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patriciahawk · 01-21-2019, 07:30 AM

How comfortable can we expect the indoor temp to be if I only use the heat pump? I’m thinking I can get it “so many” degrees warmer than the outside temp (to a certain point).

We live in IL and our 27 GT FBT comes in March. We want to learn all we can while it’s on our property. We will have a 30amp hookup.

Mollysdad · 01-21-2019, 07:41 AM

The heat pump works great...as long as the outside temperature is above about 33.
Below that it's not so good.
Mine has the CCC-2 thermostat, where the gas furnace comes on below a certain temperature.
So if I'm playing for electricity, I use the heat pump first.
I'd recommend a small fan to circulate the air, since the warm air will remain near the ceiling.
That's how I first knew the furnace would come on, I walked into the living area and my feet were toasty!

patriciahawk · 01-21-2019, 07:48 AM

Quote:

Originally Posted by Mollysdad

The heat pump works great...as long as the outside temperature is above about 33.
Below that it's not so good.
Mine has the CCC-2 thermostat, where the gas furnace comes on below a certain temperature.
So if I'm playing for electricity, I use the heat pump first.
I'd recommend a small fan to circulate the air, since the warm air will remain near the ceiling.
That's how I first knew the furnace would come on, I walked into the living area and my feet were toasty!

Thank you. I remember reading that somewhere, but I couldn’t find it to refer back to.

dznf0g · 01-21-2019, 08:34 AM

Ditto what mollysdad said. I also run an electric space heater....not to augment the heat pump (it is fully capable down to mid 30s outside), but just to save some wear and tear on the heat pump/a/c unit.

I modified the furnace blower to run at a low rpm, even though furnace is not called for, in order to keep air circulated evenly throughout the trailer.

dznf0g · 01-21-2019, 08:48 AM

http://www.airforums.com/forums/f427...ase-74624.html

Here is a thread to the reference blower modification.

brick1 · 01-21-2019, 08:56 AM

We have used the heat pump in temps as low as 35 F, and it kept the Airstream more than warm enough.
brick

dznf0g · 01-21-2019, 09:16 AM

My sense is that a lot of people get impatient with the heat pump. When first turning it on, it doesn't put out instant heat, like an electric space heater. It takes a good 10 minutes for really warm air to be produced. Subsequent cycles seem to be much faster. I think some people turn it on and say, "that's cold air, this thing sucks." Then they go to the propane furnace.

patriciahawk · 01-21-2019, 12:10 PM

It’s 8’ here now so it sounds like using an electric space heater would help make it comfortable to hangout in while familiarizing ourselves with the AS functions, or make sure we have propane. I’m not sure how much we can do with it winterized anyway, but we’re so anxious to test out what we can.

Overstreet · 01-25-2019, 09:07 AM

Quote:

Originally Posted by dznf0g

My sense is that a lot of people get impatient with the heat pump. When first turning it on, it doesn't put out instant heat, like an electric space heater. It takes a good 10 minutes for really warm air to be produced. Subsequent cycles seem to be much faster. I think some people turn it on and say, "that's cold air, this thing sucks." Then they go to the propane furnace.

Heat pumps heat using a small temperature differential. Thus they have to run longer to raise the temp of the trailer. It also will "feel" like cool air because of the evaporation of moisture on the skin in the "wind" of the blower. Like dznfog inferred have patience.....and give it plenty of run time. You could of course turn both on heat pump, and furnace to bring the cold trailer up to temp then turn furnace off. To make the trailer warm it has to warm the air AND all that solid stuff like cabinets, pillows, cushions, counter tops, interior skin, etc.

For information the Alde system, a hydronic system, needs some lead time and run time to keep the trailer at temp too.

Overstreet · 01-25-2019, 09:12 AM

The other way to heat up a cold trailer for the heat pump to take over is to bake cookies. Much tastier than running the furnace.

SewStream · 01-26-2019, 07:55 AM

Hi @patriciahawk - I can relate to your excitement about the delivery of your new Globetrotter! Do you have one or two AC units? On a 30 amp service/hook up, you can only run one unit.

For what it’s worth...this is our real-life experience using the furnace and heat pump in our 2019 27FB Globetrotter. We are currently in Florida and travel full-time in the Globetrotter. Right now, it’s *cold* at 47 degrees outside temp. We have 50 amp shore power, so we could run both heat pumps. However, it is HUMID in Florida and we have not had a good experience running the heat pumps as it draws in the moisture from the outside air. The relative humidity in the GT has been as high as 95% when using the heat pumps! The inside of the GT was dripping from all the moisture being pulled in by the heat pump. So, with high humidity, we use the furnace set to 60-65 degrees. We are comfortable with little moisture buildup inside the Airstream.

We use the heat pumps with success when the outside humidity is lower and the temperatures are in the 35-50 degree range. Your head will be toasty, your feet, not-so-much. Another caveat, when the outside temperature is below 42 degrees, your heat pump is going to start a defrost cycle to avoid frosting over. The fan shuts off, and the refrigerant reverses itself to defrost the system. That can be alarming the first time you hear this! Just know this is how it works.

The heat pump is going to cycle on and off when the temperatures are between 42 to 30 degrees. Once the outside temperature reaches below 30 degrees, your system is going to automatically switch over to the furnace. You must make sure your propane tank(s) are OPEN even if you are using the heat pump, so that your furnace can start!

dznf0g · 01-26-2019, 08:01 AM

Heat pumps do not draw in outside air nor moisture. You are experiencing condensation from showers, cooking, and respiration. Many threads on this. If there is an inside/outside air exchange, you have a sealing problem with a/c (heat pump) unit.

Al and Missy · 01-26-2019, 08:25 AM

What Rich said....

SewStream · 01-26-2019, 08:34 AM

@dznf0g - we beg to differ. This is our reality! No showers going on, no cooking, there was respiration as we are not 6’ under. It was nighttime. Thanks for your interesting comment about a possible sealing problem with two new Dometic units on a less-than-eight-month-old Globetrotter...hmmm...we’re going to be at the dealer next Wednesday. Will definitely talk to them about this issue.

In the meantime, our REAL life experience is that our units were actually blowing moisture out of the ducted vents creating dripping condensation of the ceiling of the Airstream! Not the windows, not the walls - the ceiling. We get NO moisture when we run the furnace. None! This is when cooking, showering, and breathing while using the furnace. Go figure...just happens in high humidity running the heat pumps. Just keeping it real...

dznf0g · 01-26-2019, 08:41 AM

Quote:

Originally Posted by SewStream

@dznf0g - we beg to differ. This is our reality! No showers going on, no cooking, there was respiration as we are not 6’ under. It was nighttime. Thanks for your interesting comment about a possible sealing problem with two new Dometic units on a less-than-eight-month-old Globetrotter...hmmm...we’re going to be at the dealer next Wednesday. Will definitely talk to them about this issue.

In the meantime, our REAL life experience is that our units were actually blowing moisture out of the ducted vents creating dripping condensation of the ceiling of the Airstream! Not the windows, not the walls - the ceiling. We get NO moisture when we run the furnace. None! This is when cooking, showering, and breathing while using the furnace. Go figure...just happens in high humidity running the heat pumps. Just keeping it real...

Ah, but you have cold ducts when first starting up the heat pump. That equals condensation of the moisture in the air INSIDE the trailer. Depending how well these ducts are insulated, that should subside with some interior temp equalization. However , I suspect, in cold weather, the ducts never really warm up. I think they are pretty poorly insulated. This is not a function of the heat pump. If your furnace were plumbed to the overhead ducts, same thing would occur. I would recommend you get a dehumidifier for use in temps below 50* or so. Your problem will go away. Many threads on this as well. A human expels about a quart of water a day. It condenses where cold surfaces exist.
Edit: I assume you have the alde heat system and not a furnace....so for this experiment, you would just turn on the fan (no heat pump compressor) in cold weather after alde warms the trailer. I'd bet, under identical weather/occupancy parameters moisture will condense in your ducts.

ROBERT CROSS · 01-26-2019, 09:12 AM

Since we first started Streaming in '88 we have found the most reliable way to stay warm in an AS....
Better safe than sorry.😂

Bob
🇺🇸

dznf0g · 01-26-2019, 09:18 AM

Quote:

Originally Posted by ROBERT CROSS

Since we first started Streaming in '88 we have found the most reliable way to stay warm in an AS....
Better safe than sorry.[emoji23]

Bob
[emoji631]

...butt flap, or no butt flap?

SewStream · 01-26-2019, 09:28 AM

If your assertion is correct that moisture was already present in the air, then we should’ve had condensation appearing on the windows and walls because they were quite cold. We have never had a moisture problem in the AS from breathing, cooking, or showering. We find the fans and range hood adequate for removing this moisture. However, we have only camped in temperatures down to 32 degrees.

The humidity in the GT jumped from 50% to over 95% in less than ten minutes when the heat pump was turn on. This was measured with our digital hygrometer. The relative outside humidity was high. My husband contacted Airstream technical support as this was quite alarming!

He got this response directly from the Airstream technical support team in Jackson Center about our 2019 Dometic units:

“The AC unit in normal conditions pulls moisture in and then pulls in heat from your trailer. In the heat pump mode it works in reverse. It is trying to pull in any heat from outside. But unfortunately, it will pull in moisture first. I recommend using your furnace as it has dry hot air.”

SewStream · 01-26-2019, 09:35 AM

@patriciahawk - I am sorry if this hijacks your post. I am trying to give you our personal experience as we are in the same Airstream you have on order for delivery in March. We have been in our 2019 GT full-time (24/7) for months now. We love it! I hope you enjoy your Globetrotter as much as we do!

dznf0g · 01-26-2019, 09:37 AM

Quote:

Originally Posted by SewStream

If your assertion is correct that moisture was already present in the air, then we should’ve had condensation appearing on the windows and walls because they were quite cold. We have never had a moisture problem in the AS from breathing, cooking, or showering. We find the fans and range hood adequate for removing this moisture. However, we have only camped in temperatures down to 32 degrees.

The humidity in the GT jumped from 50% to over 95% in less than ten minutes when the heat pump was turn on. This was measured with our digital hygrometer. The relative outside humidity was high. My husband contacted Airstream technical support as this was quite alarming!

He got this response directly from the Airstream technical support team in Jackson Center about our 2019 Dometic units:

“The AC unit in normal conditions pulls moisture in and then pulls in heat from your trailer. In the heat pump mode it works in reverse. It is trying to pull in any heat from outside. But unfortunately, it will pull in moisture first. I recommend using your furnace as it has dry hot air.”

I believe they are quite incorrect. The evaporator side of the system is completely separated from the condenser side of the system. Unless there is a defect in sealing, there is no cross pollination, or exchange of air from inside to outside. The refrigerant system simply reverses for an a/c unit to perform heating functions. That's all, period.

That person was blowing you off with incorrect information.