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Heat

Hi All,

Quick question about the heat... When using the aqua hot for heat there is only one fan speed for the hot air correct? I do not see anywhere where there is a option for fan speed. 

When I select the heat pump I do see fan speed selections on the thermostat. I tried using the heat pump last night but it was 32 degrees...looking at the manual I believe that they don't work at that outside temp.

Thanks
Charlie

Re: Heat

Reply #1 –

Hi Charlie,

The Aqua Hot heat exchangers are single speed.  I have PWM speed controllers that adjust the speed of the fans individually.

Like these ...
Amazon.com: RioRandâ„¢ Upgraded 6V-90V 15A DC Motor Pump Speed Controller:...

These are 15 amp controllers, 3 amp are probably sufficient but they may be noisier (smoe people hear a bit of a hum from the controllers)

There is also a relay that controls power to the dash fan.  I added a switch to disable the dash fan when we don't want the extra heat or noise.  The heat causes the front thermostat to warm up more quickly and shut the AH heat off.  With the front blower off the noise level is lower, the other blowers (which are quieter) run longer and the heat in the LR is more uniform and has less variation.

See ...
Aqua Hot Dash Blower Fan Override

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Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Heat

Reply #2 –
Quote from: Roger & Susan in Home2 –
The Aqua Hot heat exchangers are single speed.  I have PWM speed controllers that adjust the speed of the fans individually.

Like these ...
Amazon.com: RioRandâ„¢ Upgraded 6V-90V 15A DC Motor Pump Speed Controller:...

I need to run a fan at 6volts and was planning to do PWM, but what do you think of a buck DC converter? Maybe it would be quieter without the PWM whine?  Amazon.com: DROK 090483 DC Car Power Supply Voltage Regulator Buck Converter...

Edit: The specs say PWM is 15khz and the buck regulator is 300khz.  Plus the buck regulator has an inductor on it.....so maybe it would be quieter?!?  It's past my knowledge base.
As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
1998 U270 34'

Re: Heat

Reply #3 –
Hi Roger,

Thanks for the info.... Installing the fan controller will it also speed up the fan from where it is now or it  will start at this speed and you can adjust down?

Thanks
Charlie

Re: Heat

Reply #4 –
The PWM controller will slow it down. The fans in the later AHs are pretty low power so it doesn't take much to control the speed. As I recall AH sells a pretty high priced speed controller that does the same thing.

We found that disabing the dash blower reduced the noise level by a lot. It makes watching TV easier even with the other AH blowers at full speed. My initial idea for slowing the blowers down was to add heat slower and longer which would help even out the temps throughout the whole LR.  For the most part shutting off the dash blower does the same thing since the front thermostat isn't getting blasted by the front blower.

I would do the front blower bypass first and see how that works for you.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Heat

Reply #5 –
All the 89 and up Marquis had four zone webasto fired hot water systems with larger squirrel cage motors than foretravel uses and fan controls on the edge of the counters in the governed areas.

More hot water from webasto burner.  Maybe not continious rated  as I did not use the showers?
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Heat

Reply #6 –
Quote from: Roger & Susan in Home2 –
I am not sure a voltage regulator would act as a variable speed controller.  I don't hear them, my wife does.  I also use one on a 5" computer fan in the front overhead spaces to provide positive ventilation.  It runs very slow and quiet.

PWM is just a type of voltage control. I'm going to ask some nerd friends and see what they say. Worst case, I'll just try it....or try both (since they are negligible in price).
1998 U270 34'

Re: Heat

Reply #7 –
In the long run after all the experimenting wouldn't it be cost effective to just upgrade the furnace to a 2 stage unit that's more efficient and already updated,and just enjoy the higher efficiency and quieter operation,and just go and enjoy RV'ing instead of trying to rebuild a dinosaur!,It's Your Time and Your Money,just sayin ::)
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Heat

Reply #8 –
There is no difference in the efficiency of going to a "new" 2stage unit. And, the burner and all the parts in the furnace of a new 2stage are the same as my current 40k model. I need a new motor anyway, so that solves that "cost" (the 2stage motor is actually cheaper). I found the 2stage valve for very cheap new off ebay. Other than that, the parts are all the same (I looked through the parts manuals). A new 2stage is $900 or so. I'd rather spend the money on diesel. Some watch sports, others like to figure things out and work the brain...to each, his own.
1998 U270 34'

Re: Heat

Reply #9 –
Quote from: Roger & Susan in Home2 –
The fan speed discussion was related to the heat exchangers used by the Aqua  Hot systems.  PWM controllers do not vary the voltage to control dc motor speed.  They pulse power to the motor at a constant frequency.


PWM is one technique for varying the power by varying the current and voltage. It's changing the average voltage (DC in this case). It appears smooth with little ripple because the switching frequency is high.

This guy explains better than me:
Quote
The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast rate. The longer the switch is on compared to the off periods, the higher the total power supplied to the load. Pulse-width modulation - Wikipedia

PWM can be used for AC VFD drives too...then the pulse goes postive and negative. DC all stays on the same side of zero, though.

1998 U270 34'

Re: Heat

Reply #10 –
Here's a good video on PWM explained.  I stumbled upon it today, while looking up something regarding testing components (power probe)  http://www.youtube.com/watch?v=5VGh1g2ovA8
1998 U270 34'