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Basic Purge Zone Question -

moots
moots Member Posts: 35
edited August 2022 in Radiant Heating
Greetings:

Just moved into this house with an unfamiliar NTI boiler that I am learning.

I am splicing into a small staple up zone and extending it 150' to a pair of SlantFin baseboard heaters.

So in order to purge the modified zone or in all likelihood all the zones after my modification please let me know if this is correct.

1. The circulator pump flow is down to the floor with two ball valves on either side and the hose connection with additional valve just below the pump.

2. The return loop is just to the right with a single ball valve before it connects back into the manifold.

Steps:

1. Turn off the boiler and let cool
2. Close the ball valves "Flow Side" before circulator pump on all zones except zone to be purged.
3. Close "Return" ball valve on Zone to be purged
4. Open hose connection with valve
5. Turn up PCV valve to initiate water flow

Does this sound correct ?

thanks everyone from a DIY !

Dave


Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,946
    edited August 2022
    Did you say that you are splicing a radiant loop (usually low temperature below 125°F) with a Baseboard loop of emitter (usually high temperature above 160°F), and you want to learn how to purge the system after the work is done?

    STOP right there, don't mix two types of heat emitters (Radiant stable up with Baseboard) on the sale zone, loop, or thermostat.

    If i read you incorrectly, please explain a little better
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • moots
    moots Member Posts: 35
    edited August 2022
    Hi Ed:

    The existing zone is staple up from the boiler at whatever temp makes it from the boiler output of 180. So yes I am adding a pair of SlantFin baseboard heaters on the same zone but 100' away upstairs. What is the issue with mixing these two types of heat ? Do I need a mixing valve then ? The original zone is maybe 150 square feet only.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,946
    edited August 2022
    This photo shows that there is a mixing valve on at least 5 of the zones. This means that the heat emitters are operating at a temperature lower than 180° boiler limit temperature.. In this illustration from http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf there is a diagram on how to get 2 temperatures. At least 5 of your zones are of the type pictured as Zone 2

    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,946
    If you try to get any heat from a Slant Fin baseboard emitter using the lower temperature than say 160°F on the coldest day of the year, you will be disappointed in the outcome.

    I am of course assuming that the "Staple Up" you refer to is radiant floor heat that usually operates at about 90°to 125° water temperature.

    Read the Zoning Made Easy to learn how your system operates. The Boiler instructions will not give you the information in that booklet because it assumes that the professional that installed the boiler already applied the equipment to your system design based on already knowing what is in that booklet.

    Hope this helps
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • moots
    moots Member Posts: 35
    edited August 2022
    Thanks for the education ED ! It's interesting that the five mixing valves are driving all of the downstairs infloor heat zones while the two zones that have no mixing valves are for the baseboard heater zones upstairs. I would have thought the infloor heat would be running wide open and the baseboards would be dialed down a bit with the mixing valves ?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,946
    After a close look at the mixing valves, there are some set at Max and at least 2 others set at about #3. This indicates that you may have different water temperature zones. Are all the zones Radiant Floor Heat?
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,946
    moots said:

    Thanks for the education ED ! It's interesting that the five mixing valves are driving all of the downstairs infloor heat zones while the two zones that have no mixing valves are for the baseboard heater zones upstairs. I would have thought the infloor heat would be running wide open and the baseboards would be dialed down a bit with the mixing valves ?

    That sound correct. So to get more Baseboard to another area, you can add it to one of the existing Baseboard zones. if one of the thermostats is not going to serve the new baseboard properly, then you will want to make a home run back to the boiler room and add some zone valves or another zone circulator to allow for a separate thermostat in that new radiator area.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,121
    @moots

    You also need the proper flow in addition to all the above. 1/2 " pex will be doubtful unless you make a new zone with it and even then the most you can expect is 15,000 btus
    EdTheHeaterMan
  • moots
    moots Member Posts: 35
    The mixing valves are on the max setting btw. The space I plan on heating is only 380 sq ft so creating a new zone sounds like the logical solution which unfortunately means expanding the manifold and adding another circulator. thanks for all the advice !