When installing a control system for an ASHP, consideration should be given to the following:
- Place thermostats on interior wall (about 1.5 m high), away from direct sunlight, appliances, or drafts.
- Locate any outdoor thermostats in shady protected areas.
- In larger spaces (>300 ft2), a fixed, wall-mounted control should be installed in a location that will be representative of the space the unit is serving.
- For smaller rooms or isolated zones that have no significant thermal/comfort problems, return-air temperature sensing with a handheld remote is acceptable.
- Temperature sensing may need adjustment, especially for wall-mounted indoor units. Adjust sensing offset settings for 2-4⁰C ("more heating" and "less cooling") for high-wall installations and other situations where air distribution to the space may be compromised. Further adjustments might be required based on occupant feedback.
- Use an integrated multi-stage control for systems that include a central HVAC system as the supplementary heat source. If integrated multi-stage control is not available, use two thermostats.
- Check installer settings as needed. They should include the following, as applicable:
- Retain installer settings during power outage.
- Use "efficient home" settings when available to improve cycling behavior in low load situations.
- Some compact-ducted air handlers require adjustment for static pressure on duct systems.
- When available and not required due to ventilation requirements, installer settings shall be set to avoid continuous fan operation, even at low speeds.