sunday lunch around has quietly stretched out of recognition.

The reason it is so hard to catch is that it never happens on a particular day. It adds a little each month, the kitchen adjusts around it, and the new normal is accepted without anybody deciding to accept it. Ask yourself whether you have started putting the oven on before you unpack the shopping. If the honest answer is yes, that is the measurement.

The pattern has an end, and it is worth knowing what the end looks like. Eventually the igniter glows away as brightly as it ever did and the burner never lights at all. People find that genuinely confusing, because the visible half of the job is still being done perfectly. Glowing and doing the electrical work that lets the gas through are two different things, and one of them outlasts the other.

The things that are not the oven

Before booking anybody, rule out the four that turn up most often.

The kitchen itself is the first. Mornings near the water in Venice, Marina del Rey and Playa Vista start cool, and a cavity that begins colder has further to travel. The same oven in the same kitchen is genuinely slower in February than in August.

The second is what you have left inside. A baking stone, a steel plate or a stack of heavy trays all have to be brought up to temperature along with the oven, and the oven has no way of telling you that it is doing extra work.

The third is opening the door during the preheat. There is very little heat stored in the air, so a look inside costs more than it seems to.

The fourth is the ready tone. It tells you the air has arrived; the shelves and the walls have not. Load the moment it sounds and the oven has to make up that difference with the door open and cold food in it, which feels like slowness and is not.

When it stops being slow and becomes something to stop using

Slow is an inconvenience rather than a hazard, so long as the burner is still catching. Two things change that.

The first is the burner not lighting at all while the igniter carries on glowing. At that point, switch the oven off, leave it off, and book the visit. There is nothing to be gained by trying it again in an hour, and a gas appliance that has stopped doing what it is designed to do is not one to experiment with.

The second is any smell of gas, at any time, for any reason. Do not touch switches. Leave the building, and call your gas utility from outside, or 911.

None of this is owner territory. The igniter, the valve and the wiring between them all sit behind panels, and everything on that list is a technician’s job rather than a weekend one. Viking Repair Pros of Los Angeles takes calls on (213) 652-7030, and the flat $89 pays for the visit and for finding out which part of that sequence has given up.

Follow-ups

Is a slow preheat costing me anything on the gas bill?

Not enough to notice. The burner is not running for longer, it is waiting for longer, and waiting uses almost nothing. The real cost is the appointment you are heading towards, because the same wear that stretches out the wait ends, sooner or later, with an oven that will not light.

Does it help to set a higher temperature and then turn it down?

It does not. The wait happens at the start of every heating cycle whatever number you have chosen, so a higher setting buys you nothing and leaves a very hot cavity to bring back down. Set what the recipe wants and give the oven its time, or get the delay looked at.

The cooktop lights instantly. Doesn't that rule out a gas problem?

No, and that catches people out. The burners on the cooktop are lit a different way entirely, and they share nothing with the part that is holding up the oven. A cooktop that lights at once tells you nothing reassuring about the oven underneath it, so do not read it as a clean bill of health.

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