Mine pulls air in from the side of the coach and blows it down through the floor of the bay. Do you have a hole in the bay floor for it to blow out? Sound like you need to change the rotation of your fan motor.
Everything I have seen pulls air through coil (air is cooler ) then past compressor to cool it down a little, properly charged and working unit will have cold vapor returning to the compresor to help cool it down
Coming back to the saga but this time I need to get some heat going - put it off since the last time I worked on this it was 100F outside… I did some forum searching and was reading through Jeff’s account trying to glean some info from it (Jeff was SO helpful with getting the AC running and I think he finally gave up on me…), After reading Richard’s response it finally dawned on me that the thermostat controls the kick fans not the AH directly - and I hope I read that correctly. I’m spending some time to get my converted to 24-volt SCS basement system and Ecobee thermostat to control the AquaHot unit…
From Richard: “As shown in Jeff’s pic, if a Tstat has the heat function, it is usually the white wire or terminal. It will connect to yellow with red stripe wire. This turns on the fans for the kick heaters. It does not turn on the Aquahot as others have stated.”
If I am reading this correctly the wire going to the thermostat (white that I think goes to yellow/black striped) and then down to the AC unit relay goes to the AquaHot to only turn on the kick fans not the Circulation Pump or the AquaHot itself. Am I thinking about this correctly? So I should be able to run a hot-wire from the thermostat, out the window to the relay on the AH and get the circ fan to come on? This kind of makes sense since the AH is basically an on/off switch that heats the tank up and then there is another circuit that kicks on the circ pump… Maybe I’m confused…
The picture shown is for the REAR TStat, with yellow/black… I can’t find the one for the FRONT TStat… It looks like the wire to the from TStat is solid yellow…
Not knowing what you have done as part of the control system rework.
The switches at the microwave turn the electric and diesel heat sources on the aquahot. The thermostats turn on the kick heater fans and the circulation pumps for one of the three zones. The tstat outputs a 12v pos signal. The aquahot uses a ground signal to activate a zone. Hence the use of the relay.
My guidance is use a voltmeter to determine if the tstat is producing 12v pos on the term marked W for white. Now look at the color of the wire connected to that terminal.
Go to the aquahot and find that wire.
Is it 12v pos? Is it connected to a cube relay?
Richard and Rhonda Entrekin
95 Newell, 390 Ex caretaker
99 Newell, 512 Ex caretaker
07 Prevost Marathon, 1025
Maverick Hybrid Toad
Inverness, FL (when we're home )
I have converted the AC system to 24-volt thermostat and relays so I would need to wire in an interim relay to make the 24 to 12-volt jump to the AH unit. Thank you Richard! I understand what the switches at the microwave panel do and they are working properly as I can turn on the 110v electric (I only have 30amp in the building) and it works fine.
I did test the continuity and cannot find the wire for the life of me…
W1 = heat on the TStat which is a yellow/black wire on the rear TStat and a yellow wire on the front TStat.
Does the yellow (W1 from TStat) go directly to the AquaHot unit or does it go to the SCS Basement unit board first?
I have been trying to check continuity using a 20’ 18ga wire from the rear AC (and the front AC) down to the Aquahot and also to the AC units but cannot get any tone out of it.
I know the continuity tester and wire is good because when I touch the ends together I get a tone (I know enough to know how to do this part)… I’m baffled as to where these wires from the TStat end up. I know the smaller gauge wires got directly to the SCS AC in a bundle that is twisted into the side of the AC unit via a bung of sorts to make the connections and they are working fine to run the AC units.
The pictures attached are the AH board/labels with the yellow/black for rear heat and yellow/red for front heat…; and the original 12-volt TStat; the new TStat is an Ecobee with two stages for the AC.
Look at your first picture. Look at the labels and wire colors on the top of the terminal strip.
Now look to the immediate left of the terminal strip and you will see the relay to convert 12 Pos to ground. The wire from the tstat is going to the cube relay.
Forget the wire tracer. There is a reason I suggested you do the following items.
Check the back of the tstat to ensure that it is putting out 24V. I think it may now be 24V AC not DC with the conversion you did.
Now to the AH and look at those wire colors and use the voltmeter to confirm voltage. Remember you are looking for voltage going into the cube relay. If you measure at the terminal strip you will get NADA, because AH is looking for a ground on those terminals to activated the zone.
I think you are going to have to replace the cube relays with ones that have a coil compatible with the voltage and AC ? DC? That your tstat is outputting.
Just for giggles, take a jumper wire from a ground source and touch it to one of three terminals for the three zones. The pump should activate, and the kick fans inside should activate.
Richard and Rhonda Entrekin
95 Newell, 390 Ex caretaker
99 Newell, 512 Ex caretaker
07 Prevost Marathon, 1025
Maverick Hybrid Toad
Inverness, FL (when we're home )
(01-30-2026, 04:46 PM)pairodice Wrote: I have converted the AC system to 24-volt thermostat and relays so I would need to wire in an interim relay to make the 24 to 12-volt jump to the AH unit. Thank you Richard! I understand what the switches at the microwave panel do and they are working properly as I can turn on the 110v electric (I only have 30amp in the building) and it works fine.
I did test the continuity and cannot find the wire for the life of me…
W1 = heat on the TStat which is a yellow/black wire on the rear TStat and a yellow wire on the front TStat.
Does the yellow (W1 from TStat) go directly to the AquaHot unit or does it go to the SCS Basement unit board first?
I have been trying to check continuity using a 20’ 18ga wire from the rear AC (and the front AC) down to the Aquahot and also to the AC units but cannot get any tone out of it.
I know the continuity tester and wire is good because when I touch the ends together I get a tone (I know enough to know how to do this part)… I’m baffled as to where these wires from the TStat end up. I know the smaller gauge wires got directly to the SCS AC in a bundle that is twisted into the side of the AC unit via a bung of sorts to make the connections and they are working fine to run the AC units.
The pictures attached are the AH board/labels with the yellow/black for rear heat and yellow/red for front heat…; and the original 12-volt TStat; the new TStat is an Ecobee with two stages for the AC.
Adrian
As Richard said, you need to change out the two aqua hot relays to 24vac coils to make your heat work. Its a fairly simple wire for wire swap. 2 wires go to the coil and 2 wires will be switched to make the aqua hot come on. Remember 85 and 86 on the old 12v bosch relay are the coil so you need to put that on the coil (#1 & #3) on the new 24vac relay. The other two wires are going to go to the #2 and #4 terminals on the 24vac relay, that is a normally open contact.
Here are the 24vac relays I used in place of the 12v bosch relays that are there now: https://a.co/d/bFDrxBA
Thank you Richard and Jeff! I know Jeff sent me some pictures of the relays I needed but I immediately lost it… I will try to get to the warehouse and try your directions today if the roads are clear. I have 90380 relays not 90370… will have to order some…
Sorry I’m so dense when it comms to these things but I’m learning as I go.
Thank you Richard and Jeff! I know Jeff sent me some pictures of the relays I needed but I immediately lost it… I will try to get to the warehouse and try your directions today if the roads are clear. I just happen to have a bunch of 90370 relays that Jeff suggested :-)
Sorry I’m so dense when it comes to these things but I’m learning as I go.
Progress! Mostly… I think I have the wires connected correctly but when I try to attach the 12-volt wire (yellow/black for bedroom - going to the labeled terminal strip) the aquahot comes to life and the pumps start running but I have not turned on the Ecobee yet! The yellow/black wire IS connected to the Ecobee. Maybe I have the two yellow wires backwards… will it hurt anything to just switch them? Not sure why the yellow/black wire is sending out 12-volts but I checked it with my meter and it was…
)
