Author |
Message |
jackbombay Samba Member
Joined: October 19, 2007 Posts: 2723 Location: Eastern Idaho
|
Posted: Thu Apr 25, 2013 3:16 pm Post subject: Propex thermostat adjusting, moving the whole range downward |
|
|
In the propex photos thread I asked about adjusting the propex thermostat so that you can set the cabin temperature to lower than 50 degrees. As it arrived, the lowest I could set my thermostat was warmer than I wanted, if its 10* out I want to be able to set it to 40* to sleep comfortably without using any more propane and battery than I need. The range of the thermostat is about 50-80* F
It turns out you can replace a resistor in the thermostat to move that entire range downward, here is what Karl posted about it,
westyventures wrote: |
Ok. Thermostat adjustment folks:
"Changing R7 from a 12k resistor to a 15k resistor will lower the range slightly"
Let me know how it works out! |
I decided I wanted a bit more than a slight change, so I went with a 22k resistor, it is currently 80* in my van and with the thermostat maxed out the heater won't come on, so theres that!
I imagine you guys want to see some pictures, yea?
MAKE SURE TO PULL THE FUSE TO THE PROPEX BEFORE STARTING THIS!
The resistors, $.99 for 5
On the lower right you can see the resistor that needs to be changed out, the blue one right below the thermostat knob,
And here is the soldering iron I used, nice sharp tip, this soldering is as bad as say adding a remote temp sensor to a Prostar charge controller, but you don't want to be messy with the solder either.
And here is the resistor removed,
And the new resistor with wires bent and cut to match the holes in the circuit board,
And here it is soldered in,
I will report back with the new temperature range with the 22k resistor installed, I also picked up a 15k resistor if this dropped the range too low.
EDIT// I ended up with a 17.2k resistor (15k + 2.2k in series) and I think it is just right, in the evening when it cools down and I'm wearing shorts and a t shirt right when I think "its a little cool in here" I can get the heater to turn on if I turn the thermostat to the max setting. This is of course an extreme example as if I were really somewhere cold I'd just have more clothes on.
Where I live it is extremely cold so I will be able to test this to "get it right" any time of year, I will also be in some ~35 weather soon so I'll have info in a couple days... _________________
Gas struts to pop your top easily!
Pop Top strut kits now available for late Bay window Westies
Samba ad here.
DIY artificial rain gutters (ARGs)
Last edited by jackbombay on Mon Apr 29, 2013 2:53 pm; edited 1 time in total |
|
Back to top |
|
|
bluefirefly Samba Member
Joined: March 16, 2011 Posts: 438 Location: Calgary, Ab
|
Posted: Thu Apr 25, 2013 5:48 pm Post subject: |
|
|
Thanks a lot for doing it.
I need to check mine first and I'll certainly do it next month. _________________ 86 Syncro Tintop G60
work in progress ...as always! |
|
Back to top |
|
|
luVWagn Samba Member
Joined: February 21, 2008 Posts: 1340 Location: Snoqualmie (WA)
|
Posted: Thu Apr 25, 2013 6:30 pm Post subject: Re: Propex thermostat adjusting, moving the whole range down |
|
|
jackbombay wrote: |
The resistors, $.99 for 5 |
I'm rusty - does the blue indicate 1/2 watt, and the tan indicate 1/4 watt - in which case your new resistor would be under-sized? Or is the blue/tan irrelevant in this case? _________________ '91 Syncro 16 Reimo Hightop Conversion, eTDI |
|
Back to top |
|
|
tangojeff Samba Member
Joined: February 20, 2005 Posts: 209
|
Posted: Thu Apr 25, 2013 7:34 pm Post subject: an easy way to replace a resistor on a circuit board |
|
|
The USN taught me a technique for changing components on circuit boards back in the 60's. To replace a resistor, first cut it out w/ small diagonal cutters and be sure to leave most of its two leads still soldered to the board. Next bend them straight up so they can become 'Stand Off Posts" for the replacement part. Now wrap the leads of the new resistor around these two "posts". Solder these together and trim off the surplus. Check the rear of the board. By using less heat, the original solder point probably still looks the same. And no heat damage occurs to the circuit board. |
|
Back to top |
|
|
WLD*WSTY Samba Member
Joined: November 04, 2009 Posts: 438 Location: Arizona
|
Posted: Thu Apr 25, 2013 8:29 pm Post subject: |
|
|
Nice mod, thanks for the writeup! I'll be doing that upgrade soon.
Now, who has the mod to allow the circulation fan to run for a couple of minutes AFTER the burner shuts down? My home furnace does that, moving the residual heat out of the furnace into the house. I've found that the Propex has that heat left over too, and I can manually flip on the fan as soon as the burner shuts down and get warm air for 2-3 minutes. Now to find a way to do that automatically. I figure that should improve efficiency by at least 10%. _________________ '82 SyncroWesty, the first ever conversion.'06 Subaru 2.5L |
|
Back to top |
|
|
jackbombay Samba Member
Joined: October 19, 2007 Posts: 2723 Location: Eastern Idaho
|
Posted: Fri Apr 26, 2013 6:53 am Post subject: Re: Propex thermostat adjusting, moving the whole range down |
|
|
luVWagn wrote: |
jackbombay wrote: |
The resistors, $.99 for 5 |
I'm rusty - does the blue indicate 1/2 watt, and the tan indicate 1/4 watt - in which case your new resistor would be under-sized? Or is the blue/tan irrelevant in this case? |
the color bands, according to the radio shack package, indicate the resistance of the resistor and the last band indicates its tolerance. according to the radio shack guy the size of the resistor was the only indication of its wattage. _________________
Gas struts to pop your top easily!
Pop Top strut kits now available for late Bay window Westies
Samba ad here.
DIY artificial rain gutters (ARGs) |
|
Back to top |
|
|
jackbombay Samba Member
Joined: October 19, 2007 Posts: 2723 Location: Eastern Idaho
|
Posted: Fri Apr 26, 2013 6:56 am Post subject: Re: an easy way to replace a resistor on a circuit board |
|
|
tangojeff wrote: |
The USN taught me a technique for changing components on circuit boards back in the 60's. To replace a resistor, first cut it out w/ small diagonal cutters and be sure to leave most of its two leads still soldered to the board. Next bend them straight up so they can become 'Stand Off Posts" for the replacement part. Now wrap the leads of the new resistor around these two "posts". Solder these together and trim off the surplus. Check the rear of the board. By using less heat, the original solder point probably still looks the same. And no heat damage occurs to the circuit board. |
There is plenty of space behind the propex thermostat cover so this technique would work! _________________
Gas struts to pop your top easily!
Pop Top strut kits now available for late Bay window Westies
Samba ad here.
DIY artificial rain gutters (ARGs) |
|
Back to top |
|
|
jackbombay Samba Member
Joined: October 19, 2007 Posts: 2723 Location: Eastern Idaho
|
Posted: Fri Apr 26, 2013 6:57 am Post subject: |
|
|
WLD*WSTY wrote: |
Nice mod, thanks for the writeup! I'll be doing that upgrade soon.
Now, who has the mod to allow the circulation fan to run for a couple of minutes AFTER the burner shuts down? My home furnace does that, moving the residual heat out of the furnace into the house. I've found that the Propex has that heat left over too, and I can manually flip on the fan as soon as the burner shuts down and get warm air for 2-3 minutes. Now to find a way to do that automatically. I figure that should improve efficiency by at least 10%. |
My propex is new, and it does just that, 3 minutes of "after run", maybe a new thermostat would make yours run like this? _________________
Gas struts to pop your top easily!
Pop Top strut kits now available for late Bay window Westies
Samba ad here.
DIY artificial rain gutters (ARGs) |
|
Back to top |
|
|
jackbombay Samba Member
Joined: October 19, 2007 Posts: 2723 Location: Eastern Idaho
|
Posted: Fri Apr 26, 2013 7:06 am Post subject: |
|
|
Results from last night, the 22k ohm resistor lowered the whole temp range about 30*, with the thermostat maxed out, the heater clicked on when it got down to 50* F, normally at the max setting the heater should kick on at 80*.
So, for every 1k ohms of resistance added to 12k, the whole range will drop 3*, a 15k resistor should drop the range to 41*-71*.
I have done some reading around about resistors and you can get virtually any resistance you want by running them in series, so if you was a 15* temp drop you can run a 15k and a 2k ohm in series for a total of 17k ohms. _________________
Gas struts to pop your top easily!
Pop Top strut kits now available for late Bay window Westies
Samba ad here.
DIY artificial rain gutters (ARGs) |
|
Back to top |
|
|
westyventures Samba Member
Joined: December 29, 2004 Posts: 2305 Location: Oregon Outback
|
Posted: Fri Apr 26, 2013 8:31 pm Post subject: |
|
|
WLD*WSTY wrote: |
Nice mod, thanks for the writeup! I'll be doing that upgrade soon.
Now, who has the mod to allow the circulation fan to run for a couple of minutes AFTER the burner shuts down? My home furnace does that, moving the residual heat out of the furnace into the house. I've found that the Propex has that heat left over too, and I can manually flip on the fan as soon as the burner shuts down and get warm air for 2-3 minutes. Now to find a way to do that automatically. I figure that should improve efficiency by at least 10%. |
What vintage is your heater? Only the really old EX1800 series and prior don't after-run. If yours doesn't, then it may have a circuitry issue. |
|
Back to top |
|
|
WLD*WSTY Samba Member
Joined: November 04, 2009 Posts: 438 Location: Arizona
|
Posted: Fri Apr 26, 2013 10:04 pm Post subject: |
|
|
Karl, I've got an older 1600, which works fine but I guess I need to find a schematic of the newer thermostats and retro the circuitry into mine. If you might know where I can find that circuitry online, please let me know. _________________ '82 SyncroWesty, the first ever conversion.'06 Subaru 2.5L |
|
Back to top |
|
|
westyventures Samba Member
Joined: December 29, 2004 Posts: 2305 Location: Oregon Outback
|
Posted: Sat Apr 27, 2013 8:16 am Post subject: |
|
|
WLD*WSTY wrote: |
Karl, I've got an older 1600, which works fine but I guess I need to find a schematic of the newer thermostats and retro the circuitry into mine. If you might know where I can find that circuitry online, please let me know. |
The newer thermostats won't work with your model. I'll ask Propex if there is a way to make it after-run without too much trouble. Usually those older models would only after-run if it detected the heat chamber was too hot, and would come back on briefly. |
|
Back to top |
|
|
westyventures Samba Member
Joined: December 29, 2004 Posts: 2305 Location: Oregon Outback
|
Posted: Sat Apr 27, 2013 8:22 am Post subject: |
|
|
jackbombay wrote: |
Results from last night, the 22k ohm resistor lowered the whole temp range about 30*, with the thermostat maxed out, the heater clicked on when it got down to 50* F, normally at the max setting the heater should kick on at 80*.
So, for every 1k ohms of resistance added to 12k, the whole range will drop 3*, a 15k resistor should drop the range to 41*-71*.
I have done some reading around about resistors and you can get virtually any resistance you want by running them in series, so if you was a 15* temp drop you can run a 15k and a 2k ohm in series for a total of 17k ohms. |
Great work, thanks for the detailed experiment - this should help out tremendously! Maybe we can get Propex to install a slightly higher resistor standard. Seems like a 45-75 range would be better suited to most folks. I've alerted them to this thread. |
|
Back to top |
|
|
jackbombay Samba Member
Joined: October 19, 2007 Posts: 2723 Location: Eastern Idaho
|
Posted: Sat Apr 27, 2013 8:39 am Post subject: |
|
|
westyventures wrote: |
Great work, thanks for the detailed experiment - this should help out tremendously! Maybe we can get Propex to install a slightly higher resistor standard. Seems like a 45-75 range would be better suited to most folks. I've alerted them to this thread. |
You're welcome
I installed a 17k resistor yesterday and I think its just about perfect for me. When the thermometer by my thermostat read 67* I had to have the thermostat knob about 1/8" of rotation (measured at the edge of the knob) from full blast to get the heater to come on. I don't have "lowest setting" info available yet, but once I get home in may we should should still have some nights in the 20's so I should have info on that soon. _________________
Gas struts to pop your top easily!
Pop Top strut kits now available for late Bay window Westies
Samba ad here.
DIY artificial rain gutters (ARGs) |
|
Back to top |
|
|
Jon_slider Samba Member
Joined: April 11, 2007 Posts: 5091 Location: Santa Cruz, Crowdifornia
|
Posted: Sat Apr 27, 2013 9:52 am Post subject: |
|
|
great job!
Im left wondering what the range of the thermostat is, once it is set.
iow, lets say it comes on at 50F, how high does it go before it shuts off.. 60F? That would be a 10 degree swing between off and on..
just curious how big the temperature swing is between thermostat on and off trigger points, for example, if set to shut off at 50, does it actually drop to 40, or less, before it comes on again? _________________ My Soapboxes: Inflation; Handling; Gearing; Decoupling; Swepco |
|
Back to top |
|
|
jackbombay Samba Member
Joined: October 19, 2007 Posts: 2723 Location: Eastern Idaho
|
|
Back to top |
|
|
Witless Joe Samba Member
Joined: May 06, 2005 Posts: 460
|
Posted: Sun Apr 28, 2013 10:27 am Post subject: |
|
|
jackbombay wrote: |
the van |
Is this on the Sprinter, or did you get another Vanagon? |
|
Back to top |
|
|
jackbombay Samba Member
Joined: October 19, 2007 Posts: 2723 Location: Eastern Idaho
|
Posted: Sun Apr 28, 2013 8:15 pm Post subject: |
|
|
Witless Joe wrote: |
jackbombay wrote: |
the van |
Is this on the Sprinter, or did you get another Vanagon? |
El sprinter.
Currently down south enjoying some warm weather, the Detroit coozie was given to me years ago and I always try to get pics with it in unique locations and I send the pics to the guy who gave it to me...
_________________
Gas struts to pop your top easily!
Pop Top strut kits now available for late Bay window Westies
Samba ad here.
DIY artificial rain gutters (ARGs) |
|
Back to top |
|
|
westyventures Samba Member
Joined: December 29, 2004 Posts: 2305 Location: Oregon Outback
|
Posted: Mon Apr 29, 2013 9:30 am Post subject: |
|
|
jackbombay wrote: |
Witless Joe wrote: |
jackbombay wrote: |
the van |
Is this on the Sprinter, or did you get another Vanagon? |
El sprinter.
|
I know that is no Vanagon, but inquiring/interested minds would like to see what you've done with the interior. My 'next' camper is going to be a custom Sprinter also. |
|
Back to top |
|
|
westyventures Samba Member
Joined: December 29, 2004 Posts: 2305 Location: Oregon Outback
|
Posted: Mon Apr 29, 2013 9:36 am Post subject: |
|
|
More from Propex UK:
In the older Compact 1600 the post purge cycle is controlled by a 60 degree n/o thermostat in the heater, but of course under normal running that temperature would not be reached unless the heater was forced to run hot.
If that thermistor was changed for a 50 degree thermostat it may persuade it to come on more readily. |
|
Back to top |
|
|
|