heater does not get hot

my dad bought a Camry last week. its interesting in that i looked over his options and other than lojack, his options were nothing more than what i had... and although his car shipped from Georgetown, KY(shipping $540.... obviously the amount of miles the car actually travels has no bearing on this charge) the difference in the price of the cars was only $200 when you take out the different options.

his total price was $21K+ after the lo-jack and the firstaid/mat/emergency kit were added. the bumper to bumper warantee is the same but my powertrain?? warantee is better (his was 5 years, 50K)

to make it fair, his car is more powerful and he does get power seats standard, but the stereo appears to be exactly like mine complete with steering wheel controls and everything. his is a 2005 and if you compare 2005 Prius prices then the price difference will be more by 700 making the difference about $900.

the car's interior seems much larger in the front seat but just about the same in the back. the car rides smoother somewhat (like a typical big car) but it takes MUCH longer to warm up than my Prius does. but i have not had an issue with my heater (pretty mild here though) in fact, i frequently toggle the heat on and off because it works too well on days when its only around 45-50º. and the camry will heat up in just a few miles. the car seems to be insulated better. road noise is less i think.

but all this comes at a huge price. EPA says 24/34 mpg. my dad is getting ready to go on a cross country driving trip hitting 18 states and will be tracking mileage. after his first tank of gas, he is getting 27 mpg. (realize we have ethanol and winter formula gas and i believe most of his driving has been local so far)
so its a good 20 mpg drop in economy.

 

It's around -25 C right now. When I left the condo this morning, I exercised the A/C. With the HVAC fan at lowest setting, when you press the A/C button on the MFD, you can hear the compressor engage and within 5 secs hear the distinctive noise of refrigerant hissing through the expansion orifice.

Parked at the mall for around 3 hours to do Xmas shopping, Yikes that north wind was brutal! In the car, tried to cycle the A/C again: the compressor did not engage, no matter what permutation of vents or temps I selected on the screen. Even though the MFD indicated that A/C mode was on.

Back at the condo, had a nice long lunch and went back down to the heated underground parking. Using the same permutation of vents and/or temp, the compressor engaged.

I checked the shop manuals for my 2000 GMC Sierra again: the low-temp cutout for the compressor doesn't do anything to the dash A/C switch, so the switch can claim A/C is engaged while the compressor is cutout.

Most R-134a systems also have high pressure and low pressure sensors to protect the compressor. This will cause the compressor to cutout if abnormally high or low pressures are encountered.

With an industrial York chiller and Industrial Ethernet communication, you can recall and trend compressor cycling based on high pressure, low pressure, or low ambient temp cutouts.

Even with a 10kw 3-phase electric blanket, the compressor has to stop every 5 minutes and wait for the crankcase temp to come back up.

 

did you put your clamp on inductive ammeter on the line to the compressor as it has both a high and low speed?

 

<div class='quotetop'>QUOTE(Frank Hudon\";p=\"58449)</div>

If you're asking about the compressor on my Prius, I just used my ear. With the fan at the lowest setting, it's very easy to hear the distinctive whine of refrigerant out the expansion orifice. If you're refereing to the industrial chillers I mentioned ...

The York chiller I'm familiar with has inductive pickups on both the low and high speed side to track power consumption. The data is packaged to a built-in web server and sent via Industrial Ethernet to the plant control network. You can also configure and have built a chiller with ControlNet or DeviceNet, whichever you prefer.

Using the Emerson PlantWeb DeltaV control network, you can download support software from York to have a plug-in on your Plant Utilities page. For example: KW instant, KW hour total, KW shift total (Also day, week, month, year, resettible counters, etc etc) high pressure trip, low pressure trip, thermistor from motor, thermistor from compressor, thermistor from crank heater, alarms, etc etc.

The MCC is a Rockwell / Allen Bradley IntelliCenter with DeviceNet communications and an approved interface to PlantWeb. The chiller, fed off the MCC, also is monitored through the AB interface. You can monitor for single phasing, time to trip, time to overload, stall, jam, KW instant and summary, phase imbalance, etc etc.

I started out with old fashioned MCC and 4-20mA control. There's a good reason it belongs in a museum. I much prefer the increased monitoring and vastly superior equipment/personnel protection offered by modern industrial control and smart equipment interfaces.

Especially for equipment that can be easily damaged if not tracked, like chillers and VSD's, the ability to monitor and alarm on so many parameters is truly a God send. The first time you save a 200hp electric motor from burning out due to stall/jam, you've paid for most of the MCC and control software.

Most MCC have the heater coils sized too large to prevent nuisance tripping. If sized that way, a stall/jam usually won't trip until the motor is good and cooked. If you really want to monitor a motor, you can also use PTC thermistor input from the motor.

 

8) Push the auto A/C button on the steering wheel. Then turn your display to the temperature control screen. You will see a yellow line showing that the A/C is on. Touch the A/C button on the display and it will now turn it off. You will now be able to leave it on A/C auto without the compressor coming on.

You will be able to adjust the fan speed in this mode by either increasing and/or decreasing your temperature from your steering wheel controls.

I had no problem last winter here in Omaha, NE, staying very warm in my 04 Prius. I normally just leave the inside temp at between 68 and 70 degrees.

Ben

 

Hmm... I don't find the Prius temperature controls to be lacking at all. The autoclimate control works great, I only change my temperature settings maybe a couple of times a month, and the occasional use of front/rear defrost.

One nice thing about the touch screen climate controls - it keeps passengers from messing with your preferred settings.

Dave

 

Jayman said
"but during the winter, I guess it acts a a dehumidifier."

no kidding here on the wet coast we'd die without the dehumidifing effect of A/C. You'd never see out your windows and you'd melt in the seat when the temp comes up. Nothing like 99-100% humidity for months on end. You know the old saying about us westcoasters, we don't tan we rust. just checked current humidity 94% temp 10.5C oh that's plus

 

I use my temp. control just like revumeum

 

<div class='quotetop'>QUOTE(jaguaraja\";p=\"58356)</div>

How do you think the moisture is removed from the air? In most systems (including the Prius), the air is cooled below the dewpoint temperature. Condensation forms on the coils and is drained from the system. The cold air is then reheated back to it's required discharge temperature. However, if there is insufficient heat available, the air will be colder than desirable. It is true that "Auto A/C" does not necessarily mean the air conditioning compressor is running, but it will be if dehumidification is required.

 

That's why I could never live in a cool DAMP climate like Vancouver. It would kill me. I don't mind cold dry climates, and really like hot dry climates. I could easily live in Mesquite, NV, love that place. I visited a friend there in August when it was 116 in the shade. Dry as a bone and I felt very comfy inside with the A/C set at 84.

Bring it on!

Hot ambient has much greater dewpoint than cold ambient. As an example, if you're at +35 C, the humidity can easily be 100% or saturated. No thanks, that sux.

At -35 C, the dewpoint is such that there is very little humidity in the air. Any "excess" humidity turns into ice crystals. You're lucky if you see 20% humidity on a clear, cold day.

You get frost in a car due to single pane glass and the extreme temp difference, say -35 C outside and +10 inside. Much like a home, you need tri-pane windows to minimize frost on the glass. You really need that blast of hot air on your car windows to keep the glass clear.

Much like if you have a basement in a cold climate. Once it dips below -5 C for awhile, you can unplug your dehumidifier and leave it that way the entire winter. If you open a basement window at -35 C, the humidity in the house will go LOWER.

There are some situations in IT and industrial process control where you need cooling, even at -40 C ambient. In those situations, you have to take extra care with the compressor to make sure the crankcase is kept heated, otherwise you'll ruin the compressor.

Since automotive A/C compressors don't have crankcase heaters, they use thermistors to disable the clutch below a certain threshold.

 

<div class='quotetop'>QUOTE(Frank Hudon\";p=\"58550)</div>

Actually, Tideland Prius said that, not me.

 

sorrry Jayman

 

<div class='quotetop'>QUOTE(Tideland Prius\";p=\"58605)</div>

It's probably a factory-default "deadband" before it can switch from cool to heat, or v-v.

As an example, I have a Bryant Evolution 90i Plus gas furnace at my hobby farm, with a Bryant 2-speed Puron central A/C. The entire system is networked and controlled by Bryant's Evolution system, which suspiciously looks like DeviceNet, even down to the color coding of the 4-wire interface.

The Evolution uses an ODT (Out Door Temperature) sensor to fine-tune the PID for the variable-speed furnace fan and variable-burn gas burner. This is also used to determine how long the HRV can run in colder temps before a defrost cycle.

The factory-default deadband is 4 degrees F, though it can be adjusted to 6 or 8 F. This is to prevent unnecessary cycling of the system, which can increase wear and increase energy use. You can also set the cycles/hour (Default is 4/hour max, can select 6,8, or 12 per hour max).

That's why we can have automobiles and home HVAC so efficient: intelligent system control over operation. Though sometimes, such as when driving along, it may not provide what you expect.

Note: there is also a sensor in the dash, left side bottom corner by the windshield, that is used to fine-tune the Auto HVAC operation.

 

My heater barely works in 0 F weather

It has gotten down to 0 F in St Paul, MN over the past few days. My Prius never gets hot. I had a 30 minute drive last night, and the car never got the cabin warm. When I feel the air coming out of the vents, I would call it slightly warm. I've tried the auto AC, and also tried every manual configuration (manually turning off AC and jacking the temp up to MAX Heat).

I wouldn't call the car cold, but it definitely is not comfortably warm.

In comparison, I have a Nissan Maxima and a Toyota Corolla. Both of these cars get HOT in about 5 minutes of driving in 0 F weather. By the 10 minute point, the heater is turned to low and the temp control is moved towards the blue.

Is there something wrong with my car? I only have 800 miles on the car ... will it improve? Do you guys in Canada experience this problem in 'not-so cold' weather ? (only folks in MN, ND and Canada would call this 'not so cold' weather)

 

On my drive to St. Paul, MN this morning, the Multi-Display showed a nasty -6 F. And I was comfortably warm inside my Prius.

I'm not sure what you actually mean by "hot", but some part of the puzzle is not right.

 

To be more specific. If I have the auto temp set at 70F. After my 25 minute drive last night, I'm fairly confident the cabin never got to 70 F.

 

Re: My heater barely works in 0 F weather

I concur. I find the heat in the Prius to be pretty anemic under extreme cold (say, single digits or under) conditions.

In any other car I owned I would generally take my coat off before entering the car, tough out the first five minutes or so, then would be comfortable. I do this only because I'm not particularly cold-blooded, and I prefer the mild discomfort of a few minutes of cold, to wearing bulky winter clothing in a confined space. I'm reconsidering this habit with the Prius under very cold conditions.

I wonder if this is why they went to the expense of installing a supplemental/auxiliary electric heater?

 

Hmm... As usual with many topics, there is a wide disparity among posters as to the adequacy of [insert automotive function] that is only expressed in subjective terms. In this case it is the heater. In this thread alone, some people love the heater, others need to be convinced.

I wonder, though, if there is another explanation. Those in milder climates might exult in the immediacy of the heat--such as it is--provided by the electric heater. If it is 38 degrees out, it doesn't take much to feel comfortable.

However, for those in the extreme climates, the electric heater's baby breath puff of tepid air will dissipate before it even exits the vents. When you are sitting in a car when it is -10 degrees, afraid to touch anything because it might snap, you need some serious BTU's to warm the cabin up. And for that purpose, you may be ill served by the tiny Prius engine. So you grumble.

Well, it's a theory...