It is possible to do what you want to do but you will regret it...poor heat performance will be th e end result. Heat pumps require defrost intervals which means compressor AND heat strips be energized. That and a few other reasons will make you VERY unhappy with your system.

 

Yes, the system is operating properly. The electric backup is supposed to run at the same time as the heat pump. It's possible to change this, so the heat pump shuts off when electric backup is called for, by setting it to a dual fuel system. But not a good idea, as locking out the heat pump when backup is needed means higher energy costs, as likely both electric elements would need to run without the heat pump there to help.

 

Not to mention that defrost thing...lol

 

Find out just how much hea


t strip you have (5kw..10kw..15kw) if you can get away with disabling a 5kw strip...this may get you where ya wanna go. i.e. if you have 10kw disable 5kw..You may get lucky and not lose too much performance from your system

 

It seems a bit foolish to me to drop 3kW of heat so you are forced to use 10. Why not just upgrade the service to the amperage you need and be done with it, or will they not let you do that.

Seems odd in an era where they want to be more energy efficient to shut of the more efficient of 2 heat sources.

 

Remember this in CANADA, so things MAY be a bit different than in the US.

 

yup...I think he is trying to save the cost of a proper electric upgrade...

 

at the expense of poor system performance...

 

Just have your electrician put in a load shed controller for your car charger or have it wired so your electric clothes dryer and the car charger cannot operate at the same time.

Your electrician should be familiar with all of this otherwise I would finding one more familiar with car charger installs.

Sent from my SM-S906W using Tapatalk

 

Thanks for your thoughts all.

Here is my follow up question:

In the manual, it says that if the backup heat source is gas/forced air, then the heat pump is not allowed to run.

So, it seems likely that the "defrost thing" is not really a factor to consider, since folks who installed this heat pump with a oil/gas backup system would also not have them able to run at the same time, right?

If the heat pump goes into defrost mode and aux heat doesn't turn on then it will be effectively air conditioning my house though right?

So I think it really is just mostly just a question of economics that is driving the control algorithm on the Honeywell software.


We already got a service upgrade to 200 A about 2 years ago, not eager to do it again. The linesmen said that transformer feeding my house was already maxed out when they connected me to 200A... but could be worth getting a quote!

The number of times that we need the backup heat throughout the year is pretty low, so I think it may be worth pursuing the dual-heat lockout in the controller a bit further. The COP for my heat pump is probably

Does anyone know if the heat pump and backup will run at the same time when the heat pump is in a defrost mode with the Prestige IAQ? (even if the controller is configured not to run backup/heat pump at the same time?)

Another option might be to use an EV charger that has load management capabilities. For example the EVduty system has a wirelessly networked "smart current sensor" feature that allows the charger to ramp down its charge current based on a configurable whole-home current consumption threshold profile. Kinda pricy though! like $500 just for the sensor!

Or a load shed device.

Or I just do an EV charger with a configurable output current, and limit it to 28A or lower (12.5% slower charge rate).

I think this is probably the most sensible answer.