WattMaster Water Source Heat Pump, Installation & Operation Manual

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Section 1
WattMaster WHP
1-12
Design Guide
Heat Rejection Control
If the compressor is not running, no heat rejection can be active. If any heat rejection is
still active when the compressor is turned off, the heat rejection will be immediately
removed, without regard to any minimum run or off times.
Heat rejection cannot be active at the same time as heat addition, so any heat addition is
removed or staged off before the heat rejection can be started.
A maximum of 8 stages of heat rejection can be controlled.
Staged Heat Rejection
Heat Rejection is staged up based on a different deadband level for each stage. Basically,
if the user programmed a 2° deadband, then the first stage could activate at the setpoint,
stage 2 would activate 2° above the setpoint, stage 3 would activate 4° above the setpoint,
etc...
Staging down is calculated in the same manner, except the water temperature would need
to drop below the setpoint by the deadband amount. If stage 3 was activated at 4° above
setpoint, it would de-activate when the temperature fell to within 2° of setpoint, stage 2
would de-activate at setpoint and stage 1 would de-activate 2° below setpoint.
A user defined staging up and down interval must be met before any heat rejection stages
can be added or removed. If the selected Water Temperature is above the current staging
level and the timer has been satisfied, an additional stage can be added, up to the
maximum available 8 stages. If the selected Water Temperature is below the staging
down level and the timer has been satisfied, a stage can be removed.
Heat Addition Control
If the compressor is not running, no heat addition can be active. If any heat addition is
still active when the compressor is turned off, the heat addition will be immediately
removed, without regard to any minimum run or off times.
Heat addition cannot be active at the same time as heat rejection, so any heat rejection is
removed or staged off before the heat addition can be started.
A maximum of 4 stages of heat addition can be controlled or proportional heating can be
configured, and an analog output signal will be modulated to control the heat.