Max95428 Posted December 2, 2020 Share Posted December 2, 2020 In my 02 Executive 40 PBT the fan speed for the heat exchangers from the kitchen forward (3 in total : kitchen, living room and cockpit) has dropped to almost nothing, it won’t even blow out a candle. These units are connected to the new a/c unit with the 10 button controller. A few days before this I noticed that the fan speed on these heat exchangers was varying considerably several times a minute. The bedroom fan and the one in the bathroom are still working fine, both connected to the rear a/c unit (original). I have two dometic penguin a/c units with heat pumps. Any insight on what might be wrong? Thanks in advance. Link to comment Share on other sites More sharing options...
Chuck B 2004 Windsor Posted December 2, 2020 Share Posted December 2, 2020 Usually if a fan speed varies like your does, its because of lack of grease/oil on the shaft that holds the bearing or bushing. Is that discussed in your manual? Does the annual PM of the unit cover that? When is the last time you had your annual PM done? Nothing lasts forever, its around 8 years old. JMHO, Chuck B 1 Link to comment Share on other sites More sharing options...
Ivan K Posted December 2, 2020 Share Posted December 2, 2020 In our setup the power to each zone's fan is coming from a large relay in the AH enclosure and the fans are in parallel to each other and the connections are made with a twist-on cap behind each of the fan pairs on registers. Could be that the relay or ground is compromised in the enclosure or the next near twist connection is loose. Unlikely that all the fans are failing at the same time but I have already replaced a couple of them under the sofa. Checking voltage output at the fans should give a hint. Getting to the relay would take some disassembly of the AH cover. In our case, the type of thermostat would not make a difference as long as the relays get activated. Your circuit diagram might show which of the registers is first in the chain and if all of the fans are effected, that would be the place to start looking for voltage drop and bad connection. Link to comment Share on other sites More sharing options...
Frank Bergamo Posted December 2, 2020 Share Posted December 2, 2020 Check to see if new thermostat has fan speed adjustment. The 5 button thermostat has auto/high/low. Don’t know about 10 button one. Hope this helps. Link to comment Share on other sites More sharing options...
ktloah Posted December 2, 2020 Share Posted December 2, 2020 I would check to see if fan speed is adjustable as Frank has posted. The new 10 button thermostats should have this...if it was working fine before you swapped out units, then I would start there first...good luck Link to comment Share on other sites More sharing options...
amphi_sc Posted December 3, 2020 Share Posted December 3, 2020 18 hours ago, Frank Bergamo said: Check to see if new thermostat has fan speed adjustment. The 5 button thermostat has auto/high/low. Don’t know about 10 button one. Hope this helps. Huh? On my coach the "fan speed" setting the thermostat controls the fan in the roof unit only. It has nothing to do with the AquaHot registers. In fact, my bedroom zone and bathroom zone only have 1 unchangeable speed while the roof units have high and low (I still have the 5 button thermostat) where auto just selects between high and low speed. The kitchen AquaHot zone does have 3 speeds (high/med/low) controlled by a multiplex switch on the wall where the kitchen lights, water pump, and AquaHot electric / diesel, etc, are located. Although the kitchen zone also runs the register at the front dash, that register is also only one speed and the Hi/med/low setting on the multiplex switch has no effect on that front dash register in the front (kitchen living room) zone although it blows based on the front kitchen zone cycle. As far as I know, the thermostat connects to the roof units which then send only a simple on/off "furnace" signal via a wire pair to the basement AquaHot. I'd probably pull the cabinet drawers/floor and see about lubing the fan motor of the affected registers and the wire connections there. YMMV as I'm a Beaver built by Monaco, and not a "true" Monaco. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted December 3, 2020 Share Posted December 3, 2020 Are you sure they ever blew very hard ? Does the other zones blow noticeably harder ? My registers don't blow very hard to begin with, very soft. If you have pets, hair as well as dust may have collected on the back side slowing the air It doesn't seem likely that 3 fan motors would all slow down at the same time which which points toward something common to all 3. Something causing low voltage to that zone could cause all 3 to slow, a connection upstream maybe. Like Al above I'm pretty sure your thermostat just controls the temp and off & on, not fan speed of the Aqua Hot Link to comment Share on other sites More sharing options...
Max95428 Posted December 3, 2020 Author Share Posted December 3, 2020 Thanks for all the replies . Upon further investigation I find there is a difference in the way the a/c unit and aqua hot unit works depending if I am connected to shore power or using the batteries only. The fans in the cozy 2 heat exchangers are 12 vdc as is the aqua hot ignition. When using batteries only ( inverter is off ) the fan speed is very weak from the kitchen forward which has the new 10 button controller that is necessary with the new dometic penguin a/c with heat pump. The bedroom and bathroom fans are strong ( will be checking to see if they are the same model number, amps and volts as the ones in the other heat exchangers. Now when I connect to shore power the aqua hot setting in the new 10 button controller will only work if the fan speed is set to auto. If I change the fan speed to low, med. or high the a/c heat pump comes on and aqua hot unit goes off. I called dometic and a technician told me it was supposed to work that way. When I am connected to shore power and am using the aqua hot unit this is when I get vacillating fan speeds. I am assuming this is because the fan speed is set to auto auto. However it is strange that the fans will not hold a certain speed for more than a few seconds. The bedroom and bathroom fans speed remains unchanged whether connected to shore power or using batteries only Link to comment Share on other sites More sharing options...
David Pratt Posted December 3, 2020 Share Posted December 3, 2020 Gentleman, I have been following this discussion and all the info that you are sharing and it is not only confusing, but it is wrong. If your coach is equipped with the Aqua Hot System you should go the the AquaHot site and download the Operator's Manual, Service Manual, Installation Manual and Parts Manual for the Specific Unit installed in your coach. You will be amazed at what you will learn about this great, simple System. Locate the Electronic Controller(the Black Box) mounted on the wall or ceiling in the bay next to the AquaHot Boiler and you will see the Status Lights. In your Owners Manual it will tell what each one represents and how to reset the System if you have a Low Voltage Indication All of the Fans that are attached to the Heat Exchangers are controlled by the Electronic Controller (the Black Box) mounted on the wall or ceiling in the bay next to the AquaHot Boiler. The only thing that your AC/heat pumps control is the temperature that you set on the thermostat telling the Aqua Hot when to turn on and provide heat for the selected Zones. There are no separate relays, fan speed controllers or anything else that controls the Heat Exchanger fans. Everything that is part of the Aqua Hot System is CONTROLLED by the Electronic Controller. Access the electronic Controller and remove the cover. looking straight at the Circuit Board you will see four Connectors with lots of wires attached. On the top of the board, the connector on the left-(JP1) has a twenty wire loom connected to it. On the right -(JP3) there will be a sixteen wire loom connected to it. On the bottom left on the board there is an eight wire loom -(JP2) connected to it and on the right side there is a seven wire loom-(JP4) connected to the board At the bottom of the Board the terminal-(JP7) is the Chassis Ground from the coach and Terminal -(JP6) is the 12VDC primary power source coming from the coach. There should be a Jumper between Terminal (JP6) and (JP5). When you look at the electronic controller Board you will see that the terminals are clearly marked on the board what each wire is connected to and what circuit it controls. The long Twenty Wire Connector on the left upper side of the board is where the heat exchanger fans and the circulation pumps are controlled and where the input from your AC thermostats are connected. There is the ability for the Electronic Controller to control three heating zones, (Five Heat Exchangers). Zone 2 can control up to three Heat Exchangers. All the wires from the wire looms are held into the connector by screws, it is very simple to pin-out each circuit. each fan will have a + and - wire coming from the board going directly to each fan/heat exchanger. The two wires for each fan/heat exchanger connect directly from the board to the fans. When the fans are running you can check the voltage output at the board using a multi-meter connected to each fan output + and - wire. The voltage output at the fans should match closely what is measured at the board. There is a trouble shooting section in your manual that might help. Once you Isolate the issue you might want to call Roger Burke or Aqua Hot and get more technical help. I have included the control panel pics . AHE-600-Panel.pdf CB Connections.pdf Electronic Control Board.pdf Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted December 3, 2020 Share Posted December 3, 2020 What about the over head lights, do they flicker or dim when the fans vacillate? If you can get to the fan wiring I would run a temporary 12v wire directly to see if that eliminates the slowing down . It would also be interesting to see if the voltage at the fans varies as the speed changes. He hasn't said his aqua hot model but in an 02 yr model he probably doesn't have an electronically controlled unit Link to comment Share on other sites More sharing options...
ktloah Posted December 3, 2020 Share Posted December 3, 2020 I believe that the question was about the Aquahot 100-02S...there is no control panel with lights...someone already downloaded the correct manual for his model....good luck Link to comment Share on other sites More sharing options...
Max95428 Posted December 3, 2020 Author Share Posted December 3, 2020 Yes my aqua hot unit is model # AHE-100-02S Link to comment Share on other sites More sharing options...
Ivan K Posted December 3, 2020 Share Posted December 3, 2020 There are zone relays with AHE-100-02S just as I mentioned and they control the zone fans... 1 Link to comment Share on other sites More sharing options...
Max95428 Posted December 3, 2020 Author Share Posted December 3, 2020 I had my unit serviced summer of 2019 and it was not used until just a few weeks ago. Unfortunately the closest certified aqua hot technician is 3 hours away at $150/hour. He has limited parts, it took 3 trips that summer to get it working properly, so I hope I can get this figured out without needing him. Thanks again for all the help Link to comment Share on other sites More sharing options...
Frank Bergamo Posted December 3, 2020 Share Posted December 3, 2020 Max, on my 2002 Beaver Marquis each heat exchanger had a off/hi/low switch. Might be worth a look. Hope this helps. Link to comment Share on other sites More sharing options...
David Pratt Posted December 3, 2020 Share Posted December 3, 2020 I take back my POST! Link to comment Share on other sites More sharing options...
Max95428 Posted December 3, 2020 Author Share Posted December 3, 2020 No worries David, everything helps. I did look for that black box though. I am sure a great improvement for the aqua hot system. It really burns you though when companies make improvements that aren’t Link to comment Share on other sites More sharing options...
96 EVO Posted December 3, 2020 Share Posted December 3, 2020 36 minutes ago, Max95428 said: It really burns you though when companies make improvements that aren’t Aqua Hot has most certainly accomplished that 😠! Link to comment Share on other sites More sharing options...
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