I have a furnace , model MMHA-07OABHR-05 serie MMH)603-0049 when it started the cicle tha main valve cant input the gas to start , please i need the electric diagram, if you can send me it , thank you
Hi, as far as getting a schematic for this unit, I have had no luck at all. This can be almost impossible these days.. On this pack unit, check the sequence of operation to see why you have no 24 volts to the main gas valve, The combustion motor will start first. Make sure its on. See if this unit has a pressure switch and make sure it is closing. You can bypass it by jumping it out.If the pilot lights, and if the unit has a flame sensor, make sure the metal tip is clean to send a signal to the module to fire the gas valve. If you have a meter to check the voltage, this will tell you a lot. Sounds as though you have a safety open somewhere in the circuit. You can eliminate almost all of them by using a jumper wire to find which part is the fault. Very easy to trouble shoot with out a schematic, if you look at it when it cycles, you can see the sequence of operation. Check across the main gas valve when it goes through the complete cycle, from the M terminal, and C terminal for 24 volts. You may have a faulty gas valve if all other parts have 24 volts. Please let me know, and I can walk you through it.
A/C, & Heating Contractor
Nov 27, 2010 |
Intertherm P3RA-048K Air Conditioner