Live in a townhouse condo (middle unit)in Ohio. Will be gone for the
duration of the coming winter. Plan to shut off the water and drain the
water from the pipes. Have no plants in home

How low can I set the thermostat on the heat pump furnace? When I go away
for the weekend in the past, I would set it at about 60. Now since it is
for an extended time, and with the price of fuel up, I would like to set it
lower. I am inclined to set it at 50.

What do you guys think?



--
Have a great day, except you spammers
To email, remove the obvious

.......

"Les" wrote in message

How low can I set the thermostat on the heat pump furnace? When I go away
for the weekend in the past, I would set it at about 60. Now since it is
for an extended time, and with the price of fuel up, I would like to set
it
lower. I am inclined to set it at 50.

What do you guys think?


Set it as low as you can go. I have a building that is set at 40 (hard to
find T'stats that go that low) and never had a freeze up of water lines in
it.

Hi Les, hope you are having a nice day

On 14-Oct-04 At About 12:46:23, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter

L 0001e70 From: "Les"

L Live in a townhouse condo (middle unit)in Ohio. Will be gone for the
L duration of the coming winter. Plan to shut off the water and drain
L the water from the pipes. Have no plants in home

L How low can I set the thermostat on the heat pump furnace? When I go
L away for the weekend in the past, I would set it at about 60. Now
L since it is for an extended time, and with the price of fuel up, I
L would like to set it lower. I am inclined to set it at 50.

A heat pump thermostat should never be set lower than 60 degrees when in heat
mode. any lower and you risk compressor damage.


-= HvacTech2 =-


... I'm always late. My ancestors arrived on the Juneflower.

___ TagDude 0.92á+[DM]
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"HvacTech2" wrote in message
...


Hi Les, hope you are having a nice day

On 14-Oct-04 At About 12:46:23, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter

L 0001e70 From: "Les"

L Live in a townhouse condo (middle unit)in Ohio. Will be gone for the
L duration of the coming winter. Plan to shut off the water and drain
L the water from the pipes. Have no plants in home

L How low can I set the thermostat on the heat pump furnace? When I go
L away for the weekend in the past, I would set it at about 60. Now
L since it is for an extended time, and with the price of fuel up, I
L would like to set it lower. I am inclined to set it at 50.

A heat pump thermostat should never be set lower than 60 degrees when in
heat
mode. any lower and you risk compressor damage.


Turn it clear off ???

--

SVL

HvacTech2;

Could you explain the rational for not setting it lower than 60.
I have a ground source HP with incoming water temp at 50 degrees. If I =
set thermostat at 55 in heat mode, I don't see why there would be any =
damage.
Likewise if set at 45 degrees. Furnace would just run long enough to =
arrive at set temp and then stop until next call for heating.
I'm not an expert. Just trying to learn. Also I set mine at 50 degrees =
when I go on long winter vacation,
Thanks

"HvacTech2" wrote in message =
...
=20
=20
Hi Les, hope you are having a nice day
=20
On 14-Oct-04 At About 12:46:23, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter
(snip)
(snip)
(snip)
=20
A heat pump thermostat should never be set lower than 60 degrees when =
in heat
mode. any lower and you risk compressor damage.
=20
=20
-=3D HvacTech2 =3D-
=20
=20
.. I'm always late. My ancestors arrived on the Juneflower. =
=20
=20
___ TagDude 0.92=E1+[DM]
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Hi Treetops, hope you are having a nice day

On 15-Oct-04 At About 00:52:43, Treetops wrote to All
Subject: Tempiture Setting for Furnace in WInter

T From: "Treetops"

T HvacTech2;

T Could you explain the rational for not setting it lower than 60. I
T have a ground source HP with incoming water temp at 50 degrees. If I
T = set thermostat at 55 in heat mode, I don't see why there would be
T any = damage. Likewise if set at 45 degrees. Furnace would just run
T long enough to = arrive at set temp and then stop until next call
T for heating. I'm not an expert. Just trying to learn. Also I set
T mine at 50 degrees = when I go on long winter vacation, Thanks

it is due to the high pressure side of the unit. if you have an air to air a/c
unit it is the same thing. you cannot use it when the outdoor temp is lower
than 60 degrees. if you do yiou risk slugging the compressor with liquid
refrigerant.

-= HvacTech2 =-


... 3 dreaded words: " hard disk failure."

___ TagDude 0.92á+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
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Ran my HP down to 20 degrees all last winter before gas furnace kicked
in with no ill effects. Explain more in detail why you can not set it
below 60 when leaving home. First year with HP and just trying to
figure out best way to use it. Thanks

On Thu, 15 Oct 2004 17:14:33 , "HvacTech2"
wrote:



Hi Treetops, hope you are having a nice day

On 15-Oct-04 At About 00:52:43, Treetops wrote to All
Subject: Tempiture Setting for Furnace in WInter

T From: "Treetops"

T HvacTech2;

T Could you explain the rational for not setting it lower than 60. I
T have a ground source HP with incoming water temp at 50 degrees. If I
T = set thermostat at 55 in heat mode, I don't see why there would be
T any = damage. Likewise if set at 45 degrees. Furnace would just run
T long enough to = arrive at set temp and then stop until next call
T for heating. I'm not an expert. Just trying to learn. Also I set
T mine at 50 degrees = when I go on long winter vacation, Thanks

it is due to the high pressure side of the unit. if you have an air to air a/c
unit it is the same thing. you cannot use it when the outdoor temp is lower
than 60 degrees. if you do yiou risk slugging the compressor with liquid
refrigerant.

-= HvacTech2 =-


.. 3 dreaded words: " hard disk failure."

___ TagDude 0.92á+[DM]
+++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++
spam protection measure, Please remove the 33 to send e-mail

Thanks for reply.
I think I understand the issue in cooling mode; the cooler air (less =
than 60 degrees) in the house will not transfer enough heat to the low =
side and so the return to compressor could be liquid instead of vapor. =
And compressor doesn't like liquid input.
In heat mode, if air at condenser is 60 degrees, the high side input =
vapor may not become fully liquid. However I don't see how this is a =
problem as the evaporator changes the low side refrigerant to a vapor =
anyway. So compressor still sees low side vapor.
Now I am a way out of my depth!! Maybe you could explain the issue, in =
heat mode, in a little more depth?
Just surprised at the no-no of running less than 60 degrees as I have =
not seen this as a caution in the operating instructions and have done =
it many times over 8 years without problem.
Also does this limitation differ from unit to unit?
Thanks again!

"HvacTech2" wrote in message =
...
=20
=20
Hi Treetops, hope you are having a nice day
=20
On 15-Oct-04 At About 00:52:43, Treetops wrote to All
Subject: Tempiture Setting for Furnace in WInter
=20
T From: "Treetops"
=20
T HvacTech2;
=20
T Could you explain the rational for not setting it lower than 60. I
T have a ground source HP with incoming water temp at 50 degrees. If =
I
T =3D set thermostat at 55 in heat mode, I don't see why there would =
be
T any =3D damage. Likewise if set at 45 degrees. Furnace would just =
run
T long enough to =3D arrive at set temp and then stop until next =
call
T for heating. I'm not an expert. Just trying to learn. Also I set
T mine at 50 degrees =3D when I go on long winter vacation, Thanks
=20
it is due to the high pressure side of the unit. if you have an air to =
air a/c
unit it is the same thing. you cannot use it when the outdoor temp is =
lower
than 60 degrees. if you do yiou risk slugging the compressor with =
liquid
refrigerant.
=20
-=3D HvacTech2 =3D-
=20
=20
.. 3 dreaded words: " hard disk failure." =
=20
=20
___ TagDude 0.92=E1+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
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The lowest I am able to reduce the thermostat is 45 degrees; any idea why a
heat pump may require higher than 60?

--
Have a great day, except you spammers
To email, remove the obvious

.......
"PrecisionMachinisT" wrote in message
...

"HvacTech2" wrote in message
...


Hi Les, hope you are having a nice day

On 14-Oct-04 At About 12:46:23, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter

L 0001e70 From: "Les"

L Live in a townhouse condo (middle unit)in Ohio. Will be gone for
the
L duration of the coming winter. Plan to shut off the water and drain
L the water from the pipes. Have no plants in home

L How low can I set the thermostat on the heat pump furnace? When I
go
L away for the weekend in the past, I would set it at about 60. Now
L since it is for an extended time, and with the price of fuel up, I
L would like to set it lower. I am inclined to set it at 50.

A heat pump thermostat should never be set lower than 60 degrees when in
heat
mode. any lower and you risk compressor damage.


Turn it clear off ???

--

SVL

Hi Les, hope you are having a nice day

On 18-Oct-04 At About 08:30:13, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter

L 0001ec2 From: "Les"

L The lowest I am able to reduce the thermostat is 45 degrees; any idea
L why a heat pump may require higher than 60?


It is due to the High side pressure. it is just the same as running the A/C
in any temperature lower than 60 degrees outside. the head pressure runs too
low and causes liquid to return to the compressor which causes excessive
compressor wear or even damage.


-= HvacTech2 =-


... Marriage is one of the chief causes of divorce.

___ TagDude 0.92á+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

HvacTech2;
See you are still following this thread. I posted the following a few =
days ago in response to your reply to me earlier. Maybe you didn't see =
it. Any chance you could provide further insight?
Thanks!
Repost:
"I think I understand the issue in cooling mode; the cooler air (less =
than 60 degrees) in the house will not transfer enough heat to the low =
side and so the return to compressor could be liquid instead of vapor. =
And compressor doesn't like liquid input.
In heat mode, if air at condenser is 60 degrees, the high side input =
vapor may not become fully liquid. However I don't see how this is a =
problem as the evaporator changes the low side refrigerant to a vapor =
anyway. So compressor still sees low side vapor.
Now I am a way out of my depth!! Maybe you could explain the issue, in =
heat mode, in a little more depth?
Just surprised at the no-no of running less than 60 degrees as I have =
not seen this as a caution in the operating instructions and have done =
it many times over 8 years without problem.
Also does this limitation differ from unit to unit?
Thanks again!"

"HvacTech2" wrote in message =
...
=20
=20
Hi Les, hope you are having a nice day
=20
On 18-Oct-04 At About 08:30:13, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter
=20
L 0001ec2 From: "Les"
=20
L The lowest I am able to reduce the thermostat is 45 degrees; any =
idea
L why a heat pump may require higher than 60?
=20
=20
It is due to the High side pressure. it is just the same as running =
the A/C
in any temperature lower than 60 degrees outside. the head pressure =
runs too
low and causes liquid to return to the compressor which causes =
excessive
compressor wear or even damage.
=20
=20
-=3D HvacTech2 =3D-
=20
=20
.. Marriage is one of the chief causes of divorce. =
=20
=20
___ TagDude 0.92=E1+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

Hi Treetops, hope you are having a nice day

On 18-Oct-04 At About 23:45:41, Treetops wrote to All
Subject: Temperature setting for heatpump

T From: "Treetops"

T HvacTech2; See you are still following this thread. I posted the
T following a few = days ago in response to your reply to me earlier.
T Maybe you didn't see = it. Any chance you could provide further
T insight? Thanks! Repost: "I think I understand the issue in cooling
T mode; the cooler air (less = than 60 degrees) in the house will not
T transfer enough heat to the low = side and so the return to
T compressor could be liquid instead of vapor. = And compressor doesn't
T like liquid input. In heat mode, if air at condenser is 60
T degrees, the high side input = vapor may not become fully liquid.
T However I don't see how this is a = problem as the evaporator
T changes the low side refrigerant to a vapor = anyway. So compressor
T still sees low side vapor. Now I am a way out of my depth!! Maybe
T you could explain the issue, in = heat mode, in a little more depth?
T Just surprised at the no-no of running less than 60 degrees as I
T have = not seen this as a caution in the operating instructions
T and have done = it many times over 8 years without problem. Also
T does this limitation differ from unit to unit? Thanks again!"

I missed your original post. the only thing going for you on a heat pump is
the suction accumulator. but think about this. when running a condenser less
than 60 degrees you are drastically lowering the head pressure and are not
correctly metering the refrigerant which causes the evap to freeze which in
turn causes liquid slugging. as I said before the suction accumulator helps
but will eventually be overcome by liquid. what this all boils down to is
that you shouldn't run the unit below 60 degrees indoor or outdoor temp.


-= HvacTech2 =-


... Cooking Instructions: Preheat microwave to 450 degrees...

___ TagDude 0.92á+[DM]
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Hi SJF, hope you are having a nice day

On 19-Oct-04 At About 11:13:47, SJF wrote to All
Subject: Temperature setting for heatpump

S From: "SJF"


S It seems to me that this 60 degree limitation may be the result of
S design compromise with cheaper units with marginal condensers and
S evaporators more likely to be limited. I have a Carrier 3.5 ton unit
S heat pump with Carrier supplied thermostat which permits setting
S the heat as low as 40 degrees. It sure doesn't seem they would
S provide that range if it were likely to damage the unit.

You can of course run your system whatever way you like but I am just giving
you the facts. any heat pump system has this limitation. most thermostats
go up to 90 degrees but would you run it that high?


-= HvacTech2 =-


... Took an hour to bury the cat. Wouldn't stop moving!

___ TagDude 0.92á+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

"Treetops" wrote in message
...
HvacTech2;
See you are still following this thread. I posted the following a few days
ago in response to your reply to me earlier. Maybe you didn't see it. Any
chance you could provide further insight?
Thanks!
Repost:
"I think I understand the issue in cooling mode; the cooler air (less than
60 degrees) in the house will not transfer enough heat to the low side and
so the return to compressor could be liquid instead of vapor. And compressor
doesn't like liquid input.
In heat mode, if air at condenser is 60 degrees, the high side input vapor
may not become fully liquid. However I don't see how this is a problem as
the evaporator changes the low side refrigerant to a vapor anyway. So
compressor still sees low side vapor.
Now I am a way out of my depth!! Maybe you could explain the issue, in heat
mode, in a little more depth?
Just surprised at the no-no of running less than 60 degrees as I have not
seen this as a caution in the operating instructions and have done it many
times over 8 years without problem.
Also does this limitation differ from unit to unit?
Thanks again!"

"HvacTech2" wrote in message
...


Hi Les, hope you are having a nice day

On 18-Oct-04 At About 08:30:13, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter

L 0001ec2 From: "Les"

L The lowest I am able to reduce the thermostat is 45 degrees; any idea
L why a heat pump may require higher than 60?


It is due to the High side pressure. it is just the same as running the
A/C
in any temperature lower than 60 degrees outside. the head pressure runs
too
low and causes liquid to return to the compressor which causes excessive
compressor wear or even damage.


-= HvacTech2 =-


.. Marriage is one of the chief causes of divorce.

___ TagDude 0.92á+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

It seems to me that this 60 degree limitation may be the result of design
compromise with cheaper units with marginal
condensers and evaporators more likely to be limited. I have a Carrier 3.5
ton unit heat pump with Carrier supplied thermostat which permits setting
the heat as low as 40 degrees. It sure doesn't seem they would provide that
range if it were likely to damage the unit.

"HvacTech2" wrote


You can of course run your system whatever way you like but I am just
giving
you the facts. any heat pump system has this limitation. most thermostats
go up to 90 degrees but would you run it that high?

"It's a heatpump AND a toaster oven! Two treats in ONE!!!!"

;-]

HvacTech: thanks for the input. Not being hvac expert, I can't question =
further but do wonder why this limitation is not clearly noted in op =
manuals. Only place I have ever heard of this is your post. Maybe I =
missed caution in past? Why does this not seem to be widely advertised? =
Having set heating below 60 in past many times over 8 years, why does my =
unit still function fine?

SJF: does your manual state not to run heating (or cooling) below 60 =
degress?


"SJF" wrote in message =
news:cnndd.5872$SW3.1974@fed1read01...
=20
"Treetops" wrote in message
...
HvacTech2;
See you are still following this thread. I posted the following a few =
days
ago in response to your reply to me earlier. Maybe you didn't see it. =
Any
chance you could provide further insight?
Thanks!
Repost:
"I think I understand the issue in cooling mode; the cooler air (less =
than
60 degrees) in the house will not transfer enough heat to the low side =
and
so the return to compressor could be liquid instead of vapor. And =
compressor
doesn't like liquid input.
In heat mode, if air at condenser is 60 degrees, the high side input =
vapor
may not become fully liquid. However I don't see how this is a problem =
as
the evaporator changes the low side refrigerant to a vapor anyway. So
compressor still sees low side vapor.
Now I am a way out of my depth!! Maybe you could explain the issue, in =
heat
mode, in a little more depth?
Just surprised at the no-no of running less than 60 degrees as I have =
not
seen this as a caution in the operating instructions and have done it =
many
times over 8 years without problem.
Also does this limitation differ from unit to unit?
Thanks again!"
=20
"HvacTech2" wrote in message
...


Hi Les, hope you are having a nice day

On 18-Oct-04 At About 08:30:13, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter

L 0001ec2 From: "Les"

L The lowest I am able to reduce the thermostat is 45 degrees; any =
idea
L why a heat pump may require higher than 60?


It is due to the High side pressure. it is just the same as running =
the
A/C
in any temperature lower than 60 degrees outside. the head pressure =
runs
too
low and causes liquid to return to the compressor which causes =
excessive
compressor wear or even damage.


-=3D HvacTech2 =3D-


.. Marriage is one of the chief causes of divorce.

___ TagDude 0.92=E1+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail
=20
It seems to me that this 60 degree limitation may be the result of =
design
compromise with cheaper units with marginal
condensers and evaporators more likely to be limited. I have a =
Carrier 3.5
ton unit heat pump with Carrier supplied thermostat which permits =
setting
the heat as low as 40 degrees. It sure doesn't seem they would =
provide that
range if it were likely to damage the unit.
=20

"Treetops" wrote in message
...
HvacTech: thanks for the input. Not being hvac expert, I can't question
further but do wonder why this limitation is not clearly noted in op
manuals. Only place I have ever heard of this is your post. Maybe I missed
caution in past? Why does this not seem to be widely advertised? Having set
heating below 60 in past many times over 8 years, why does my unit still
function fine?

SJF: does your manual state not to run heating (or cooling) below 60
degress?



It says nothing about minimum or maximum temperature settings.




"SJF" wrote in message
news:cnndd.5872$SW3.1974@fed1read01...

"Treetops" wrote in message
...
HvacTech2;
See you are still following this thread. I posted the following a few days
ago in response to your reply to me earlier. Maybe you didn't see it. Any
chance you could provide further insight?
Thanks!
Repost:
"I think I understand the issue in cooling mode; the cooler air (less than
60 degrees) in the house will not transfer enough heat to the low side and
so the return to compressor could be liquid instead of vapor. And
compressor
doesn't like liquid input.
In heat mode, if air at condenser is 60 degrees, the high side input
vapor
may not become fully liquid. However I don't see how this is a problem as
the evaporator changes the low side refrigerant to a vapor anyway. So
compressor still sees low side vapor.
Now I am a way out of my depth!! Maybe you could explain the issue, in
heat
mode, in a little more depth?
Just surprised at the no-no of running less than 60 degrees as I have not
seen this as a caution in the operating instructions and have done it many
times over 8 years without problem.
Also does this limitation differ from unit to unit?
Thanks again!"

"HvacTech2" wrote in message
...


Hi Les, hope you are having a nice day

On 18-Oct-04 At About 08:30:13, Les wrote to All
Subject: Tempiture Setting for Furnace in WInter

L 0001ec2 From: "Les"

L The lowest I am able to reduce the thermostat is 45 degrees; any
idea
L why a heat pump may require higher than 60?


It is due to the High side pressure. it is just the same as running the
A/C
in any temperature lower than 60 degrees outside. the head pressure runs
too
low and causes liquid to return to the compressor which causes excessive
compressor wear or even damage.


-= HvacTech2 =-


.. Marriage is one of the chief causes of divorce.

___ TagDude 0.92á+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

It seems to me that this 60 degree limitation may be the result of design
compromise with cheaper units with marginal
condensers and evaporators more likely to be limited. I have a Carrier
3.5
ton unit heat pump with Carrier supplied thermostat which permits setting
the heat as low as 40 degrees. It sure doesn't seem they would provide
that
range if it were likely to damage the unit.

"HvacTech2" wrote in message
...


Hi SJF, hope you are having a nice day

On 19-Oct-04 At About 11:13:47, SJF wrote to All
Subject: Temperature setting for heatpump

S From: "SJF"


S It seems to me that this 60 degree limitation may be the result of
S design compromise with cheaper units with marginal condensers and
S evaporators more likely to be limited. I have a Carrier 3.5 ton unit
S heat pump with Carrier supplied thermostat which permits setting
S the heat as low as 40 degrees. It sure doesn't seem they would
S provide that range if it were likely to damage the unit.

You can of course run your system whatever way you like but I am just
giving
you the facts. any heat pump system has this limitation. most thermostats
go up to 90 degrees but would you run it that high?


-= HvacTech2 =-

Well, in fact I do. I set the 'cooling' at 85 degrees when we are gone in
the summer. I think that's what that upper range is for -- so that you
don't cool when you don't need it. Conversely, I set the heating at about
55 degrees when were gone in the winter so I don't heat when it's not
needed. My unit has survived 12 years of this in the desert where our
temperatures range 20 to 115 degrees.