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    Myson 7000 toekick heater (8 Posts)

  • Tom_A Tom_A @ 11:06 PM
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    Myson 7000 toekick heater

    I'm trying to install a toekick heater in our kitchen. we have an oil-fired boiler and baseboard heat which is a one pipe loop. (3/4") Kitchen is being reno'd and I removed about 10 feet of baseboard, (bypassed it in the basement keeping the loop correct)  to fit some pantry cabinets flush to the wall, and I'm trying to install the toekick heater in one of these pantry cabs. I followed the directions, and installed a monoflow tee on the supply side and a regular tee on the return and made sure the return is 12" from the monoflow tee. (photo attached). The unit is only a couple of inches above the main line.
    My problem is that the hot water doesn't seem to be flowing through the unit. the unit is always cold, although baseboards both upstream and downstream are toasty hot. The pipes going through the floor just before the flexible hoses are hot. I have isolating valves at the end of the flexible hoses that attach to the unit. I removed the unit, opened each valve into a bucket, have great pressure, and very hot water. when I hooked it back up, opened the valves and bled the air from the unit, it got hot for a minute, but not long enough for the fan to kick on, and then cold again. I was able to manually run the fan by switching to summer setting. I've tested the thermostat by heating the coil pipe with a lighter and it does kick the fan on when hot. I just don't understand why the water is not moving through the unit and what can be done to correct it. someone mentioned putting a shutoff valve on the main between the supply tee and return tee to force the water through which is a good idea to test it but I know I can't leave it closed or the downstream baseboards will be starved. Any ideas or suggestions will be appreciated.   Thanks.
  • There must be

    an air blockage somewhere in the branch piping.  Put that ball valve between the tees.  With it turned off, the water should push the air through.
    Often wrong, never in doubt.
  • icesailor icesailor @ 6:58 AM
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    You can't leave the valve in there permanently, pipe it right and it will work.
  • Steamhead Steamhead @ 2:15 AM
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    You got the tees backwards

    the Monoflo tee is supposed to be on the Return connection, pulling water thru the kicker. As it now stands, the Monoflo is trying to pull the water up the return from the main, and discharge the water back thru what is supposed to be the supply connection.

    Another way to do this is to use two 3/4"x1/2"x1/2" tees, reducing the pipe size between the kicker connections to 1/2". Two 1/2" pipes equal 1 3/4" pipe, so this would maintain the proper flow rate thru the zone.
    "Reducing our country's energy consumption, one system at a time"

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  • Tom_A Tom_A @ 2:48 PM
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    Monoflo tee

    Thanks. I'll switch them this weekend. Since I'll have the system drained, I'll put that ball valve in also just to have it there in case I need to flush the air through.
    Thanks to everyone on this site for being so helpful.
    I'll post back on Monday and let you know what happens.
  • Mark Eatherton Mark Eatherton @ 2:52 PM
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    Put in two venturi tees...

    Typically, if the radiator is below the main, OR if the device is a high pressure drop device (which most fan coils ARE...) it may be necessary to use two venturi tees. One on supply, and the other on the return.

    Also, you have to manually purge the air out of the FCU because the venturis can't generate enough pressure to self purge the branch.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Eric Eric @ 6:39 AM
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    the venturi or monoflow...

    tee should be installed as the return tee so it pulls from the kickspace heater. There would be a plain tee on the supply, the cone inside the tee would be larger on the supply end and smaller on the return end.
  • Paul48 Paul48 @ 3:50 PM
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    using 2, the one on the supply side is reversed, and will force flow into the line.The one on the return is installed normally, and would act as a venturi.
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