Madness with Weil McClain CVT gold


Old 12-11-16, 12:08 PM
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Madness with Weil McClain CVT gold

I have been battling this thing for over a month. I've gotten it pretty well fixed but this last issue has me stumped. My understanding is that for space heat the three way valve actuator drops and pushes down on the valve to allow water to circulate through the house and heat. In my case it is the opposite. With the actuator in place the control board does try to do just that, but with the valve/actuator in the down position water doesn't flow to the baseboards. The circulator will be running the boiler up to temp and the baseboards cold. As soon as I remover the actuator and the valve pops up the baseboards get as hot as can be.

The install is from 2007 or 2008. I see there was a service bulletin that required the three way valve to be spun 180 degrees. Based on serial number that does not apply to my unit. I did just install a new cartridge in the three way valve as it wass weeping. Is it possible that the cartridge is for the updated valve orientation.

In any case my boiler will not heat the house with the actuator on. With it off I assume I'll be in short supply of domestic hot water as that is the function of the 3 way. To make domestic regardless of space heat demand so as not to get a cold shower etc.

Thanks in advance.
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Old 12-11-16, 12:25 PM
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Welcome to the forums.

You've left us the boiler model but nothing on the valves you're working with.
Old 12-11-16, 03:34 PM
Join Date: Nov 2011
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Do you mean Weil Mclain CGt? The CGt comes with the kind of 3-way valve you seem to be describing.

I don't know for sure so don't quote me, but I believe the "default" position for that kind valve is to allow hot boiler water to flow through the system supply piping, and out to the emitters, and then back through the return piping into the boiler.

The "event" that triggers the valve to change position occurs when the boiler water is too cool to provide domestic water from the coil. Upon such event,
the valve changes position and closes off the system return water port, which causes all the hot boiler water to be diverted directly back into the boiler instead of going through the heating loop.

It would seem a little strange to me that the valve would need to be "actuated" in order to remain in the default position. I would think it more likely that the opposite is true....that the valve is only actuated when the "event" occurs.

Obviously it's critical to install the valve in the correct position. Maybe you have some kind of installation/piping issue.

P.S. Do you have the installation/operation manual for the boiler?
Old 12-11-16, 03:46 PM
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Ahhh...... that makes more sense..... CGT.

There are a few manuals floating around but this is a good one.

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