New Baseboard on Venturi loop not working

Old 12-16-05, 05:14 AM
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New Baseboard on Venturi loop not working

I think I screwed up! I renovated a small room 8x12 which had a huge burnham radiator in it. The room used to be bigger. The supply is off a 1" loop to which a 1/2" Venturi T draws hot water to radiator. I replaced it with slant fin 30 baseboard that runs about 18 feet along 2 walls.
Well I guess the Venturi cannot draw enough hot water to through the baseboard because it does not work!!! Is it possible that the venturi got clogged? The line had been capped for about 4 months.

I'm looking for options to make it work or do I have to rip it out? Maybe a small circulator and a thermostat?

Any help would be appreciated. Thanks
Old 12-16-05, 10:51 AM
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Venturi Loop


Don't worry, you can make it work; first make sure you put the venturi valve in correctly, it's very easy to put them in backwards; most of them have "supply" , "return" or an arrow stamped on their housing; if you put it in at the riser pipe that feeds the new baseboard, the supply side of the valve has to shoot water into the baseboard; if you put the valve on the riser pipe that returns water from the baseboard, the valve has to suck water thru the baseboard by its venturi action; you can see this clearly if you obtain & examine an extra venturi valve.

Also make sure you've bled all the air out of the new baseboard (you did put in a bleeder valve on both sides, didn't you); a large air pocket will prevent water flow.

If the valve is in correctly, & you've bled out the air, & it still doesn't work, you can install a 2nd valve on the side that doesn't have one yet to force even more water thru the baseboard.

I'm assuming you have a standard install, where the baseboard is not looping UNDER the main supply pipe, to a basement, for example.

Consult the website below for an extended discussion with diagrams on venturi valve piping systems: click on the website's sidebar "Heating Q & A", then onto "Diverter tee Hot-Water Heating".

Last edited by Chimney Cricket; 12-16-05 at 11:12 AM.
Old 12-16-05, 01:02 PM
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Thanks for the reply Chimney Cricket.
I do know that the venturi is on the return side and was installed correctly.
These T's have been sheetrocked over already, trying not to have to open ceiling up, but will to add another venturi T on supply side if needed. I only installed 1 manual bleeder but it is on the high side about 1" higher than the other side. Is the other bleeder absolutely necessary. The loop is about 1' below baseboard.

Do you think I need to add the other bleeder?

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