Washington Hp Home DIY Geothermal

Andy:

It is all in who is the rep for the manufacturer. Call my guy: Dan Bors 216.299.2357.

Mark

 

The check valves I was talking about would have been instead of the second 3-way valve, not in addition to. If it works it would be quite a bit cheaper and easier to wire, but then there is the 2% leakage issue.

How does the wiring work with the 2 valves? Does one valve use an end switch to signal the other?

 

I thought that issue was resolved.

Or maybe I am incorrectly assuming your pumping and piping configuration. Correct me if I am wrong.
1- Single Reversible WWHP?
2- Two Tank H/C with auto changeover?
3- Single HP Load Pump between HP and H/C Change Over Valves?

Or will you have 2 HP Load Pumps H and C between HP In and Out tees and buffer tanks? This configuration would be more appropriate for a multiple HP system. If yes, then you will have pumps in parallel which will require check valves and would not require zone valves in a single HP system.

A word of caution here. I would not pipe or spec any components until the control system and sequence of operation is nailed down.

 

The valves would typically be wired in parallel. The "O" reversing signal from controller can power actuation. The end switches can be used to break the controllers "Y" compressor call to HP until the valves have actuated.

 

Thank you that makes sense, I will be using the single heat pump, single load pump.

Yes I am trying to get everything figured out before I start installing. I am using the HBX Eco 550 which looks pretty straight forward. It has reversing valve terminals for the 3-way valves. Thank you for telling me about using the end switches to delay heat pump start.

 

The HBX ECO-0550 is a wise choice for your application. ODR for heating and cooling, WWSD, CWSD, Aux droop and time delay and many other control options make it very versatile.

I just talked to HBX. The ECO-0550 when changing over, will make or break reversing terminals 60 to 72 seconds before making HP1. The remaining 18 seconds of valve rotation may not be a big deal when you consider most HP internal control boards have a delay built in between receipt of "Y" and energizing the compressor.

Or configure the ECO-0550 as a HP 2 Stage with 1 min lag time and no rotation. Then control your HP as HP2. This will give you 120 seconds for valve actuation before the compressor is called. No playing with end switch logic in h or c.

 

Progress pics-

Domestic hot water complete less one 5" nipple. 40 gallon buffer in front and 50 gallon electric behind it.




Ground loop manifolds and flow center mounted.
I need to finish insulating after its plumbed. The strut channel in front is where the hot/cold buffer tanks will be secured.

I don't know if this needs a flex hose type connection to compensate for movement in the hdpe pipes? Or could it all be plumbed with copper?




Domestic hot water piped to the hot water generator and starting to mock up P/T port fittings and wye strainers.
The heat pump came with 1" threaded strainers but I went with 1.25" sweat ones for a cleaner install with the 1.25" copper piping.

 

I did a drawing to help me with the hot/cold piping.

I tried to show as much detail as possible including make up water, load direct piping, air separators, purge valves, etc.

Not shown on this drawing are the domestic hot water, source and delivery sides of the system.

If anything important is missing please let me know. It's not plumbed yet so there is time to make changes.

Edit- fan coil return should be shown entering at the top of the cold tank.

 

A couple of thoughts that may just be in the thread already...

I'd have the fan coil plumbed off for heating and cooling. It's an easy option.

You can basically eliminate the cold tank if you can match the loads with heat pump staging/ fan coil.

 

Eliminating the cold tank has been talked about, that part is too late to change.

I didn't plan for heating with the fan coil because I expected water temps to be too low. Earlier on in the design phase that was my idea but I was talked out of it because it would blow cold air. So I went with radiant through the whole house for heating and the fan coil is now cooling only.

 

In the future then... you don't need a buffer tank when you only have one zone. Such as 1 cooling zone you've shown. But if you already have it - go for it.

 

Looks good! So where do you include your DWH?

 

Thank you! It's good to know I am on the right track.

I have the desuperheater option on my heat pump and plumbed it like this-

 

Your pipe schematic is topologically correct as to flow directions and labels at 3way valves and bypass tees. However, it would be prudent to redraw to be visually literal in regard to actual Belimo B3 valve orientation as follows-

Your schematic

A and AB should be straight through. B is the branch. Most pipe fitters will be very visual in their implementation of a schematic, very often to the point of not reading the labels.
Also I believe you should encourage straight through flow to your loads at the "load direct" buffer tank bypass tees by using the branch port of the tee to the buffer tank.

 

Do your unions have a o-ring seal and 1/4" taps? If so would you be so kind as to share your source?

I have been searching for those for years.

 

Thank you, it will save me a little head scratching during the install to have the valves drawn in the correct orientation.

The tees will be straight through, I changed the drawing to show that as well.

 

Yes they have an o-ring seal and (2) 1/4" taps. They are a little bulky and I don't really need a union there but it was the easiest way I found to get the 1/4" P/T ports I wanted for the 1.25" pipe.

http://www.supplyhouse.com/Macon-Ba...rt-Balancing-Union-with-3-1-4-Accessory-Ports

Supplyhouse.com deserves a mention, I have been getting a lot of my stuff there and they have been great.

 

You had the ports correct, just not visually in the drawing.

I know you have your DSH piped already, but I usually advise for an indirect tank running as a zone off the heat pump. SBB 400 plus is what we use. That way you make 100% of your hot water via geo.

And then the very last question comes up: How do you control everything, and how do you prioritize?

 

"There are a thousand ways to make domestic hot water and none of them are any good."

I don't remember where I read that quote but I kept remembering it when I was planning and designing. I almost went with an indirect water heater, or a coil inside the buffer tank but I ended up going the desuperheater route. I plan to monitor the performance and see how it works, I may decide to do something different in the future (maybe solar).

My next step is to add some wires to my drawing. Using the HBX eco-550 makes controlling everything relatively easy. But I do have a few details that I still need to figure out, as soon as I learn the right questions to ask.

 

John Manning PE used that quote, and I stole it from him.

The best way is to capture the "free" hot water in the summer via desuperheater, and then use a dedicated w-w heat pump to make 100% of your remaining hot water. But that solution comes at a price.

You could skip the DSH and just install a dedicated w-w for hot water, which I would have done if you have the w-w infrastructure already installed.