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  1. WilliamTz

    Temperature Control Unit... Glycol heating and coolgin

    LettleInch In cooling mode chilled glycol is delivered to the short header and the valve on the return line opens to meet the SP temp requirements. The secondary pumps take the water form the header and delivers it back into the header again on the return line. I always believed valves or non...
  2. WilliamTz

    Temperature Control Unit... Glycol heating and coolgin

    Hello Engineers, I have a small glycol system at -5degC in a primary/secondary pumping arrangement. The glycol serves process vessel jackets through a Temperature control unit, to cool and heat the process inside of them...see attached sketch....each approx 15kW. The glycol control valve at...
  3. WilliamTz

    Duct sizing

    Hello I am upgrading an old 1980's Office that uses circular duct throughout for HVAC. I want to retain the old circular duct downstream of the air handler as much as possible up as far as new VAV boxes I intend installing.. I usually use 1pa/m when sizing ductwork and that is how I intend...
  4. WilliamTz

    Pretreating outside air

    Hello Quesiton: In an air handling system with outside air and return air is it cheaper to treat the outsdie air first (dehum) before mixing with the return air. Or will the same dehum/reheat energy be used if you just mix and treat the mixed air? Thanks!
  5. WilliamTz

    MTHW for HVAC heating coil

    Thanks GT-EGR....some great posts and information!
  6. WilliamTz

    MTHW for HVAC heating coil

    GT-EGR Interesting arrangement. What do you think of the attached slightly modified; Use 2-port and retain the "decoupling line" as you previously mentioned. Use a 3 port diverting valve further down in front of the coil and a constant volume pump. What do you think? Regards...
  7. WilliamTz

    MTHW for HVAC heating coil

    Hello GT-EGR. Thanks for your tip! Does the attached sketch look ok. Some diagrams show what you explained with no control over the MTHW supply and just a bypass before the mixing valve and pump arrangement. Can I delete the by pass and put in a 2 port valve since the overall system is 2...
  8. WilliamTz

    MTHW for HVAC heating coil

    Hello Has anyone any suggestions regarding trying to control an air handler off heating coil temperature when using MTHW at 135degC Control is very difficult and the temperature tend to over shoot.... its the huge difference between the water temp and the desired air temp is the problem I...
  9. WilliamTz

    Cooling tower

    Hello If I have a number of cooling tower in parallel all connected with an equalization line can I delete the automated outlet valve and just rely on the inlet automated valve shutting off when the tower is not being used? Regards W
  10. WilliamTz

    Steam vs Hot Water Heating

    Hi ME272 I'd go with the steam to the individual buildings and at each building install a Steam to LPHW heat exchanger. Distribute LPHW to the heating coils thereafter Steam to the buildings is very efficient was of distributing energy where you have long runs from a central boiler house. LPHW...
  11. WilliamTz

    I have a problem with vibration and

    Pic 3https://files.engineering.com/getfile.aspx?folder=d626331e-e117-49fe-bd82-868fa39291a7&file=20200624_190429.jpg
  12. WilliamTz

    I have a problem with vibration and

    pic2 https://files.engineering.com/getfile.aspx?folder=44f5402e-f3e0-416c-b034-808b1e27bcc7&file=20200624_190105.jpg
  13. WilliamTz

    I have a problem with vibration and

    PIC 1https://files.engineering.com/getfile.aspx?folder=805eb9be-82e2-4298-94d9-c1dd5b5eec25&file=20200628_111724.jpg
  14. WilliamTz

    I have a problem with vibration and

    Hello Thanks for the feedback I have attached a sketch in schematic format and some pictures of the primary pumps header We usually need the 4+5 mW boiler ON or the 5+2mW or 4+2mW boiler ON together. Occasionally mid winter we need all 3 x boiler ON Number of primary pumps running = number of...
  15. WilliamTz

    I have a problem with vibration and

    I have a problem with vibration and pipes shaking in a boiler room. 3 x boilers 4mW, 5mW and 2 mW. Pipes range from 200mm to 450mm headers. Water temps at 138degC 6 bar pressure min. Primary pumps next to the boiler all on a header . The 2mW boiler was added recently. When running after a while...
  16. WilliamTz

    Faulty non return valve on pump

    Artist Yes. The non return valves passing is not the issue. The chiller cuts out on low condenser water flow every 24-48 hours approx. Head wrecing trying to find the reason I arrive at the chiller. Valves on chiller n towers closed and pump off. Alarm on the chiller. Could air be getting in ? B
  17. WilliamTz

    Faulty non return valve on pump

    Hi I got 4 x Condenser water pumps in parallel....2 new and 2 old.... non return valves on each Occasionally I loose condenser water flow through the chiller when running of the new pumps I did notice water flow noise coming from the two old the condenser water pumps, when they were off off...
  18. WilliamTz

    Pump Cavitation

    Hi LittleInch Yes thanks for all your help + others....The towers still overflow when pumps turned off and the inlet and outlet valves are still open. I have yet to figure out if its filling from the inlet or filling from the outlet.... Ill be back when I figure it out. Regards Billy
  19. WilliamTz

    Pump Cavitation

    I have figured this out.... the problem was the pump(s) was running at full speed with all towers and chillers available so it was doing too much and running towards the end of the pump range causing the guage to hop all over the place. I have figured out where to run the VSD (40hz) and...
  20. WilliamTz

    Pump performance unstable.

    This is a follow on from a previous question...see attached sketch I have a large condenser water system. Cooling tower , pumps etc. Back to 3 chillers When ever all the pumps atop the water continues to fill into the towers from the FLOW IN side and it overflows the towers. Is this due to...

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