WA Control Announcement
Improved WA control to replace MA control beginning Aug. 1st, 2021

Heatco is excited to announce the launch of the improved 5:1 modulating WA control system for our modular duct furnace product lines. This control features the same fully-linearized modulation while achieving a condensed gas train footprint.
 
The new WA control system incorporates a ModCombo gas valve that combines the operation of the modulating gas valve and the safety shut-off valve all into one valve body. This reduces the gas train footprint by replacing the current modulating valve and safety shut-off valve to a single ModCombo valve. 
"MA" Control Gas Train
"WA" Control Gas Train
The ModCombo valve also reduces the number of locations for gas pressure adjustment. There is only one location to adjust for both the high fire and low fire manifold pressure.
 
Conversion in the field from one type of gas to another is also easier and more economical. The new ModCombo valve is used for both Natural and Propane gas by the addition of an electrical jumper. There is no longer a need to replace the modulating valve and/or regulator springs.
 
The operation, control logic, and adjustability of the MA control remains the same in the improved WA control, as do all control board electrical components, signal voltages, and signal wire terminations.

Click the links below to view WA wiring diagrams and Sequence of Operations on the Heatco website:
We are excited about the improved performance and capability of this new modulating control system, and we look forward to sharing more exciting products with you in 2021.

500/600 Product Update
In an effort to offset rising component costs and move to more readily available components, Heatco is changing the way we build our series A and B, 500 and 600 “TS/TN” Two-Stage and “WA” 5-to-1 modulating units. In the past, these units have used 1” gas valves and a standard single section manifold. Now, they will be built with split manifolds and utilize parallel 3/4” gas valves.