I have a goodman airhandler (mbr1600aa-1aa) with a 15kw heat pack(hkp1500). It will allow me to turn off the 30a breaker and run as a 10k, but I want to be able to turn off the 60a and run it as a 5k for heating my house when powered by a 6250 kn generator. I know I would need to transfer my power supply for my controls off the 60a breaker to the 30a breaker, but what do I do the sync switches?

Best to post this over in electric. I have done this before BUT I do not conside this a good choice. Check with them.

What does this mean?


but what do I do the the sync switches?

He probably means sequencers, but let him clarify. How Do Sequencers Work in Electric Furnaces? | eHow.com (http://www.ehow.com/how-does_5655422_do-sequencers-work-electric-furnaces_.html)

I'll comment more later, but I will add:

It does depend on element size and the elements are usually sized differently. e.g. You could have a 15 KW element and a 5 KW element. The 15's could be made up of two 5's.

It could take some effort and expense to "make" at 20 KW element behave as any element between 0 and 15 KW. The part to do this isn't cheap.

An example:

http://instrumentation-central.com/SCRPowerControls/pci_series.pdf

The manufacturer would have to be questioned to what happens on start-up, power loss/power up, loss of setput signal/restoration

Something to think about.

Putting elements in series MIGHT be a possibility,but it might not be the power level you desire. I doubt it would work.

Eurotherm makes some of the best stuff out there.

So, it's entirely possible to run a system with such a controller and with a little magic so it so it runs at 100% and X% based using a very small switch.

You could run it at say 5 KW and 1 KW based on a simple switch. Giving you a total of 15 KW in one one and 6 KW in the other.

I'd have to brush up before committing to a design.

One way is to ignore the sequencer's all together, use a small PLC and duct temperature and roll your own.

6 KW and maybe 5, 10 and 15 KW based on temperature rise.

Not cheap.

To be clear, I have 15k total. There are three 5k elements. Tow f them work off a 2p60a and the other off a 2p30a breaker. Ok, I got it up and running. I switched the control power wires from the 10kw(60a) breaker over to the 5kw(30a)breaker. This gave me the 5k heat but no blower. So I switched the blower feed that was on one of the 10k legs, over to one of the 5k legs and all works well. So now, I can have some heat running off my generator when the power goes down. Thanks for your hel folks!

I'll assume you have an all electric home. Are you planning to run anything else on the generator?

No, it's got propane for dryer and stove. Every year, the power goes out after ice storms for a couple days. We can get by with just the furnace and a light or two. This was for emergancy heat only.

We have a similar situation here in Missouri with ice storms. I purchased a small propane stove / fireplace for part of the house to take care of the heat and left the furnace alone. And I do have a generator to take care of the freezer and refrigerator, and necessary lights.