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paulfedex · 05-21-2017, 19:53

I have lived in my 1986 XL full time for three years now. I have three cruisair units that have always cooled effectively with no problem. Even now they are cooling effectively but this year the thermostats do not seem to cycle the compressors on and off as they used to. One notch on the knob is off and a millimeter further is on, but on all day and into the evening. So, I am reluctant to leave them on and unattended. What could the problem be? Two out of three units are acting in this manner. The thermostat knob amounts to no more than an on/off switch. I cannot find these for sale anywhere and not really sure if the switch itself is the problem.

Paul

davidbrady · (This post was last modified: 05-21-2017 21:24 by travelite.)

Hi Paul,

You'll probably need to get AAP on the phone. Sounds like you have a faulty thermostat. The early tstats were known to fail because they switch 120VAC and they get hot. They also have a 10' long capillary tube terminated with a large temperature sensing bulb that's mounted in the return duct. Could you have damaged the tube some how? Perhaps you can sight down the return duct to find the bulb to make sure it's still connected to the capillary tube? I think the capillary tube and bulb contain a liquid that expands and contracts at normal operating room temperatures. Sounds like the liquid leaked out making the temperature control ultra sensitive. Does the compressor short cycle?

paulfedex · 05-21-2017, 21:34

(05-21-2017 20:35)davidbrady Wrote: Hi Paul,

You'll probably need to get AAP on the phone. Sounds like you have a faulty thermostat. The early tstats were known to fail because they switch 120VAC and they get hot. They also have a 10' long capillary tube terminated with a large temperature sensing bulb that's mounted in the return duct. Could you have damaged the tube some how? Perhaps you can sight down the return duct to find the bulb to make sure it's still connected to the capillary tube? I think the capillary tube and bulb contain a liquid that expands and contracts at normal operating room temperatures. Sounds like the liquid leaked out making the temperature control ultra sensitive. Does the compressor short cycle?

Hi David,

Thanks so much for the info. No short-term at all. They just run all the time or none of the time. Interesting about the fluid in the capillary tube. Bulbs and tubes are there, but don't know about the fluid yet. Yes, they have always run a bit warm. The faceplate seems to act as a heat sink. So, this AAP place stocks these parts?

davidbrady · (This post was last modified: 05-21-2017 22:28 by davidbrady.)

Paul,

Although I haven't used them, I've heard great things about the folks and service at AAP. They are the CruisAir specialists of choice. I hope they have what you need because I believe upgrading to the newer SMXII remote thermostat requires a new compressor and control board. Let us know what you find out.

paulfedex · 05-22-2017, 00:09

Thanks again David. I will contact them this coming week and report back. I can use the a/c as is, but I would prefer it regulates more automatically. Won't be changing compressors or anything like that.

Paul

davidbrady · 05-22-2017, 14:33

Paul,

This place has some replacement thermostats and parts: http://www.nwmarineair.com/cruisair-heat...hermostat/

paulfedex · 05-24-2017, 00:03

Been checking on some more specific information. The part I need to replace is a rotary switch assembly that comes with capillary tubes: SA1-ZHB10. Not many of these around, but some of the yacht/marine places have them for anywhere from $470-535. I would need two.
Think I will place this project on the back burner for now.