Simscape custom component compiler having trouble solving a simple two thermal resistor equation

I'm trying to write a custom thermal component, the basis of which is formed by two thermally conductive elements. The component compiles but I get this error when I try and run it.

Number of equations exceeds number of variables. Click on any Simscape blocks identified below for more detailed diagnostics.

    component thermalresistivenet3
        %thermalresistivenet3

    % Move heat with electrical work.
    % More comments not shown in the interest of space

    nodes %conserving ports
     Th = foundation.thermal.thermal; % H:top 
     Tc = foundation.thermal.thermal; % C:bottom
    end

    nodes(Access=private)
     Tm = foundation.thermal.thermal; 
    end

    parameters
     Tini = {273, 'K'};   % Initial Temperature
     Km = {20, 'W/K'};   % Thermal conduction
    end

    variables(Access=private)
     qS1 = { 0, 'J/s' };% heat flux
     qS2 = { 0, 'J/s' };% heat flux
    end

    function setup  
        qS1 = {value={0,'J/s'},priority=priority.low};
        qS2 = {value={0,'J/s'},priority=priority.low};
        %Set all thermal nodes to the same initial temperature 
        Th.T =  {value=Tini,priority=priority.high}; 
        Tc.T =  {value=Tini,priority=priority.high}; 
        Tm.T =  {value=Tini,priority=priority.high};

    end

    % Parameter validation.
    branches
     qS1 : Tc.Q -> Tm.Q;
     qS2 : Tm.Q -> Th.Q;

    end
    
  equations
   assert(Th.T > 0)
   assert(Tc.T > 0)
   assert(Tm.T > 0)

   %This is simply two thermal resistors connected to three thermal nodes. 
   qS1 == (Tc.T - Tm.T)*Km/2;
   qS2 == (Tm.T - Th.T)*Km/2;
   qS2  ==  qS1; %The heat flowing through one is the heat flowing through both

    end % equations

    end %component

In my mind this is a very simple thermal system. I want to write much more complicated thermal systems such as peltier devices. How do I model this system correctly?

Edit, if I remove the heat flow from the equation and set the equations equal to each other, I also run into a problem:

(Tc.T - Tm.T)*Km/2 == (Tm.T - Th.T)*Km/2;

Number of variables exceeds number of equations. Click on any Simscape blocks identified below for more detailed diagnostics. ThermalStackPeltierDebugsinglev2/thermalresistivenet3

Answer 1

[Steven]

The answer is simscape custom elements have terrible support and I found the answer on my own.

The answer is you don't write the heat flow part of the equations, this is taken care of by the branches. So the branches are an extension of the equations.

You only need these equations: qS1 == (Tc.T - Tm.T)*Km/2; qS2 == (Tm.T - Th.T)*Km/2;

The branches take care of the qS2 == qS1;