Original A/C thermostats

[oscarvan]

Seller says they are very finicky and it takes a while to dial them in. From what he's describing the "spread" is too large on the on/off

Are they adjustable? Some home thermostats I've worked with were.....

[racclarkson@gmail.com]

Could be fan is intermittent vs continuous. Could be thermistor location for starters.

[oscarvan]

They're running just fine. It's setting the thermostat to get the desired temp in the living space. Finding the right spot on the dial so to speak. Like I said the on/off spread seems a little large as in 5-6º versus 2º. Again, I've seen it adjustable on residential thermostats, is it on these?

[Briankinley2004]

Yes the temperature differential is more than newer digital stuff. That being said there was a recent post somewhere about compressor issues with newer thermostats on boats. Something about the heat gain being so rapid and a one degree TD caused issues with the compressors unless they had a built in re-start delay. I don't have any real complaints with my original's 1985 thermostats. Its typically so hot here we run them down low anyway

[Pascal]

Best money I spent 18 years ago when I bought mine was concerting the ACs to electronic controls.

[miboatnutz]

They're running just fine. It's setting the thermostat to get the desired temp in the living space. Finding the right spot on the dial so to speak. Like I said the on/off spread seems a little large as in 5-6º versus 2º. Again, I've seen it adjustable on residential thermostats, is it on these?

If you're referring to the original 110 volt Honeywell thermostats then yes they are "finicky". All four of them on our boat do the job, but we actually have to dial down well past the desired temperature in order to get what we want.

As an example, in the main salon, if I want 72 degrees I have to set the thermostat at around 65 degrees. It's a little better in the forward cabin/galley as a 68 degree set point gets me 72 degrees. The worst is the master stateroom where I have to dial down to something like 63 degrees to get 72 degrees.

Yes there is an electro-mechanical adjustment on each thermostat but after messing with them for hours, I finally gave up and simply dial down as needed.

Replacing the thermostats with digital controls is on the list for next year.

[oscarvan]

OK, that answers my question thank you.

[jim rosenthal]

Best money I spent 18 years ago when I bought mine was concerting the ACs

to electronic controls.

Strongly agree with this. There is NO comparison to how the AC units work with digital controls versus the old analog ones. Now, they probably have them so they talk to your iPhone... mine don't do that, but they are worlds better than the original controls.

[SKYCHENEY]

Replacing with Coastal Climate Control FX1 is fairly easy and inexpensive.

https://www.coastalclimatecontrol.co...egory=25823691

[Photolomy]

They're running just fine. It's setting the thermostat to get the desired temp in the living space. Finding the right spot on the dial so to speak. Like I said the on/off spread seems a little large as in 5-6º versus 2º. Again, I've seen it adjustable on residential thermostats, is it on these?

What year yacht is it? It sounds like they are talking about the original mechanical controls. Mine still has these, and yes, they are finicky. There is no dial to speak of, just three knobs. One knob turns the unit on. The next knob is a potentiometer that controls the fan speed. And finally, the third knob controls the temperature. If you have ever stayed in a hotel with an AC unit on the wall and a Warmer / Cooler knob, it is just like that, and just as bad.

The control is coarse due to a few reasons. The mechanical nature of the controls. The stiffness in the temperature knob. The fact that the temp is controlled via a sensor located in the air handler, which means the fan is always running. And the fact that boats are difficult to cool due to them sitting in the water and having not much in terms of insulation. Almost like cooling a car.

I have woken up in the middle of the night sweating because I adjusted the knob to be less cold but went too far and put it in heat mode. There isn't a lot of difference, at least on the control in my master. I thought about cleaning them up, but they are quite "manufactured" and not something easily adjusted or restored.