Interfacing Cross Manifold and Tekmar 369

Harold

I posted on this in the spring. Still am not sure what to do, and it is getting cold now.

Help would be appreciated.

Background.

All thermostats go to the multiple Tekmar 369s. 18 total thermostat connections from 3 369's.

The Tekmar design is to activate relays in the controller from thermostat demands from the house. The thermostats are Tekmar and they are 2 wire. They are all connected as required. Each set of two thermostats are switched by the attached thermostats. There is a common connection shared between each of the pair that provides the shared 24 VAC source.

This 24 VAC is always on. There is one power supply connection for every two relays.

The normal behavior of this configuration is to simply provide switchable power to each of the 6 (per Tekmar controller) outputs to valves on the manifold. The original configuration was a simple thermostat trigger in the Tekmar to provide 24 VAC to each activated conventional valve on the manifold.

So, there is a 24 VAC Tekmar relay for each manifold valve. From the Tekmar to the manifold, there is 24 VAC and common (ground).

Now the question.

The Cross Manifold system replaces the simple configuration above. The Tekmar continues to exist and do what it has always done.

Here is where my confusion occurs. The Tekmar relays want to drive the manifold valves with 24 VAC. The Cross Manifold wants an input from a thermostat. Maybe power.

There is no documentation on the internal routing of circuits on the CM. Actually virtually no decent documentation. It has input for a 24 VAC power supply that runs the controller. The connection identifies the hot and ground connection.

I have been unable to satisfactorily determine what goes on inside the CM device. My original contact with CM left me not understanding what is actually happening. They warned me not to apply power to the inputs for the valves. But these same connections can get 24 VAC from a red wire in the set of three provided as individual input points for a valve (Red, White, and Black [common]).

There appears to be a ground plane on the internal board that carries 24 VAC to the red valve control outputs of the CM controller. The instructions seem to indicate they want to supply CM 24 VAC to the external relay source to work with the CM controller.

It would seem to be a conflict. I don't really know which power source I should use. My best guess at the moment is to use the controller to power the Tekmar relay contacts. I do not like that approach. There may be some grounding issues.

A side note: I do not seem to be able to find the company anymore. Attempts lead only to "database error". I may have an abandoned product and a dead company. That would be a joy. No parts.

If anyone has done something like this, or has some input, I would really appreciate it.