Danfoss DHP-A Service Instructions Manual

Also see for DHP-A: User guide User manual Installation and service instructions User manual Installation and service instructions

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Danfoss DHP-A Service Instructions Manual Manual pdf 34 page image

Symbol explanation15 INTEGRAL A316 External auxiliary heaterThe calculation of the integral value stops during heat stop. The calculation of the integral value stops when heatstop has stopped.In this example INTEGRAL A3 < INTEGRAL A2. This means that the external addition will be activated earlier thanthe internal addition. On the condition that these are activated.9.8 HYSTERESISIn order to start the heat in advance during sudden changes of the heat demand, there is a value, HYSTERESIS,which controls the difference between the actual supply temperature, t1 and the calculated supply temperature,t2. If the difference is equal to or greater than the set HYSTERESIS value (x), i.e. there is a heat demand, or the heatdemand disappears, quicker than the usual integral calculation, the integral value is forced to either the start value(-60) INTEGRAL A1 or to the stop value (0).1 52893467Figure 26. Conditions for HYSTERESIS to force the integral value to change.Position Description1 Integral2 Supply temperature3 t14 t25 Time6 Compressor stop (0)7 Compressor start (-60)8 Hysteresis (Δt) ≥ x9 Hysteresis (Δt) ≥ x9.9 DEFR CURVETo start defrosting the outdoor unit for DHP A/DHP AL, the control computer makes a calculation using the tem-perature of the brine return and the outdoor temperature.The calculation is based on a linear defrosting curve that can be set so that the heat pump and outdoor unit workoptimally. The setting of three different values can be changed: DEFR CURVE 0, DEFR CURVE -20 and OUTDOORSTOP. The defrosting sequence starts when the temperature of the brine return reaches the set parameter valuefor the defrosting curve at an outdoor temperature somewhere along the defrosting curve.32 – Service instructions VMGFC302