I know heat pumps have been discussed may times. If there is a good archive on the board let me know.
Would anyone have a checklist for inspecting a heat pump and the emergency heat?
I have a 3100 sq. ft. home with a zoned system that has 3 heat pumps and the home is a electric. The home is located in Northeast Ohio and I will be testing the heat mode. I do understand about the reversing valve.
Thank you for your time
Dave
David,
Being up in Ohio at this time of year you at least won’t have to worry about the air conditioning part. Most heat pumps I have done have a 2 degree set on the thermostat so if you raise the temp that much over current temp, the back-up / strip heaters will turn on and usually show a light on the panel. Don’t forget to defer the air conditioning portion.
The secret of heat pumps is to move lots of air. I always recommend 60 day filter changes instead of 90.
Here’s a pretty good heat pump inspection description from ITA: http://www.home-inspect.com/itatips/11-04.asp
If you have 3 units on 3100 SF, I doubt you have a zoning system because it would not be needed.
Zoning is installed to use 1 unit to do two levels or areas or 2 units to do even more.
A true zoned system has a control box somewhere and motorized dampers in some of the ducts.
When inspecting a system with zoning be sure to disclaim the performance since it is based on programming, installation details and very dependent on outside temp, insulation quality etc. I tell clients to learn the system or find a qualified hvac guy because they can be tweaked over time to provide good results.
Bruce,
What is the context of your disclaimer, If I may ask.
I see alot of zoned systems and have wrote some up for producing marginal temp drops in certain areas of the home…
Just wondering how you’d word it.
http://oee.nrcan.gc.ca/publications/infosource/pub/home/gif/heatpump_fig7_e.gif
http://oee.nrcan.gc.ca/publications/infosource/pub/home/gif/heatpump_fig10_e.gif
http://oee.nrcan.gc.ca/publications/infosource/pub/home/gif/heatpump_fig11_e.gif
http://oee.nrcan.gc.ca/publications/infosource/pub/home/gif/heatpump_fig12_e.gif
I hope this helps.
Mike this is all I add since the SOP’s already disclaim a lot of hvac performance.
Zoning info for reports:
A zoning system is present that allows a single smaller hvac unit to serve a larger area by controlling duct valves with electronics that have two thermostats present in the house. It is recommended to obtain the owners manual and consider learning how to or obtain assistance in making adjustments to obtain the optimum performance based on the actual use of the home if the performance is not satisfactory.
Thanks Bruce,
I use something similar though I don’t think it’s as detailed. On the road so I’ll have to look when I get home…
Great info.
We have a lot of “zoned” systems here in San Diego, up to six that I have found. I have never found one control for all six systems and, quite frankly, I would probably find that inconvenient. I don’t want to walk through 3,000 SF of space and stairs to get to the control for my master bedroom in the middle of the night.
The zoning systems here simply have a thermostat in the master bedroom, one in the living room/family room/game room, one for the kitchen/dining room, one for the guest suite, one for the bedrooms, etc. Since there is nothing unusual about standard thermostats, people in various parts of the house can operate their zone as they see fit.
Russel,
The control box might handle several thermostat demands but you do not have to “walk to it to make temperature adjustments”. It is not for everyday use and is usually in the attic. The control box can be programmed to decide which thermostat gets priority and at what differential. A house with six thermostats probably has more than one control box.
Never seen such a device connected to all the furnaces. Particularly never seen something like that in the attic. Zoned furnaces here act individually from each other, which can be inconvenient, but still is better than having all six going at the same time from one thermostat.
I lived in while renovating a dual-zoned, 4000 SF house a few years ago. The giant living room was in the middle seperating the bedrooms from the rest of the house. Unfortunately, both furnaces serviced the living room, and two sides of the living room were floor to ceiling windows to take in the view, and the living room faced south. So it got extremely hot in there during the summertime. So if one wanted to sit in that room, and the view definitely encouraged one to sit in there, one had to turn on both thermostats to cool the room down. Unfortunately, the rest of the house became an igloo by the time one was finished sitting in there. I installed reflective tinting on all the windows which helped, so when I sold the house after renovating (and I sold during the summertime), the living room was quite comfortable.
Window tinting. Best thing that ever happened to windows until multi-pane windows came along. Unfortunately, they don’t make 6’x35’ multi-pane picture windows, and breaking up the picture windows into lots of tiny windows would have destroyed the impact of the view.
Russell,
I never said the control box was connected to more than one system.
It is connected to more than one thermostat.
Other info just to help others:
A home with two or three hvac units usually does not have zoning.
The thing that indicates zoning are when there are more thermostats than hvac units.
Honeywell Zone Systems and Controllers
Smarthome
http://www.smarthome.com/3038.html
Commercial Applications…
http://www.autozonecontrols.com/
As to emergency heat, my experience has been to switch the thermostat to emergency and let it run. See if the duct heats up. You won’t necessariyl know the electrical portion of the emergency heat is functioning or burnt out elements unless you check it with an electrical meter. Thats beyond the scope. So you could feasibly have one or two elements burnt out and not know it. I always recommend service prior to closing of title on Heat Pumps which do not appear to be functioning properly or which are old.
Raymond Wand
Alton, ON
I think we simply do it differently out here, as well as having different terminology. Our thermostats control our systems, so there would be one thermostat for each system here, and each system usually has one furnace and one cooling condenser. It is interesting in that I never find zoned systems without cooling condensers, yet, because of our weather, there are a great many houses that have no cooling system.
Obviously HVAC zoning needs to be defined here so that all understand the term.
There are basically three different ways that zoning can be applied to a home. For example, a home could be zoned with equipment. This means you could have two - or more - completely separate comfort systems, each with an air conditioner, a furnace and a thermostat. One system might supply conditioned air to a downstairs area, while the other system handles the upstairs area.
Or a home could be zoned with controls and dampers, using a single comfort system. In this case, a home could be divided into as many as eight areas or “zones,” with each zone having its own sensor that monitors the temperature and controls it with a motorized mechanical damper.
The third way is simply a combination of these two methods with two or more systems, each zoned with controls.
So, a home with two Heat Pumps, HVAC systems independantly controlled, has at minimum 2 zones.
FYI
TG
What’s the difference between aux.heat and emergency heat? I see some thermostats with both indicators.
Thanks.
Aux heat supplements the heat pump (on at the same time). This is usually less than all the heat strips available. Emergency heat is strictly the alterative heat. It can be electric, gas or oil. It’s normally used when the heat pump is out of commission. There are exceptions to everything. Depends on the person wiring the unit up. I’ve seen units wired through outdoor t-stats that allowed all of the electric heat to come on with the heat pump if the temp was low enough.
I usually see heat pumps in the higher altitudes here where it gets colder. So when one gets home at midnight, one can turn on the emergency heat and get the place heated much faster than just using the standard heating controls.