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GypsyArtist · 03-24-2025, 04:13 PM

I have a 2005 Itasca Suncruiser with a Coleman Mach heat pump.

The model number of the heat pump is 46515-811. I believe it has been replaced at some point. The user manual that I have has a date of 9/30/16. I'm having a problem getting both cool air and heat. It turns on, and the fan blows air, but neither AC or heat comes out. When it's turned to AC, there's a kind of buzzing sound coming from the unit outside. No sound when it's turned to heat.

David 70 · 03-24-2025, 06:39 PM

They had problems with the thermostats on the units. Does the propane furnace work? If not, then I would guess the thermostat. I have them go bad on two different Winnebago's I've had. The first one I sold before I got around to replacing it. The present one I pulled the panel off that had the thermostat on it and in the wiring to the thermostat there was a "filter" in the line. It is an electronic filter to suppress any interference with the radio or other electronic equipment. I took it out of the line, and it has been working fine so far. It has plugs that just fit the wiring and after removing it I just plugged the wires back together.

Ray,IN · 03-25-2025, 12:41 AM

Yep, that is the new model to replace all other models, it's the only one sold today.
Here are the compressor cross-over numbers: https://myrvworks.com/wp-content/upl...el-Numbers.pdf

The trouble-shooting procedure is the same for most different model numbers. Take a look at this model 6535 service manual. It has an excellent trouble-shooting section that covers both the unit and thermostat.
That buzzing sound could be a bad start capacitor, which can be tested. When in A/C mode, only #1 compressor can be operating, but in heat mode both compressors run when heat is called for.

GypsyArtist · 03-25-2025, 04:36 PM

The propane furnace works fine, so I'm thinking it's not the thermostat.

I'm glad to have the 6535 service manual. Thank you! It has good diagrams, and information. I didn't realize it would be the same manual. I also found another really good posting from 2018 that talks about replacing a bad starting capacitor. I can test that, and see if it needs replacing. They apparently have a kit for that.

The buzzing sound seems to be coming out of the compressor area. Would that make sense if the capacitor is bad?

Ray,IN · 03-26-2025, 06:21 PM

This document by member "Duner" might prove helpful: https://www.irv2.com/forums/download...do=file&id=435
Although the 6535 and 6515 have the same components, they might be configured in a different layout.
I also have the electrical diagram for the wiring, should you need a copy, but normally it's pasted to the inside of the removable access panel.

If you plan to keep this MH for a long time, you might consider this modification: https://www.winnieowners.com/threads...ctable.729580/