Installing Zone Valve Control

Old 08-02-16, 07:43 PM
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Installing Zone Valve Control


I have a Lochinvar Solution CBN180 boiler.

I have three high temp (180 degrees) zones running to baseboards and I have three low temp zones (about 120 degrees) running to in-floor zones. I have a high temp circulator for the high temp zones, a mixing valve, and another circulator for the low temp zones.

Coming out of the boiler, thereís the air separator, expansion tank, and make up water, then the circulator, then mixing valve, then three zone valves to baseboards.

After the mixing valve thereís a circulator and three zone valves to in-floor.

The high temp zone valves and circulator are wired to an RA832A relay and the relay is wired to the terminal block on the boiler.

The low temp zone valves and circulator are wired to another RA832A relay and the relay is wired to the same connections as the high temp zone to the terminal block on the boiler.

My first question/problem is that the wiring is a mess. Iíve cleaned up some of it but itís not pretty and troubleshooting is difficult. After some reading, it looks like a Taco ZVC406-EXP-4 will meet my needs better than traditional/old school wired zone valves. Plus provide some expansion for future DHW/wood boiler integration. Am I on the right track?

From what I read, the ZVC will support my setup, correct? I would be able to remove the two RA832Aís and my zone valves and thermostats would be wired to the ZVC, correct?

My second and major issue is when a high temp zone calls for heat, then a low temp zone calls for heat, the high temp zone becomes satisfied but the low temp zone is not, the boiler will short cycle. I get harmonics and high limit trips. High limit trips and short cycling is a problem whenever the low temp zones are running and the run time is quite a bit longer. So the boiler short cycles almost continuously.

Both zones return to a common return. When the in-floor zones are active, the water temp coming back is pretty cold. The boiler does have a built in low temp loop that prevents condensation.

Any recommendations to get around the short cycling?

Thank you very much, in advance, for any advice.


Old 08-02-16, 10:28 PM
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Welcome to the forums.

Not the pro here but a few well lit pictures of your setup and plumbing there would be very helpful.
Old 08-03-16, 05:35 AM
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First 10 pics

I tried to do a walk around.

The low temp loop is on the left against the wall and can be first seen in the 4th picture and the pex running into the floor can be seen.

Thank you again for your help!


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