DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   HVAC (http://www.diychatroom.com/f17/)
-   -   What is this HVAC Heat Pump System - Water Pipes To Indoor Coil? (http://www.diychatroom.com/f17/what-hvac-heat-pump-system-water-pipes-indoor-coil-92245/)

kentkeith 01-13-2011 11:55 PM

What is this HVAC Heat Pump System - Water Pipes To Indoor Coil?
 
I recently bought a house with two heat pumps in it, one on each side of the house. My home inspector at first thought that it had a geothermal set up, since there were copper pipes leading to the interior coil units. However we noticed that the pipes don't go into the ground, in fact they enter the two propane water heaters. When we opened up the indoor coil cabinets, we noted that there were recirculating liquid pumps on the lines, and not the usual heat coils or combustion units.

This all makes me think that this unit uses the water heaters hot water as a backup of sorts, so that when the heat pump needs a "boost" in cold weather, it draws some hot water from those tanks. I tried internet searches to see if there were any schematics or pages on these systems, but could not find any.

The reason I am interested is that my two propane water heaters have used $500 worth of propane since November. This seems like a lot of propane, since there is only one person living in the house and no other propace appliances or uses. My electrical usage last month was $200, which seemed about right for two heat pump units, or maybe even a little low since this house is over 5000 sq ft.

I am wondering if the hot water is circulating all the time, and this is why they are using too much propane to heat all the water. Anyone else ever seen a system like this?

Know It ALL 01-14-2011 12:13 AM

I'm not up to date on these systems, but it sounds like an Apollo set up.

kentkeith 01-14-2011 12:23 AM

Quote:

Originally Posted by Know It ALL (Post 569792)
I'm not up to date on these systems, but it sounds like an Apollo set up.

I looked on their website and it looks like they use just the Apollo water heater for heat, in combination with an air-to-water coil.

My system still has traditional heat pump coil/compressors outside that are also plumbed to the inside unit coils. So it is like a traditional electric heat pump system other than the weird backup plumbed to the water heater.

beenthere 01-14-2011 05:28 AM

Post pics of the indoor units where these pumps are. Along with the brand and model number of the indoor units. You very well may have a hydro coil aux heat set up.

First company and others make air handlers with both coils built into the air handler(standard refrigerant oil and hydro coil).

kentkeith 01-15-2011 02:41 AM

6 Attachment(s)
I think that I have figured out what system I have. I have two Aquatherm units, manufactured by First Co. They appear to be out of Dallas, Texas.
The first unit I have is in the garage next to my two hot water heaters. It is a 48MBQ4 unit, with the original R22 heat pump coil in the interior cabinet, and also a water-to-air coil in the interior unit as backup, which is plumbed to one of my American Water Heater “ProLine Super Eagle” Model G62-50T63-4PV, 50 gallon LPG hot water heaters. The water is pulled from two separate in/out ports (distinct from domestic supply ports) in the water heater by a “Taco” brand water pump. The pump appears to be activated by wiring from the thermostat and a small timer (Grasslin MIL 72A STuZ-24). I am thinking the timer is there to circulate the water every day for a little while. The original Trane exterior compressor/coil unit was broken when I moved in, so I had a new Goodman unit installed. My HVAC contractor used a new R410a Goodman unit, with the old R22 interior unit. Is this ok if he pulled a vacuum on the system?
The second unit I have is on the other end of the house, and is a 36MBQ3A unit that is attached to its original “old school” exterior unit. It also is fed by a “Taco” brand water pump that pulls water from the identical water heater a few hundred feet away in the garage, for AUX backup.
The house also has recirculation pumps, on each hot water heater, to the domestic fixtures, so I have instant hot water at all fixtures.
I have used 300 gallons of LPG since November 1st. This house has LPG appliances that include three fireplaces, one cook top, and the two water heaters. The stove has not been used in that time, and neither have the fireplaces (pilots turned off). So this is just to heat water. I was told by the LPG company, that the previous owner used 1255 gallons of propane in 2008, and 1810 gallons in 2009. Propane is going for $2.41 per gallon here.
I am wondering if the backup heat is causing the water pumps to recirculate the water from the hot water heaters to the water-to-air backup coils, and this is causing my LPG use to be high. Any comments or suggestions are appreciated.

kentkeith 01-15-2011 02:42 AM

More Pics
 
6 Attachment(s)
Additional Pictures:

beenthere 01-15-2011 05:22 AM

Hope he put a R410A TXV on that air handler. Or it won't be cooling right in the summer.

Are you setting back the temp at night or while your at work. Depending how the thermostats are set up. if you are, it can cause you to use a large amount of LP.

kentkeith 01-15-2011 11:00 AM

Quote:

Originally Posted by beenthere (Post 570536)
Hope he put a R410A TXV on that air handler. Or it won't be cooling right in the summer.

Are you setting back the temp at night or while your at work. Depending how the thermostats are set up. if you are, it can cause you to use a large amount of LP.

I have had both thermostats set at a flat sixty degrees, no setbacks from there.

I am not sure what he put on the air handler, what would a R410A TXV look like? He did say he would have to come back in the summer to make sure it was cooling right.

3 legged dog 01-15-2011 11:54 AM

Is it piped to solar panels also?

I've never see that setup.

Why not a LP furnace?

hvactech126 01-15-2011 12:29 PM

that is kinda what I was thinking......
Quote:

Why not a LP furnace?
What is the advantage of this system supposed to be over using a dual fuel LP furnace and HP setup?

kentkeith 01-15-2011 12:46 PM

Quote:

Originally Posted by 3 legged dog (Post 570677)
Is it piped to solar panels also? I've never see that setup. Why not a LP furnace?

Well I just bought this place, so I didn't have a choice in the design. But in my area (Pacific Northwest) heat pumps are supposed to be the most efficient way to heat. http://www.cityofseattle.net/light/c...ng/cv5_fcc.asp

I did find a website with information about my system, and these systems in general. The manufacturer believes them to be very efficient. http://www.firstco.com/products/aqua_therm.asp

But my propane use should only be coming into play when the heat pump can't keep up with the cold air outside. So it is just an AUX or BACKUP heat, for unseasonably cold weather here. This is my unit: http://www.firstco.com/mbq_f.asp

hvactech126 01-15-2011 12:55 PM

is your stat set on heat or emergency heat?

beenthere 01-15-2011 05:57 PM

Quote:

Originally Posted by hvactech126 (Post 570693)
that is kinda what I was thinking......
What is the advantage of this system supposed to be over using a dual fuel LP furnace and HP setup?

The main advantage is that the hydro coil being after the condenser coil allows for the heat pump and aux to be heating at the same time. Unlike a conventional dual fuel system.

beenthere 01-15-2011 05:59 PM

Post the brand and model number of your outside units. And the model number of both of the air handlers. Along with the size of your house.

kentkeith 01-16-2011 10:16 PM

2 Attachment(s)
Exterior unit brand name & model numbers are:

1) Goodman Model GSZ130421AB
2) Payne PH10JA030-A R22

House is around 5400 sq ft of heated space.


All times are GMT -5. The time now is 07:39 AM.