Basement Heat issue

RanchoVectra · 12-02-2007, 05:04 AM

This may be a little long, appreciate your patience.

Outside temps last night in S Cal got down into low 30's. Had the suburban furnace on as well as the elec heat mode of the True Air/ RVP unit. About 2 am heard a loud bang in the coach, quick inspection didn't show anything obvious nor any smells. Figured it had something to do with basement heat, but went back to sleep as suburban was still running. This morning True Air temp was 4 degrees below set-point and the unit was not operating. Changing the set point made no difference, nor did trying to put the fans "on". Checked all breakers, did visual outside the coach, no apparent problems. Checked the Winnie owners manual and found an explanation that if the temps drop to 5 degrees the unit will shut off and should switch to LP heat. Did that, and furnace came back on providing heat to the front of the coach from the floor registers. So, my questions:

1 Does the True Air / RVP unit include a furnace as well as the heat pump ?
2. any idea on the source of the bang - it was definitely internal to the coach, so I initially suspected a fan let go, but they are running now with the unit on LP (unless, of course, there are different fans for the heat pump side and the furnace side)
3. I didn't see any mechanical / HVAC diagrams in the Winnie lists that give actual locations of the units, fans and ductwork and RVP's website does not have them either. If anyone who can point me in that direction it will be appreciated.

Any other thoughts or ideas are appreciated.

RanchoVectra · 12-02-2007, 05:04 AM

This may be a little long, appreciate your patience.

Outside temps last night in S Cal got down into low 30's. Had the suburban furnace on as well as the elec heat mode of the True Air/ RVP unit. About 2 am heard a loud bang in the coach, quick inspection didn't show anything obvious nor any smells. Figured it had something to do with basement heat, but went back to sleep as suburban was still running. This morning True Air temp was 4 degrees below set-point and the unit was not operating. Changing the set point made no difference, nor did trying to put the fans "on". Checked all breakers, did visual outside the coach, no apparent problems. Checked the Winnie owners manual and found an explanation that if the temps drop to 5 degrees the unit will shut off and should switch to LP heat. Did that, and furnace came back on providing heat to the front of the coach from the floor registers. So, my questions:

1 Does the True Air / RVP unit include a furnace as well as the heat pump ?
2. any idea on the source of the bang - it was definitely internal to the coach, so I initially suspected a fan let go, but they are running now with the unit on LP (unless, of course, there are different fans for the heat pump side and the furnace side)
3. I didn't see any mechanical / HVAC diagrams in the Winnie lists that give actual locations of the units, fans and ductwork and RVP's website does not have them either. If anyone who can point me in that direction it will be appreciated.

Any other thoughts or ideas are appreciated.

rvten · 12-02-2007, 06:27 AM

Heat pump is only good to about 40 deg. If HP is on and it drops lower than 40 gas furnace should kick in. The gas furnace is seperate from the HP. Could be the HP froze up or just a hard shut down.

Pusherman · 12-02-2007, 06:47 AM

Also -- when only the heat pump is running, no heat gets to the basement area. It uses only the a/c ducts to distribute air.

Furnace will heat the basement area. So if it's going to be below 40d F, it's a good idea to shut the heat pump off and only use the furnace if it's going to get below freezing, so as to keep the basement area heated.

RanchoVectra · 12-02-2007, 06:53 AM

Thanks, Tom, I think you have it right. Just switched back to Elec, and after the usual slight delay the unit came back on, and when I dropped the thermostat it went off normally. Guess when the overnight temps are expected to be below 40 we'll switch to LP to run the furnace.

rgrstndgby · 12-02-2007, 07:34 AM

[quote]Pusherman
"Winnebago Coach Forum Member"

Posted December 02, 2007 11:47 AM Hide Post
Also -- when only the heat pump is running, no heat gets to the basement area. It uses only the a/c ducts to distribute air.

Furnace will heat the basement area. So if it's going to be below 40d F, it's a good idea to shut the heat pump off and only use the furnace if it's going to get below freezing, so as to keep the basement area heated.
...................................

Pusherman makes a good point, one that easy to overlook, especially by us "Desert Rats...rgr...

JB Texas · 12-02-2007, 08:33 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RanchoVectra:
Thanks, Tom, I think you have it right. Just switched back to Elec, and after the usual slight delay the unit came back on, and when I dropped the thermostat it went off normally. Guess when the overnight temps are expected to be below 40 we'll switch to LP to run the furnace. </div></BLOCKQUOTE>

The system will do it automatically. If there is more than a 3 degree spread in the set point and ambient temp the gas furnace will come on to assist the heat pump. If the heat pump is unable to bring the temp up to the set point it will eventually shut down. Also, if the outside air temp is too low, the heat pump shuts down, leaving the gas furnace to provide heat. This happens when Electric Heat is selected on the thermostat.

RRT2 · 12-02-2007, 08:38 AM

The gas furnace will automatically kick in when electric HP won't.....providing, of course, someone has turned the LP gas ON!

Been there, done that! Not fun to wake up with external temps in 20's...internal temp 50 and heat won't come on!!

LOL...but we survived a Dallas freeze anyway!

Rose

Bill Gotthelf · 12-02-2007, 10:25 AM

The AC blower is completely seperate from the LP gas heater blowers. There is no electric furnace or heating elements in your electric AC.

j griff · 12-02-2007, 07:37 PM

"About 2 am heard a loud bang in the coach, quick inspection didn't show anything obvious nor any smells."

Phil,
We often get quite a loud bang as the heating ducts become warm - guess it is just a natural expansion of the metal someplace along the duct. Sure did startle us the first time it happened.

RanchoVectra · 12-03-2007, 03:52 AM

Thanks, guys, I think you all must be correct about the furnace coming on automatically as the coach was within a couple degrees of the setpoint - I just must not have noticed air coming from the floor registers.

In the interest of full disclosure.... I think the loud bang was the shampoo caddy on the wall of the shower falling off during the night since we found it on the floor of the shower later that morning. Funny how an unrelated incident will make you (me!) jump to conclusions!

DancinCampers · 12-03-2007, 02:23 PM

There are 2 different ways the gas furnace turns on when the thermostat is set for electric heat.

The following is one way, which is when the heat pump can't keep up with the set temp:

Heat Pump Example To Bring On Gas Furnace As Backup Heat

Setpoint Indoor Temp. Operation
70 70+ No functions occur
\\\ 69 Heat Pump turns on (Primary heat source)
71 Heat Pump turns off (Thermostat satisfied)
69 Heat Pump turns on
65 Gas Furnace turns on, Heat Pump turns off (Heat Pump not able to satisfy Thermostat) (First strike for backup heat counter)
71 Gas Furnace turns off (Thermostat satisfied)
69 Heat Pump turns on
65 Gas Furnace turns on, Heat Pump turns off (Heat Pump is again unable to satisfy Thermostat), (Backup heat counter reaches 3rd strike and Heat Pump is locked out for 2 hours), backup heat counter is reset if Heat
Pump is running for more than 20 minutes and does not call for backup heat
71 Gas Furnace turns off (Thermostat satisfied)
69 Gas Furnace turns on (Becomes Primary heat source)
71 Gas Furnace turns off (Thermostat Satisfied)
\\\ After 2 hour lockout
69 Heat Pump turns on (Resumes as Primary heat source)
65 Gas Furnace turns on, Heat Pump turns off (Becomes Primary heat source) (Heat Pump is locked out for another 2 hours)
71 Gas Furnace turns off (Thermostat Satisfied)
\\\ After 2 hour lockout
69 Heat Pump turns on (Resumes as Primary heat source)
71 Heat Pump turns off (Thermostat Satisfied) (Backup heat counter is
reset any time Heat Pump satisfies thermostat setpoint and does not need Gas Furnace)
The word "DIFF" will display on LCD when backup heat is operating and the heat pump is locked out. There is a 30 second delay between
Stage 1 and Stage 2. There is also a 3 minute anti-short cycle delay time for cooling.

The second way is when the outdoor freeze sensor opens & shuts down the heat pump. Under this condition, the gas furnace will operate. BUT, according to the manual, in this case it will come on when the indoor temp reaches 45 deg F & turn off when the indoor temp reaches 60 deg F. At this time the thermostat should be changed over to gas.

I did have this happen to me once. Took me awhile to figure out. Once you change the tstat to gas the thermostat will operate as you have set it.

Hope I haven't confused anyone.