Geome,

This information may be helpful to your contractor when sizing a generator.

WaterFurnace International, Inc.

That's impressive - being able to start a 5 ton heat pump with a 7 kw generator is astounding.

Does Intellistart come with any efficiency penalty during steady state operation?

Is it expected that soft starts will aid in compressor durability?

If widely adopted the technology could make whole-house standby generators much more feasible, and those houses much more comfortable during long outages.

I hope it would spawn production of quiet, high efficiency 1800 rpm 4-pole generators in smaller kw sizes.

A smart transfer switch could sequence other big loads in the house (range, dryer, water heater, heat pump) so as to allow limited operation of those loads during an outage. It might be configured to drop the range and water heater during a heat pump start and then return them to service.

Other possibilities include dropping electric storage water heater voltage from 240 to 120. That cuts wattage by 75%, quadruples recovery time, but still makes some hot water available during an extended outage.

engineer,

The IntelliStart does not penalize efficiency during steady state operation.  This feature assists the compressor circuit during start up.  As for aiding in compressor durability, we are not aware of any testing that has been done to confirm this; however, many compressor failure modes can be related to startup.

WaterFurnace International, Inc.

Does sound great, but I would want to see independent verification of such low starting loads.

Very nice to have WF posting here.

Here is the US all 50 states have adopted some form of the National Electric Code. And while I'm not a electrician a generator wired into the home's wiring is required to have a disconnect switch (basically it cuts the main breaker) so you can't send your self-generated 110/220 down the line. I'm having a Intellistart installed on April 2nd in my WF Envision 3ton.

CHuntMD ~ Are you installing the intellistart for the sole purpose of being able to better run a generator in a power outage? I'd love to hear about how it goes... i.e. what size generator you can use with the intellistart and how difficult it was to install (for your contractor).

I was thinking of an intellistart with a generlink set up for my situation, but I'm still in the beginning of the planning process.

Future planning for a NG fed generator but I do like the idea of a smooth start for motors. I'm entering the shoulder seasons here in Wash DC and just last weekend I heard the hot-water tank kick in after a shower. Dec/Jan/Feb I used 8 therms of NG total.

Now that we have the attachment, the generator size needed is dependent on the generator overload characteristics. A safe value should be 2x the normal motor draw (a great improvement over 5x or 6x). Ie, I'd get a 10Kw generator for 5 tons - cutting it too close could be an expensive mistake.

Thanks WF! Sorry for the delay in responding. I've been out of town.