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Topic: Furnace Operation (Read 913 times) previous topic - next topic

Furnace Operation

Merry Christmas everyone,
I have a question concerning my furnace operation.
Can I run both heat pumps and the furnace at the same time?  If so, how do you set the thermostat for both the furnace and heat pump?  It shows you can choose furnace or heat pump in zone 1, but I can't understand how to get them to work at the same time.

Also, to those responsible for the new look to the website.  VERY nice.

Cheers,
Jerry
1999 u270 WTFI 34ft.
Jerry & Nanci
1999 U270 34'WTFI
2011 Malibu
A smart man knows what to say, a wise man knows when to say it.

Re: Furnace Operation

Reply #1 –
Jerry, the short answer is no, you run the furnace,or the heat strips, are you sure you have heat pumps or heat strips, most U270'S have heat strips,unless it was ordered with heat pumps.
The selected media item is not currently available.Bill&Doris 97 U270 36'
University of Parris Island Class of 66
Semper Fi  Build# 5174 MC#17094

Re: Furnace Operation

Reply #2 –
Our U295 has two furnaces, two air conditioners with heat strips, and a five button control unit. Zone 1 is the front furnace and front air conditioner. Zone 2 is the rear furnace and rear air conditioner. My experience has been that we cannot use the heat strips and furnaces at the same time. Also, the two zones must be in the same mode, or one zone must be off for systems to work.

We don't use the heat strips. When storing the coach in cold weather, I leave the rear furnace turned on because it provides heat to the basement.

Experts may know how to coax mixed modes from the controller and heating units.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Furnace Operation

Reply #3 –
Our 1999 U270 has heat pumps as indicated in the Dometic thermostat display, but I can also see that on the documentation that came with the coach that it was ordered as an option. Since the power is off to everything, I can't try it right now but it seems like it would be a shame if you couldn't use both at once... Though that might require ear plugs ;D
Don
Quote from: Bill Willett –
Jerry, the short answer is no, you run the furnace,or the heat strips, are you sure you have heat pumps or heat strips, most U270'S have heat strips,unless it was ordered with heat pumps.
The selected media item is not currently available.
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Furnace Operation

Reply #4 –
Maybe I stated that wrong.  I assumed heat pumps because of the heat stripes.  I wasn't aware you could have heat strips without a heat pump.  On my thermostat you push the button until the mode you want comes up.  You have to go past the heat stripes to get to the furnace.  I couldn't understand having both and not having use of both at the same time.

Jerry
Jerry & Nanci
1999 U270 34'WTFI
2011 Malibu
A smart man knows what to say, a wise man knows when to say it.

Re: Furnace Operation

Reply #5 –
Jerry,

Roof A/C's EITHER have heat strips or are heat pumps. 

Heat strips are just resistance heater coils and can be used in any temperature.

Heat pumps are "reverse cycle" A/C's so the condenser becomes the evaporator. They work well down to about 40 degrees F.

Very different beasts.

Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Furnace Operation

Reply #6 –
Brett,
Thanks for the info.  My only expeience with heat strips are home units.  Heat pumps with heat strips for lower temps.  Thus, I just assumed if it had strips it was a heat pump, also my previous SOB had 2 A/C's and 2 furnaces.
Thanks again for the information,
Jerry
Jerry & Nanci
1999 U270 34'WTFI
2011 Malibu
A smart man knows what to say, a wise man knows when to say it.

Re: Furnace Operation

Reply #7 –
Quote from: Green99 –
...........................................Can I run both heat pumps and the furnace at the same time?  If so, how do you set the thermostat for both the furnace and heat pump?  It shows you can choose furnace or heat pump in zone 1, but I can't understand how to get them to work at the same time...................................................
Jerry,
U270's (1997 thru 2005) came standard with roof top AC's with Heat Strips, not Heat Pumps.  Some U270's may have had Heat Pumps installed as options or the original rooftop AC's may have been replaced.
The dual thermostat controller is set up to intentionally prevent simultaneous running of either (or both) of the rooftop AC's with the furnace.
The standard, single U270 40,000 BTU propane furnace far outweighs the heat output capacity of the two AC heat strips (1200 Watts each) combined.  So It doesn't make design sense to put simultaneous, additional rooftop AC electrical loads on the 8,000 KW generator when they won't contribute much more than additional air movement and background noise.
For us:
If the coach is cold, turn on the furnace to heat the coach up (it occurs rapidly..........within a few minutes).  Then shift over to the heat strips, which with ('98 and after) thermopane windows and day/night shades drawn, will work fine down into the mid 30's F.  Below 32 F, always stay on the furnace to blow heat into the basement.  Heat strips the same but down into the low 40's.
Works fine, lasts a long time and uses electrical capacity simply (and wisely).
Merry Christmas all.
Neal
The selected media item is not currently available.
Neal (& Brenda) Pillsbury
'02 U320 SPEC, 4200, DGFE, Build #5984
'04 Gold Wing
'07 Featherlite 24'
'14 Jeep Grand Cherokee Summit
MC #14494
Exeter, NH & LaBelle FL
Quality makes the Heart Soar long after Price is Forgotten
 

Re: Furnace Operation

Reply #8 –
I can run both at the same time.  I have separate thermostats controlling the furnace and top side units.
Benjie, Ashley, Zoey, Fallon, and Lake
Round Rock, TX
In search of our next monster...