Wow! Heat Pump _isn't_ Rocking?!?!?!

ChrisDIY · 11-23-2010, 09:00 PM

My wife and I are starting our second winter in our new home. I replaced one unit with a Goodman 2.5 ton heat pump Rinnai hydronic coil air-handler. With the hydronic coil off running just the heat pump it starts out at 82 degrees and gets up to 89 degrees of heat with room temperature at 70.

To the contrary the older unit in the other half of the house a 3.0 ton with electric Goodman air-handler. It on the other hand starts out only producing 76 degrees of heat and slowly gets up to 80, with the same starting room temp. Outside air temp is 38 degrees.

What temp output should I be seeing? Why does the quality of the heat feel better with the new unit? I changed both filters just this past weekend. Aren't heat pumps not supposed to decrease humidity? Humidity is now 38% on the side with old unit. No humidity sensor on side of house with new unit.

kenmac · 11-23-2010, 09:18 PM

could be low on refrigerant or just an old worn out unit

ChrisDIY · 11-23-2010, 09:55 PM

Quote:

Originally Posted by kenmac

could be low on refrigerant or just an old worn out unit

Refrigerant was checked last winter and it performed the same last Fall/Winter. I just have this voice in the back of my head saying something is not sized properly.

Part of me is thinking I need to install a mini-split system in the large room over the garage and block all the vents leading to this room.

After the system has been running all evening ( 2 straight hours) the bedroom is at 73 degrees but the room over the garage is only at 67 degrees. The air out of the vent is 71 degrees. The newer unit reached 73 and shut off a long time ago.

Plumber101 · 11-23-2010, 10:03 PM

I don't think you are comparing apples to apples but the thing you need to relize is that as the outsid temp drops the efficiency of a heat pump drops.

What is the second stage heat? Gas or Electric?

ChrisDIY · 11-23-2010, 10:14 PM

Quote:

Originally Posted by Plumber101

I don't think you are comparing apples to apples but the thing you need to relize is that as the outside temp drops the efficiency of a heat pump drops.

What is the second stage heat? Gas or Electric?

I'm using Aprilaire 8870 using software I wrote. Second stage won't kick in until temp drops below 30 degrees or temp has to change in house more than 5 degrees. So right now second stage on either unit not a factor.

ChrisDIY · 11-30-2010, 10:23 AM

The room over the garage is 900 sq. ft. The current heat pump is a 3.0 ton. If I remove this room from this unit and put it on a mini-split wouldn't this make the original unit "over-sized?"

At some point in the future, 5-10 years, I plan on taking the wall completely down in-between this space and the living room (also on second floor) and make it a lodge style room. Even then I don't think I'll get good air circulation.

Floor joists in crawlspace run perpendicular to direction I would need to run a duct to put a return vent in room which could solve issue. Assuming second floor joists run same direction???

ChrisDIY · 12-07-2010, 11:09 AM

I used one of the online sizing calculators and it turns out my unit is probably mismatched.

The square footage of my living space is 2,616 which a 4.0 ton is recommended. The house currently has a 3.0 ton. However as stated before I am not getting hardly any air-flow to the library room so if I subtract the 900 square feet out the 3.0 ton is now properly sized but the library room has no heat.

I know it's all case by case, but what is the path of least resistance? Trying to improve duct work or just adding a 1.5 ton mini-split system to the room? Improving duct work will now force an entire new HVAC unit at 4.0 ton. Something on the long list anyway, so now new 3.0 or 4.0???

kenmac · 12-07-2010, 11:48 AM

Have you checked the duct under the house? Something may have come apart & your air is blowing under the house

ChrisDIY · 12-07-2010, 01:37 PM

Quote:

Originally Posted by kenmac

Have you checked the duct under the house? Something may have come apart & your air is blowing under the house

This part of house has a crawl so all ducts are ran in joist space of second floor. The rooms: One bedroom, dining room, living room (858 sq. ft. by itself since it shares vaulted second floor ceiling with first floor Photo on right), and laundry all have air forcefully exiting. Library over garage has tinted clear plastic type ducts and has very little air exiting. I cannot see down it very far with light and a mirror.

Resistant heat is probably not working on top of this. Will check it tonight

ChrisDIY · 12-08-2010, 09:51 AM

FOUND THIS!

Don't know why this happened or whether it will occur again. Shortened wire and put new tab connector on. Will check it in a couple of days. Delta rise is better but still isn't ROCKIN'...

11-23-2010, 09:00 PM	#1
ChrisDIY Still going... Join Date: Feb 2010 Location: Indianapolis Area Posts: 888 Blog Entries: 19	Wow! Heat Pump _isn't_ Rocking?!?!?! My wife and I are starting our second winter in our new home. I replaced one unit with a Goodman 2.5 ton heat pump Rinnai hydronic coil air-handler. With the hydronic coil off running just the heat pump it starts out at 82 degrees and gets up to 89 degrees of heat with room temperature at 70. To the contrary the older unit in the other half of the house a 3.0 ton with electric Goodman air-handler. It on the other hand starts out only producing 76 degrees of heat and slowly gets up to 80, with the same starting room temp. Outside air temp is 38 degrees. What temp output should I be seeing? Why does the quality of the heat feel better with the new unit? I changed both filters just this past weekend. Aren't heat pumps not supposed to decrease humidity? Humidity is now 38% on the side with old unit. No humidity sensor on side of house with new unit. __________________ --Chris the DIY Guy Still going, on Ibuprofen...

11-23-2010, 09:18 PM	#2
kenmac HVAC / Plumbing Join Date: Feb 2009 Posts: 1,801	Wow! Heat Pump _isn't_ Rocking?!?!?! could be low on refrigerant or just an old worn out unit

11-23-2010, 10:03 PM	#4
Plumber101 GC/Master Plumber/Mech Join Date: Feb 2009 Location: Hays, KS Posts: 1,467	Wow! Heat Pump _isn't_ Rocking?!?!?! I don't think you are comparing apples to apples but the thing you need to relize is that as the outsid temp drops the efficiency of a heat pump drops. What is the second stage heat? Gas or Electric? __________________ John Wayne once said "Life is tough and it is even tougher if you are stupid" Tempstar and Trane Dealer

11-30-2010, 10:23 AM	#6
ChrisDIY Still going... Join Date: Feb 2010 Location: Indianapolis Area Posts: 888 Blog Entries: 19	Wow! Heat Pump _isn't_ Rocking?!?!?! The room over the garage is 900 sq. ft. The current heat pump is a 3.0 ton. If I remove this room from this unit and put it on a mini-split wouldn't this make the original unit "over-sized?" At some point in the future, 5-10 years, I plan on taking the wall completely down in-between this space and the living room (also on second floor) and make it a lodge style room. Even then I don't think I'll get good air circulation. Floor joists in crawlspace run perpendicular to direction I would need to run a duct to put a return vent in room which could solve issue. Assuming second floor joists run same direction??? __________________ --Chris the DIY Guy Still going, on Ibuprofen...

12-07-2010, 11:09 AM	#7
ChrisDIY Still going... Join Date: Feb 2010 Location: Indianapolis Area Posts: 888 Blog Entries: 19	Wow! Heat Pump _isn't_ Rocking?!?!?! I used one of the online sizing calculators and it turns out my unit is probably mismatched. The square footage of my living space is 2,616 which a 4.0 ton is recommended. The house currently has a 3.0 ton. However as stated before I am not getting hardly any air-flow to the library room so if I subtract the 900 square feet out the 3.0 ton is now properly sized but the library room has no heat. I know it's all case by case, but what is the path of least resistance? Trying to improve duct work or just adding a 1.5 ton mini-split system to the room? Improving duct work will now force an entire new HVAC unit at 4.0 ton. Something on the long list anyway, so now new 3.0 or 4.0??? __________________ --Chris the DIY Guy Still going, on Ibuprofen...

Wow! Heat Pump _isn't_ Rocking?!?!?!