Induction cooktop- INSTALLED!

[slowmachine]

Originally Posted by wil01

We don't understand all we know about is going on!

1 gallon of water weighs 8.33 lbs, so 2 quarts weigh 8.33 / 2 = 4.14 lbs

A btu is defined as the heat required to raise the temperature of one lb of water one degree F.

A watt can be defined as 3.41 btu.

In the two quart example, the heat required to increase the temperature of the water from 70 to 212 F is 4.14 * (212 - 70) = 591.43 btu

The required watts are 591.43 / 3.41 = 173.44 watts.

I don't what is going on, but something very strange is.

I'll do some more tests trying to unlock the mystery. I've now sent two True Induction units back because of their unusual results, including very limited low temperature adjustments.

Good Luck!
Wil

I think the largest factor is that the surface area of the vessel, to include the water surface, is simply dissipating more heat than the cooktop can overcome. I'm certain that we could get better performance with the lid on, but that's not really an option for pasta. If you read the post that I linked to earlier in this thread, you can see that the True Induction cooktop is more than capable of heating pan contents to temperatures higher than 400F, in the right sized pan.



Mike
2000 Holiday Rambler Endeavor 40PBD
Freghtliner XC, CAT 3126B

[MSHappyCampers]

Originally Posted by slowmachine

My GE is a Profile Series freestanding induction range with warming drawer, model PHB920SF2SS.

After a very close call last year with a malfunctioning propane range that leaked and filled our basement with explosive gas, we removed all of our propane appliances and the tank that fed them. Now that I have a few months of experience with it, I can say with certainty that we will never have gas again, at least not indoors. I don't think that I have lost any capability in the kitchen, and I don't miss the heat and fumes of the gas stove.



Mike
2000 Holiday Rambler Endeavor 40PBD
Freghtliner XC, CAT 3126B

Mike, is that in your RV or house?

I too would never have a house with gas!

[slowmachine]

Originally Posted by MSHappyCampers

Mike, is that in your RV or house?

I too would never have a house with gas!

Sorry if I wasn't clear. The GE range is in my home kitchen.



Mike
2000 Holiday Rambler Endeavor 40PBD
Freghtliner XC, CAT 3126B

[MSHappyCampers]

Originally Posted by slowmachine

Sorry if I wasn't clear. The GE range is in my home kitchen.



Mike
2000 Holiday Rambler Endeavor 40PBD
Freghtliner XC, CAT 3126B

So I assume that's a 240VAC model? If so, I guess we really can't compare it's performance with the RV models, right?

[slowmachine]

Originally Posted by MSHappyCampers

So I assume that's a 240VAC model? If so, I guess we really can't compare it's performance with the RV models, right?

Yes, it is 240V, 40A. It makes such quick work of stovetop cooking that I would seriously consider a 240V generator and cooktop in an all-electric MH.



Mike
2000 Holiday Rambler Endeavor 40PBD
Freghtliner XC, CAT 3126B

[wil01]

I just did some two quart testing to add information to this thread.

Pots:
5 qt. Magma stock pot, about 10" diameter
2 qt. Magma sauce pot, about 6" diameter
6" Circulon skillet

All induction ready.

Head Source:
NuWave Pro, now called Gold. Rated at 1500 watts

The beginning water temperature: 76 degrees F.

The NuWave was set on its highest setting, Ser.

5 qt. Stock Pot
Watts: 1640 to 1680
7 minutes to rolling boil.

2 qt sauce pot:
Watts: 1640 to 1680
Since watts input was the same, time to boiling not measured.

6" Circulon skillet:
1400 to 1420 watts.
Since it does not hold 2 quarts of water, time to boil not measured.

I think it is safe to conclude that the container does have a great effect on the performance of the induction unit.

It is also interesting that the size of the container of similar construction had no effect on the watts input with the NuWave, but the container of different construction did make a difference on the watts input.

The original "two quart" test by slowmachine documents that containers of different size with similar construction does make a difference in watts input with the True Induction.

In another post, I discuss some of the differences in the True Induction and the NuWave, and why I returned both of my True Induction units.

Good Luck!
Wil

[MSHappyCampers]

Wil, when I Googled the Nuwave Gold I see only portable one-burner cooktops. Is that what you're using, and if so, do they have a 2-burner model available?

BTW, thanks for your extensive info!

[wil01]

I think they only have one burner models and not for installing like you did. We just let ours stay on the original LP cooktop cover. Two will fit there if you desire.

For me, there are some issues with the True Induction unit that make it unacceptable to me. But before I list those, let me say that I haven't seen any units where the thermostat tells you the actual temperature of the food.

The thermostats are mounted on the underside of the cooktop, and as you know, induction heats the bottom of the pan directly. Then that heat is transferred to the pan contents and the cooktop itself. The heat must get through the resistance of the cooktop before it can register on the thermostat. The contents of the pan has little resistance when compared to the cooktop so the thermostat will be wrong much of the time.

You can overcome that thermostat problem by observing the container contents and modifying your heat setting by what you see happening in the container. With the NuWave, to get a proper simmer, we had to finally set the thermostat at 190 F. That provided a constant condition for an hour where the sauce just bubbled very slowly -- just what DW wanted.

We still had the True Induction and actually started the cooking of the sauce with it. It did the high heat part just fine, but there was no way to make it simmer properly. We just moved the pot to the NuWave and was able to get the proper simmer in about one minute.

Here are some more differences that remove The True Induction for us.


Heat settings
NuWave: 100 to 450 F in 5 degree steps.
True Induction: 150 to 450 in 30 degree steps (unacceptable)

Timer Settings
Nuwave: 99 hours. This means you can use it as a slow cooker.
Tru Induction 180 minutes.

Program Cooking
NuWave: Can be set for different temperatures at different cooking times.

All in all, we find the True Induction unacceptable

Good Luck!
Wil

[MSHappyCampers]

Just got off the phone with Tony at True Induction tech support.

First he had me try boiling 1 cup of water in a small saucepan (6" diameter). It came to a full boil in about 2 minutes. The voltage was reading 109.5 VAC and the wattage was 1310 watts.

He then tried boiling 2 qts. of water in a large boiler about the same size as mine. It came to a full boil in 9 minutes! That was the same test that I did and the water never boiled more than a few bubbles! He was not able to check the wattage as someone had borrowed his ampmeter and failed to return it!

He thinks it is the cookware that I have. He is sending me a boiler to try. We'll see what happens then!

[wil01]

The cookware is really a possibility. My recent test shows a difference in the induction efficiency of Magma and Circulon.

Searching the internet will also show that the cooking container construction will have an influence on performance.

Good Luck!
Wil

[slowmachine]

Originally Posted by wil01

Heat settings
NuWave: 100 to 450 F in 5 degree steps.

Wil, my NuWave temperature control is in 10 degree increments. The model number on the bottom is 30141 CR. Is your different? Mine is less than a year old.



Mike
2000 Holiday Rambler Endeavor 40PBD
Freghtliner XC, CAT 3126B

[wil01]

Yes, the 1300 watt version and the 1500 watt versions are different. The 1500 watt version (Pro/Gold) has 5 degree steps. The 1300 watt version has 10 degree steps.

Just to add to the conversation, we use 15.5 quart porcelain lined light weight steel pot to steam lobster, etc. You know the one, it's dark blue with white spots. It's about 14" diameter. The NuWave Pro (Gold) made the steam in a very short time. I didn't time it because I wasn't testing at the time. That just reminds me to get back to Maine and get some more lobsters.

Good Luck!
Wil

[spritz]

Sure seems like a lot of work to boil water. Sorry I'll stick with the old gas range. 50 years cooking with gas and no problems. I never liked electric.
Thanks for all the info though,
JS,JMO,
Tim

[wil01]

I now understand a little more about inducting cooking than when I first started.

1. Induction does no heating at all. It just creates an electrical circuit in the bottom of the cooking pan. That electrical circuit creates heat just like any other electrical circuit, exactly like your electric range. The difference is that the current produced by the induction circuit heats the pan and the electric range heats the heating coil which then heats the pan.

2. There are losses in every heat transfer process. The electric range loses heat to the air around it and to the surface between the heating coil and the pan. Induction removes both of these heat losses and therefor is more efficient. Both systems have the same heat losses from the heated container itself.

3. Calculating the amount of heat to heat water is simple, and so is calculating the number of watts to produce the desired results.

4. Using “rolling boil” as an end point to test how long the unit takes to do the heating is not very precise. It takes 1 BTU to raise the temperature of 1 pound of water 1 degree F, but it takes over 1,000 BTUs to change one pound of water at 212 F to one pound of steam at 212 F, and a rolling boil produces some steam. That means using just temperature difference without producing any steam will produce more accurate results – like from 70 F to 212 F.

5. It has been determined from the literature and actual current tests that the cooking container properties influence the watts produced by the unit. In my case, using a unit rated at 1,500 watts, Magma cookware of different sizes produced 1650+/- watts and Circulon produced 1450+/- watts.

6. It seems that the design of the induction coils in the unit also has an influence on the unit output. I have not seen tests to prove that, but I suspect it is so.

7. I ran some calculations through a spreadsheet and compared those calculations with my own results and the reported results of others. The figures are for two quarts of water heated from a temperature of 70 F to 212 F.

Watts -- Minutes
1300 – 8.0
1500 – 6.94
1600 – 6.50
1800 – 5.78
1000 – 10.41
800 -- 13.01

These are theoretical calculation and do not take in account any heat losses, and of course there will be those losses, but these calculations can tell you something about the efficiency of your unit and cooking pans. My own actual test results are very close to the calculated values.

You can also use the calculations to get some idea about just how “inductive ready” your cookware is.

The accepted understanding that all you need to do to determine if a pot is “induction ready” does work in a general way, but doesn’t tell anything about how efficient that pot will actually be in induction cooking. I suggest that the way to really tell if the pan is efficient is to put some water in the pan and set the unit to its highest setting. Then measure the watts the unit puts out. If those measured watts are close to the unit specifications, all is well. If they are much less than the unit specifications, there is a problem with either the pan or the unit.

8. There are also issues about unit controls, reliability, and seller issues, but those issues will be left for another post.

Good Luck!
Wil