Temperatures exceeding thermostat deadbands

[mnblonsky]

When running at 1 minute timesteps, the thermostat control with deadband can exceed the deadband limits. It's mainly an issue for the water heater, which can increase in temperature pretty quickly. It's an issue for HVAC too, but not as significant.

It'd be nice to add a feature to reduce the power of the equipment when it hits the top/bottom of the deadband. This would be similar to the ideal capacity algorithm, but not exactly the same. Maybe an algorithm like this:

• Determine thermostat mode (on/off)
• Determine ideal capacity using the top/bottom of the deadband depending on mode
• Set capacity to the ideal, capped at the min/max capacity of the equipment

Might need to think a little harder about this for HPWH and ASHP. But I think something should be able to work. It might even simplify the methods we have for ideal capacity now (at least for HPWH).