The following configuration of cooling loops in energyplus works with just a few of warnings which I will mention seems ok (coolingload operation control and two setpoints and HX hasoperationschememodulated control):

Now I want my pumps and chillers to have different sizes, but HeaderedPumps:ConstantSpeed gives identical pumps, so I decided to go with the following configuration with Pump:ConstantSpeed (only change):

I got plenty several of these warnings, warningss in one-day simulation, at the time that setpoint rises goes from 3 to 6.7:

*************  ** Warning ** HeatExchanger:FluidToFluid named HX - Iteration Limit exceeded calculating demand side loop flow rate continues.
   *************  **   ~~~   **   This error occurred 29 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.
   *************  **   ~~~   **   Max=74.812813  Min=0.616959

It seems that when the setpoint goes from 3 to 6.7, plant has fluid in supply side with temperature lower than new setpoint (6.7). So it stops working while Heatexchanger is demanding load. I don't know if it's a bug or is something I'm doing wrong. I will be grateful for any suggestion to resolve this issue.

Update: I'm trying an EMS (python) solution like below but it doesn't work:

If demand>0 & PLR1==0 & PLR2==0:
    pump1 (actuator) = ON
    pump2 (actuator)= ON
    pump1 flow (actuator)= max (internal variable)
    pump2 flow (actuator)= max (internal variable)

The conditions are right but pumps flow does not change. I don't no why!

The following configuration of cooling loops in energyplus works with just a few warnings which seems ok without any warning (coolingload operation control and two setpoints and HX hasoperationschememodulated control):

Now I want my pumps and chillers to have different sizes, but HeaderedPumps:ConstantSpeed gives identical pumps, so I decided to go with the following configuration with Pump:ConstantSpeed (only change):

I got several of these warningss in the time that setpoint goes from 3 to 6.7:

*************  ** Warning ** HeatExchanger:FluidToFluid named HX - Iteration Limit exceeded calculating demand side loop flow rate continues.
   *************  **   ~~~   **   This error occurred 29 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.
   *************  **   ~~~   **   Max=74.812813  Min=0.616959

It seems that when the setpoint goes from 3 to 6.7, plant has fluid in supply side with temperature lower than new setpoint (6.7). So it stops working while Heatexchanger is demanding load. I don't know if it's a bug or is something I'm doing wrong. I will be grateful for any suggestion to resolve this issue.

Update: I'm trying an EMS (python) solution like below but it doesn't work:

If demand>0 & PLR1==0 & PLR2==0:
    pump1 (actuator) = ON
    pump2 (actuator)= ON
    pump1 pump 1 flow (actuator)= max (internal variable)
    pump2 pump 2 flow (actuator)= max (internal variable)

The conditions are right but pumps flow does not change. I don't no why!

The following configuration of cooling loops in energyplus works without any warning (coolingload operation control and two setpoints and HX hasoperationschememodulated control):

I want my pumps and chillers to have different sizes, but HeaderedPumps:ConstantSpeed gives identical pumps, so I decided to go with the following configuration with Pump:ConstantSpeed (only change):

I got several of these warningss in the time that setpoint goes from 3 to 6.7:

*************  ** Warning ** HeatExchanger:FluidToFluid named HX - Iteration Limit exceeded calculating demand side loop flow rate continues.
   *************  **   ~~~   **   This error occurred 29 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.
   *************  **   ~~~   **   Max=74.812813  Min=0.616959

It seems that when the setpoint goes from 3 to 6.7, plant has fluid in supply side with temperature lower than new setpoint (6.7). So it stops working while Heatexchanger is demanding load. I don't know if it's a bug or is something I'm doing wrong. I will be grateful for any suggestion to resolve this issue.

Update: I'm trying an EMS (python) solution like below but it doesn't work:

If demand>0 & PLR1==0 & PLR2==0:
    pump1 (actuator) = ON
    pump2 (actuator)= = ON
    pump 1 flow (actuator)= max (internal variable)
= max
    pump 2 flow (actuator)= max (internal variable)
= max

The conditions are right but pumps flow does not change. I don't no why!

The following configuration of cooling loops in energyplus works without any warning (coolingload operation control and two setpoints and HX hasoperationschememodulated control):

I want my pumps and chillers to have different sizes, but HeaderedPumps:ConstantSpeed gives identical pumps, so I decided to go with the following configuration with Pump:ConstantSpeed (only change):

I got several of these warningss in the time that setpoint goes from 3 to 6.7:

*************  ** Warning ** HeatExchanger:FluidToFluid named HX - Iteration Limit exceeded calculating demand side loop flow rate continues.
   *************  **   ~~~   **   This error occurred 29 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.
   *************  **   ~~~   **   Max=74.812813  Min=0.616959

It seems that when the setpoint goes from 3 to 6.7, plant has fluid in supply side with temperature lower than new setpoint (6.7). So it stops working while Heatexchanger is demanding load. I don't know if it's a bug or is something I'm doing wrong. I will be grateful for any suggestion to resolve this issue.

Update: I'm trying an EMS (python) solution like below but it doesn't work:

If demand>0 & PLR1==0 & PLR2==0:
    pump1 = ON
    pump2 = ON
    pump 1 flow = max
    pump 2 flow = max

The following configuration of cooling loops in energyplus works without any warning (coolingload operation control and two setpoints and HX hasoperationschememodulated control):

I want my pumps and chillers to have different sizes, but HeaderedPumps:ConstantSpeed gives identical pumps, so I decided to go with the following configuration with Pump:ConstantSpeed (only change):

I got several of these warningss in the time that setpoint goes from 3 to 6.7:

*************  ** Warning ** HeatExchanger:FluidToFluid named HX - Iteration Limit exceeded calculating demand side loop flow rate continues.
   *************  **   ~~~   **   This error occurred 29 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.
   *************  **   ~~~   **   Max=74.812813  Min=0.616959

It seems that when the setpoint goes from 3 to 6.7, plant has fluid in supply side with temperature lower than new setpoint (6.7). So it stops working while Heatexchanger is demanding load. I don't know if it's a bug or is something I'm doing wrong. I will be grateful for any suggestion to resolve this issue.

If demand>0 & PLR1==0 & PLR2==0:
    pump1 = ON
    pump2 = ON
    pump 1 flow = max
    pump 2 flow = max

The following configuration of cooling loops in energyplus works without any warning (coolingload operation control and two setpoints and HX hasoperationschememodulated control):

I want my pumps and chillers to have different sizes, but HeaderedPumps:ConstantSpeed gives identical pumps, so I decided to go with the following configuration with Pump:ConstantSpeed (only change):

I got several of these warningss in the time that setpoint goes from 3 to 6.7:

*************  ** Warning ** HeatExchanger:FluidToFluid named HX - Iteration Limit exceeded calculating demand side loop flow rate continues.
   *************  **   ~~~   **   This error occurred 29 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.
   *************  **   ~~~   **   Max=74.812813  Min=0.616959

It seems that when the setpoint goes from 3 to 6.7, plant has fluid in supply side with temperature lower than new setpoint (6.7). So it stops working while Heatexchanger is demanding load. I don't know if it's a bug or is something I'm doing wrong. I will be grateful for any suggestion to resolve this issue.

The following configuration of cooling loops in energyplus works without any warning (coolingload operation control and two setpoints and HX hasoperationschememodulated control):

control):

I want my pumps and chillers to have different sizes, but HeaderedPumps:ConstantSpeed gives identical pumps, so I decided to go with the following configuration with Pump:ConstantSpeed (only change):

I got several of these warningss in the time that setpoint goes from 3 to 6.7:

*************  ** Warning ** HeatExchanger:FluidToFluid named HX - Iteration Limit exceeded calculating demand side loop flow rate continues.
   *************  **   ~~~   **   This error occurred 29 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.
   *************  **   ~~~   **   Max=74.812813  Min=0.616959

It seems that when the setpoint goes from 3 to 6.7, plant has fluid in supply side with temperature lower than new setpoint (6.7). So it stops working while Heatexchanger is demanding load. I don't know if it's a bug or is something I'm doing wrong. I will be grateful for any suggestion to resolve this issue.

The following configuration of cooling loops in energyplus works worrks without any warning (coolingload operation control and two setpoints and HX hasoperationschememodulated control):

I want my pumps and chillers to have different sizes, but HeaderedPumps:ConstantSpeed gives identical pumps, so I decided to go with the following configuration with Pump:ConstantSpeed (only change):

I got several of these warningss warning in the time that setpoint goes from 3 to 6.7:

*************  ** Warning ** HeatExchanger:FluidToFluid named HX - Iteration Limit exceeded calculating demand side loop flow rate continues.
   *************  **   ~~~   **   This error occurred 29 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.
   *************  **   ~~~   **   Max=74.812813  Min=0.616959

It seems that when the setpoint goes from 3 to 6.7, plant has fluid in supply side with temperature lower than new setpoint (6.7). So it stops working while Heatexchanger is demanding load. I don't know if it's a bug or is something I'm doing wrong. I will be grateful for any suggestion to resolve this issue.