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13. Modulating Gas Valve (MGV)
Units equipped with optional modulating gas valves (MGV) contain two modulating gas valves in addition to two standard
gas valves.
13.1. Operation
The M2 will control modulating gas valves to maintain 110°F (default) discharge air during the heating cycle. The left heat
section will operate when 25−50% of nameplate heat is needed. Both heat sections will operate when 50−100% of the name-
plate heat is needed.
The normally open MGV will allow full heating capacity should the MGV fail.
13.2. Testing
Use the options given under the Prodigy "SERVICE/TEST" menu to run high or low capacity output.
13.3. M2 Output
The M2 0−10VDC output to the MGVs increases to modulate valves further closed during a reduced heating demand. The
M2 0−10VDC output to the MGVs decreases to modulate valves further open during a higher heating demand.
Heating Demand
Reduces
Heating Demand
Increases
506457−01 05/10
M2 Output to MGVs
Increases
M2 Output to MGVs
Reduces
Page 58
13.
MGVs Modulate
Further Closed
MGVs Modulate
Further Open
Modulating Gas Valve (MGV)
Heating Output
Lowers
Heating Output
Increases
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