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  1. MechEng92

    How should I work out Wattage for a heat exchanger pad heater?

    Amazing thank you :)
  2. MechEng92

    How should I work out Wattage for a heat exchanger pad heater?

    Hi Pierre thanks for commenting, this particular scenario will be when the system is not operating when in standby and so the fluid will not be flowing and therefore we need the heating to prevent freezing in colder ambient temperatures. I will speak with the HX supplier to see if they have...
  3. MechEng92

    How should I work out Wattage for a heat exchanger pad heater?

    Surface area of the heat exchanger as I'm potentially looking to use a pad heater. Insulation is going to be used but we still require heating to prevent freezing at very low ambient temperatures. Trace heating could work too.
  4. MechEng92

    How should I work out Wattage for a heat exchanger pad heater?

    Thank you, I know it's vague but I was hoping there was a generic method for calculating the Wattage which could be applied to any situation. I know the freezing temperature of the fluid and the ambient temperature, I'm sure I can get the material properties of the heat exchanger with...
  5. MechEng92

    How should I work out Wattage for a heat exchanger pad heater?

    I would like to size an adhesive pad heater to use on a brazed plate heat exchanger to prevent freezing in low ambient temperatures. How should I go about calculating the wattage?
  6. MechEng92

    Dead head regarding fans?

    Unfortunately no answer as to why it's behaving this way. It seems that the design team are going to limit the fan to a maximum control voltage based on the installation to get around it. So instead of 100% fan speed being the maximum it'll be more like 90%
  7. MechEng92

    Dead head regarding fans?

    Unsure if all fans are behaving the same but certainly more than one of them. I'll ask them to check the measurements against the name plate. Thank you :)
  8. MechEng92

    Dead head regarding fans?

    It's just a fixed fan speed, this scenario has happened on end of line test where the fans are manually set to 10V, as it has ramped up towards 10V (max. fan speed) it's shut down due to overheating at around 9.4V
  9. MechEng92

    Dead head regarding fans?

    I'll check tomorrow if the control signal can be checked but thank you very much this has probably been the most helpful response so far. We do have the fan supplier coming in soon to check what the issue could be also.
  10. MechEng92

    Dead head regarding fans?

    Sorry I wasn't available over the weekend hence why I'm responding this morning. And I've already stated a lot of this work is confidential and IP so I can't share specifics like data sheets.
  11. MechEng92

    Dead head regarding fans?

    Morning all, It's a fixed control signal, we send the voltage signal to the fans. When we set it to 10V and the fan speeds up, it's cutting out at around 9.4V due to overheating on the motor from high current. We're going to get the supplier in to take a look soon and give us their insight. I...
  12. MechEng92

    Dead head regarding fans?

    the 0-10V is an output from the product controller to the fan input. The fans are arranged in an array 3 x 2 wide and tall
  13. MechEng92

    Dead head regarding fans?

    Unfortunately I'm unable to share most of that due to either not being with the application to take measurement and IP. All I can say it's that it's a HVAC application, multiple EC centrifugal fans blowing air against an air filter and heat exchanger with no resistance on the fan inlets.
  14. MechEng92

    Dead head regarding fans?

    EC = Electronically Commutated, combination of DC and AC. Sorry if I'm coming across an idiot I still just can't get my head around how there's too flow going through it and it's not sized for the application. I would have assumed it would be able to go to 10V/max fan speed and provide whatever...
  15. MechEng92

    Dead head regarding fans?

    Morning all, The specifics are it's an EC centrifugal backward curved fan blowing against a resistance on the discharge side with very little resistance on the suction side. The fan is controlled by 0-10V and when getting up to 10V (after about 9.4V) the logic inside the motor is detection high...
  16. MechEng92

    Dead head regarding fans?

    So this particular fan isn't operating in a vacuum, and if anything is oversized for the system resistance. I think that's why I'm struggling to understand the issue because it should be the opposite of enough system resistance to cause dead heading
  17. MechEng92

    Dead head regarding fans?

    Okay thank you, so the scenario I'm seeing is a fan which definitely doesn't have too high system resistance but is cutting out before maximum fan speed due to current monitoring on the fan motor getting too high. However, applying additional resistance to the fan inlet helps to reduce the...
  18. MechEng92

    Dead head regarding fans?

    Thanks for linking the post but I still don't quite understand. Is dead heading when the system resistance is so high that the fan is at essentially zero airflow? Is there a scenario where the system resistance could be low and the fan dead heads?
  19. MechEng92

    Dead head regarding fans?

    Please could someone explain to me how dead heading relates to centrifugal fans in simple terms? I'm struggling to get my head around it. Thanks
  20. MechEng92

    Basic question - why are chilled water systems pressurised?

    Brilliant thank you :)

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