Riv 28 A/C

[g36]

Hi Cleve here's a link with instructions on 3 knob control. ,....https://www.tropicalmarineairconditioni ... -AH3KB.pdf

[g36]

Also here you go. Theres upgrades to digital controls that can be installed easily to replace your old 3 knob control ... The typical function of each knob was as follows...

The first knob was a function knob with Off, Start (sometimes labeled Fan) and Run positions...
The functions of each position were pretty much self explanatory except that the Start/Fan position ran the fan but also started the seawater pump so that you could look over the side of the boat to verify it was pumping water before selecting Run.

The Run position sent power thru the thermostat which then would decide whether to start the compressor in the cool, or heat mode depending on cabin temp, and the position of the thermostat knob...(more on that in a minute)

The second knob was a Variable Fan Speed control (not usually available at home)
It was useful at night for lowering blower noise to watch TV etc...(how low was low was adjustable but the control needed to be removed to adjust this parameter with a small screwdriver)

The third knob was the thermostat...
This was the most misunderstood function of this control because it had no temp numbers (It was also the hardest to explain to folks) Most would just crank it to it's coldest setting thinking that the further they turned it...The colder the air would come out...That's true in a way, but it's not a function of the control, and A/C does not work that way...I will try to explain...

Regardless of control setting or type...All R-22 A/C systems work on a 15 to 18 degree temp exchange design...Meaning that the air coming out of the discharge grill should be 15 to 18 degrees colder than what is going into the return air grill (if it's more, or less than that, there is likely a problem with the system or installation)

So if it's 90 degrees in the space being cooled...don't expect much colder than 75-72 degree air coming out the discharge with any R-22 A/C system...But as the room/cabin cools, that exchange is maintained, and the air continues to come out colder by 15 to 18 degrees of what goes in....Lower room temp=lower discharge air temp.

The thermostat tells the compressor when to run or not run, and energizes the reversing valve when reverse cycle heat is needed to maintain cabin temp of the setting on the dial (position of the arrow)...Generally speaking...A properly calibrated t-stat set with the arrow pointed vertical should maintain around 70-74 degrees cabin temp...Anything to the right is a colder cabin, and to the left of vertical is warmer...The T-Stat will allow the compressor to run until the cabin gets to the selected temp (on the knob) at which point it cuts power to the compressor until the cabin either warms or cools a few degrees, at which point it then again sends power back to the compressor/reversing valve as needed to bring the cabin back to selected temp.

These controls offered very little in system protection and thus it was not advisable to run the A/C system unattended for very long.