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[lvdavidson]

Hello.  I am new to the forum.  I found it on my search for an outdoor boiler.  I have pretty much decided that I am going to put in a unit, not sure which one as of yet.  My question has to do with hooking up the system.  I live in an old (built in 1906) 2 floor house with a partial basement.  The insulation is not good and the house is not real air tight.  I have done lots of things to help  but my electric bill is still hitting my wallet hard.  Currently I heat with a heat pump, actually 2 of them.  A large (3 ton I think) unit for the main floor and a small (1/2 or 1 ton) for the upstairs.  I had 2 put in so I could better control the temperatures throughout both floors of the house.  This leads me to my question.

If I want to heat both the main floor and the upstairs and my hot water heater as well how should I hook up the unit?  Do I run 1 set of pex lines from the unit to the hot water heater, then to the main floor heat pump, and then to upstairs heat pump?  Or should I run 2 sets of lines?  (One for the hot water and upstairs heat pump, and one for the main floor heat pump).

I guess basically what I am asking is  will there be so much heat loss from the 1st  heat pump that the 2nd heat pump won't be able to heat the upstairs?

Thanks in advance.

Other info:
Main Floor is about 1600 sq ft
Upstairs is about 800 sq ft
Basement is about 1000 sq ft (just storage no need to keep at a high temp.  Right now it stays about 58-60 while the rest of the house is around 67-70)

[yoderheating]

If the space isn't very well insulated you can most likely throw the sq footage figures out the window. I have an old house and they use a lot more heat then a new one of the same size.
 Depending on the size of the furnace a single one inch line is all you could realistically pull anyway. I have found that a one loop of one inch pipe can work a stove fairly hard if it is pulling heat off constantly. In other words, if you do plan on running two loops I would make sure the furnace is large enough to supply good heat to both.
 What if you ever develop a leak in your attic? I have heard of cases where the coil freezes during a power outage. When the power came back on the pump started working and dumped over 100 gal of water down through the house. If you go into a attic make sure you use extra precautions to avoid this.

[1grnlwn]

You might be able to run a 1 1/4" from the stove and split it to 2-1" to feed the heat pumps.  The DHW would normally be 2-3/4 looped, if stove has DHW loop.  You could take the savings from your electric bill and try to tighten up the house.  I guess it would depend how far the stove is from the house.  I am thinking while I type here, but if you could come up with an electrical control that would only run one heat pump at a time , 2-1" lines would work.  This will also reduce the cost of pipe and pumps.  I think it would be fairly simple, you could wire it so the main floor would cycle normally and the upstairs would not cycle until the main floor had finished.  You would probably just need 1  or 2 servo valves . 

[juddspaintballs]

Use a manifold setup.  The main line (probably 1-1/4") from the boiler goes to a manifold and then all of the taps off of the manifold flow through their respective devices (coils in the air handlers and your water heater exchanger) and then back into a multi-tapped return manifold that feeds back into the boiler. 

[yoderheating]

 Its been a while since I looked it up but I believe two one inch lines will provide less resistance and more water flow than a 1 1/4 line. I have run as many as three heat pumps off of one 1inch line loop. However, that is on a home that the units didn't have to run constantly to keep up. Any way you do it you need to be sure both the furnace and the system is large enough to handle your needs. The first thing I would do is determine the amount of btu's needed to heat the home. Then you will have an idea of the size of furnace and system that you will need.

[lvdavidson]

After crunching some numbers here is what I have found.  I got numbers from my old power bills and estimated my monthly heating KWH (I subtracted my lowest month's usage from all heating months to get a good estimate on my heating hours).  Using the formula 1 KWH = 3413 BTUs I got these numbers for a 3 year average off of my power bill. 

December averaged 2100 KWH on heating for the last 3 years.  Which averages to 9500 BTUs per hour.
January averaged 3149 KWH which is about 14,500 BTUs per hour.
February averaged 2350 KWH which is about 11,800 BTU's per hour.

Do these numbers help??

How does these numbers help me  find the BTUs to heat my home?

I think I like the manifold idea (that would allow me to turn off the upstairs unit and drain just those lines in case of an extended power outage).  Like I said, I am just getting into the process of finding a stove and all the stuff that goes with it.  Any and all suggestions would be and are greatly appreciated.

[yoderheating]

 It sounds like the most heat you would use would be to 20000 btu's per hour on the coldest days. A 250,000btu furnace should give you 12 hour burn times when filled with good hardwood. A 500,000btu furnace would give you a 24 hour burn time.
 As far as hooking up the upstairs unit, I do an isolated loop between the unit and a flat plate in the basement. You can then fill that loop with antifreeze so you will never have to drain it. It does cost a little more because you need a pump, flat plate and a small pressure tank but at least you know it will never freeze and bust.

[willieG]

you mighth look at your two heating units now in service and add up both their BTU outputs and use that as some sort of starting point as to what size of OWB you need? remember these units you have now are likely more efficiant then the OWB you will buy (or make)
so go bigger. yonders suggestion may be the best one but i would add the output of what you got now just for comparison

[Scott7m]

I think you'd be covered with a unit that is expected to heat 5000 sq ft.  The btu output on the stove should easily cover what your needing. 

[mikenc]

If in doubt when you buy go bigger. Better to have extra than end up with a unit two small.  That way if down the road you decide to add on you will have the capacity to do so. If btu of current two units is doing the job that would be a good starting point. I would  include the  basement into your total btu needed. Using a header system for piping sounds like a good arangement. Just my opinion everyone has one.

[forest]

I have a 3000 sq ft house split into two levels. The line from the OWB comes into my crawl space goes to my domestic hot water tank where there is a water to water heat transfer loop and then it cycles back to the stove. This forms the primary loop in the system and runs constantly. Off that are two loops that heat half the house each that run off the primary loop and are controled by thermastats that run values that open and close thus contoling hot water flow. The heat is taken off via modern hot water base board rads. There is a further loop that does the upstairs. Heat rises thus requiring less rads. The system keeps the house uniformally heated on even the coldest nights. I use a one inch line from the stove. Youd don't need a large flow. In fact for heating purposes you don't want the water to move too quickly, giving it time to give off some of its heat to the rads. You do need to insulate your lines in the ground otherwise you end up heating the earth. I put the rads in after the house had been constructed. It required some uncomfortable work, but was possible and I have really enjoyed the hot water heat. I am not sure how you currently move your heat within your home, you may be able to tie into that system which is already in place.

[lvdavidson]

I currently use 2 separate heat pumps.  One for the main floor and one for the upstairs.  I would put a Water to Air exchanger in each.  Which brings me to my next question.  What size W/A exchanger should I have in my duct work?  I know it needs to go in the line just after the fan. 

My main floor unit:   Well my main trunk splits right at my fan.  I have measured the duct work at the split and can get something around 12" X 17" in that space.  Will that produce enough BTUs to heat the house?  I have read the specs on my fan and it moves about 800 to 1000 CFM. It is 1/3 HP with 2 speeds. 

My Upstairs unit is smaller (moves about 500 to 700 CFM) but I have plenty of room to work with there.  I can put in about any size exchanger here. 

How many BTU's should I be looking to get out of each one separately?  Is there anyway I could put the exchanger in the return air duct?  Or will that not work?  I have more room to work with on that end.

Sorry if none of this makes sense.  I am trying to figure out what I can.

[willieG]

my original house furnace is an inground water furnac(heat pump) my fan also moves a lot of air and it runs 24/7 on low speed. it only ever goes in high speed if the water frunace is workiing (never) your heat exchanger(rad) should fill your ductwork, if the exchanger has a gap between it and the ductwork the air will pass by the exchanger and take no heat with it. The fan blows  but the air takes the path of least resistance.  heat pump usually move much more air than a hot air furnace due to the fact they usually are moving much cooler air so they must move a lot more of it to match the
 btu loss of the home My house furnace fan is actually a 1 horse power 220 volt brute, designed to move a lot of air i have the ductwork full of rad 12 x 24(actually a little less i have 2 12 x 14 rads with one slghtly in front of the other)