what do you guys think about.........

[Ice Cold]

I have a few installation questions....

First let me explain how I'm planning on setting up my system. Currently I have a Oil boiler rated at 184,000 btu's plumbed through a standard distribution manifold. Hot side pumping through zone valves to serve each zone. There are 7 zones served through a common pump and my indirect HWH having its own pump. With rough estimates I calculated my heat load on a cold day at 100,000 Btu/Hr. I have 114 feet of baseboard (using 600Btu/Hr industry avg rating @180 deg input) and a 36,000 Btu/Hr unit heater in the garage. I would like to leave the system as is with the following changes.

place a "T" fitting at both ends of the existing system supply and return. Connect my flat plate heat exchanger being supplied by the Garn to both "T" fittings creating a parallel system. The Garn through the heat exchanger on one side and the oil boiler on the other side. Using either an automatic (???? see below ????) or manual switchover (ball valves) to control which system would provide the heat. Obviously I would prefer an automatic system. My idea would be to install a zone valve in the Garn/Heat Exchanger side and also a zone valve in the Oil boiler side. By using an (as yet to be determined) aquastat relay with the Garn temp being the "If" part of the logic to control the closing of one valve while it opens the other and relays power to the boiler control. Basically isolating the oil boiler side from the Garn side of the loop. For example use 150F as the threshold for the relay to switch over to the oil boiler. I think with my baseboards and the heat exchanger setup, 150 out of the Garn may not be hot enough to deliver adequate heat to the house on a cold day. Any ideas on what controllers I would use? I need options and I want to stay as simple as possible on an automatic switchover. What controllers will work?????????

There are a couple of other ideas I would like you to let me know what you think. Would it be possible to de-pressurize the heat delivery side (baseboards etc) and hook the boiler side (under pressure) into the system with the heat exchanger. The water level in the Garn will be above the highest heat deliver unit with the exception of the garage unit heater. The boiler would definitely be more constant in its heat output and sizing a heat exchanger would be fairly simple. However, I'm not sure but I do know that corrosion is more of a problem on an open system. Also if I hook the Garn directly to the heat delivery system I would have copper and steel together and may have more corrosion problems. Appreciate your thoughts...

Another question... My indirect HWH right now has its own pump to facilitate flow through its coils, I'm assuming to give it kind of a priority for faster recovery. Would there be any advantage to separating the HWH and directly plumbing it into the Garn via unpressurized lines?

I don't know of a way to post a sketch of my proposed system. I tried to take a picture but it is grainy and hard to see in digital format. Any suggestions... I have an APPLE.

My apologies for being verbose. I'm hoping you all weigh in on this. I may not be able to respond in time to make this a "dialogue" type thread so let 'em fly.

 

[canyon]

Hopefully you will get some answers from the experienced ones here, but I have a few questions for you. Where in Alaska are you? Have you checked out some of the other Garn installations in AK or talked with them? If so, which ones?

 

[Nofossil]

Seems like if you install the HX as described with its own circulator so that it's connected in parallel with the oil, both drawing from the same reurn and both pumping to the same supply, you're in pretty good shape. Both oil and hx circs need to have check valves so that you don't get reverse flow when the other circ is operating.

In my 'simple pressurized system' sticky, I describe using a relay and an aquastat to disable the control input to a fossil boiler. I think that would work perfectly in your case and allow completely automatic changeover.

Hope this helps....

 

[Ice Cold]

will Zone valves work to isolate each leg (HX/Garn side from oil side), the taco golds literature say they can hold up to about 140 ft of head. If so they should work..??

Again One pump to send the heat out to zones. 15-42 existing in the oil system right now will hopefully just re-plumb and re-wire to come on when either oil or wood is supplying heat.

Do you have any suggestions on what aquastat/relay may work as I have described my proposed system above?

Are check valves needed in addition to the zone valves?

I can fax a diagram to anyone...... can't figure out how to use my APPLE to sketch a diagram.... any suggestions?

thanks

 

[Red Sun]

(broken link removed)

 

[pybyr]

red sun- I assume you mean that solarnetix has some offering to draw with- but in going to their web page, I didn't find it after looking around for several minutes- could you or someone else please point me where on their site to look? Thanks

 

[Nofossil]

I don't know what's out there for Apple, but I think there are a bunch of drawing related programs. I use Visio and Autocad LT for my drawings. A schematic is worth well over 1k words.

 

[Red Sun]

red sun- I assume you mean that solarnetix has some offering to draw with- but in going to their web page, I didn't find it after looking around for several minutes- could you or someone else please point me where on their site to look? Thanks

> The drawing is from Solarnetix only it was emailed to me. I have not seen it or any other drawings/schematics on their website, aside from illustrations of products. In the download section you'll find installation guides or manuals. However, they also provide software tools for design and planning. Although, the software is strictly a number cruncher and not a CAD system. It is for clean energy project analysis.

 

[Ice Cold]

Hey Nofossil I think I need to explain my plan a bit better. wish I could upload a drawing...

My plan is to use one pump for both parts of the parallel setup. Imagine the capital letter H.. the center horizontal in where the heat load and pump will be. the heat exchanger will connect the upper verticals and the oil boiler will connect the lower verticals. So in effect I will have two loops, one on the bottom and one on the top. DO YOU SUGGEST CHECK VALVES IN THESES LOOPS? each loop will have a zone valve, one will be open if the other is closed and one pump will circulate the water through one or the other loop depending on which zone valve is open. I'm still working on the control for these valves. My plan to isolate the oil boiler is to take the burner power supply lead from the boiler controller (honeywell L8124G) and run it through an aquastat on the garn with a cutout temp around 150F. For example during normal operation when a zone calls for heat the controller will turn everything on except the burner on the boiler will receive no power unless the cutout temp on the Garn's aquastat has been reached, when it is reached, the burner will receive power to ignite and heat the water using oil. Again everything will work except the burner until the cutout temp is reached, then the oil burner will fire. AM I CONSIDERING EVERYTHING? COULD THERE BE OTHER ISSUES I MAY NOT BE AWARE OF? Electricity can do funny things, and I don't want to burn anything up or try to do something really strange. CAN ANYONE SEE ANY PROBLEMS WITH ME "TRICKING" THE BURNER THROUGH THE AQUASTAT ON THE GARN? One thought is the load placed on the circuit, might it be too much?

This seems like a simple solution to get an automatic switchover but I'm looking for advice from you experts on this. I'm hoping you guys pick this apart and stimulate some thoughts and ideas or other solutions to this setup. I'm now trying to figure out how to control two zone valves and the circ pump from Garn to HX and back. One zone valve has to be open while the other one is closed. I'm thinking some type of relay maybe being fed through the aquastat that will be "tricking" the burner.

I am plumbing with 1-1/4" pipe from Garn to HX and back. During my rudimentary heat load analysis and using a 120,000Btu/hr heat loss and a 50 plate HX, in the future if we add onto the house I can up the flow using Nofossil's "tricking" the 3 speed pumps procedure to automatically switch from low flow to high flow, getting more heat out of the Garn. With the house as it is, 8GPM flow through a 24 plate HX would be enough. I would need 60-70 plate with 14 GPM for the 120,000 Btu's/hr. By the way, I used Flatplates online HX sizing program. I hope I entered and used it correctly.....

Again, apologies for my verbosity. Most likely more to follow.

 

[Ice Cold]

Canyon

the alaska distributor visited my house. He was in the neighborhood and stopped by. He is just getting started and told me they may get a contract to build them up here because of the high shipping costs. His name is dave and his website is alaskanheattechnologies.com. If you talk to him tell him Gordy said to give him a call. Great guy and if he doesn't know something he will admit it, and get an answer for you from HQ's engineers, may take a while but he is busy right now getting this thing off the ground. I haven't checked other installations but the simplicity of the Garn sold me. Initially decided on the Tarm but the heat storage costs would have made it more complicated and more expensive for me. Corrosion is something Garn takes seriously being an open system. they highly suggest participation in an annual water sample to keep tabs on the system. It is the only down side to the Garn as far as I can see. I'm in Willow, PM me and we can correspond. By the way Dave will be at the state fair with a unit.

 

[Nofossil]

Ice, one problem might be that zone valves typically have a very restrictive orifice, This is so that if you have several zone valves in parallel, the flow will end up getting divided fairly evenly among them. I think you might have some trouble getting enough flow throuh a zone valve to supply your whole system.

Circulators are about the same price as zone valves. I'd suggest using a 'one circulator per heat source' approach. That way, you can size each circulator to match the heat source. In that scenario, I'd use an aquastat on the Garn to disable the demand signal to your fossil boiler. Disabling the burner might cause the fossil controller to throw a fit.

 

[Ice Cold]

I don't know much about the internal parts of the zone valves. I was considering using taco 573 1-1/4 valves to get the cleanest flow through as I can. DOES ANYONE KNOW OF OTHER VALVES AVAILABLE IN THE 1-1/4" RANGE???

I'm also wondering if I use circs instead of valves, will one circ that is not operating stop the flow through itself completely as the valve would. This is one of the biggest benefits of a parallel system, no lost heat circulating through the oil boiler and being extracted by the draft and sucked up and outside. I don't know if check valve pumps will work because they will be situated the same direction. In other words, I am wondering if one pump will still force water through the non operating pump because the check valve is in the same direction as the flow.

If I disable the demand signal, the pumps won't come on..... I need to think about this some more. stand by