My water coils HVAC plumbing

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PapaRazzzzee

Plumbing newbie
Joined
Mar 26, 2015
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Location
, Quebec, Canada
Hello,

I'm planning and designing my next house. In this house i absolutely want a central HVAC that is warmed and cooled by water coils and a blower, and i want to completely build it by my self. Since i'm a newbie in plumbing, i made some researches on the internet about plumbing, and a lot more on HVACs. I designed a first diagram on my HVAC and plumbing, and would like to have plumbing advice from experienced plumbers on: What is missing? What did i do wrong? What could be improved? So i could go deeper in my designing and planning.

Thanks for your cooperation!

My HVAC diagram.jpg
 
Hi Frodo,

Thanks for the diagrams. I see in the first diagram you are giving advice on the coils order but on your drawing it's the exact opposite of your advice! I'm pretty sure the order is: "Air entry --> Filter --> Cold water coil --> Hot water coil --> And finally the blower". Anyways, for now i want to concentrate on the plumbing side, the HVAC unit details will be later.

On your second diagram, i found the valves that were missing on my diagram. I see that you put the pump at the tank drain fitting. I found some diagrams on the internet for recirculating loops that had the return line connect back to the supply line. Maybe this is not a good idea, after all, you're the expert, but can it be done this way?

And finally on your third diagram, i'm not sure what the 3-way valve is doing there with the "thermostat-controlled" thing? My thermostat/humidistat controller will only trigger the hot and cold water pumps, and the HVAC blower. Maybe there is something i don't understand with this diagram, could you be a little bit more verbose please?

Finally i drew another flow diagram and added the valves as much as i could understand your diagrams. I also simplified the view of it and changed a few things on the cold side. Your advice would be much appreciated.

Thanks.

My HVAC diagram 2.jpg
 
no, it is not the exact oppisite...it is fan, filter, hot water coil , cold water coil

what i was talking about was the supply and return openings on the coil itself.

the reason you want your filter before the coil, is to keep the coil clean.

if you put it after the coil, dirt will plug the fins.

so, either before coil or...in your return air plenum

images (3).jpg

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3 way valve. you have a circulating system. so that you can get heat when you want heat, not 5 minutes later,

the 3 way valve allows the water to circ when the stat is satisified. the water stays hot..when the stat calls for heat/cool

the bypass closes off , the water goes thru the coil the fan kicks on..your all cofmy and smiling

if you did not circ your system, you would have to wait for it all to come on and heat up

usually...you can get away with a 3 way at the end of a run, [the fartherest coil

and the ones inbetween get 2 way valves

images (3).jpg
 
Thanks Frodo,

Now i understand better the purpose of the 3-way valves triggered by thermostats. This way i beleive it would be best now that i'm thinking of adding a second HVAC unit in my garage (woodworking shop). I'll redraw using your advices. About the thermostat/humidistat controlers, i'd like to make sure that there are some programmable out there that i can trigger the 3-way valves in many ways, like hot only, cold only, or both when i want to dehumidify in cold temperatures, and that it will always trigger the fan in any of those cases. It would also be perfect if that controler would be able to shut off the recirculating pumps individually if lets say their respective 3-way valve had not let hot or cold water go through for lets say one hour (or programmable periods), because in the summer the hot one will most likely not work and the same for the cold one during the winter. This way i could save on energy costs. Would you have any controllers like this to suggest?

About your last diagram, i don't understand the Hot Water Overflow tank on the Cold Water line?

Sorry if i'm giving you a hard time, in case you didn't notice i'm new to plumbing!!! lol :)

Thanks again.
 
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Hi Frodo,

Thank you again for all the great information you gave me.

To answer your question, i intend to keep my heating water between 135-150 F.

Now i gathered all the information you gave me, as much as i could, and came up with a new diagram for the hot water portion only(i could not read your last diagram cause it's too small). I will do the cool portion later on, maybe when we're done with the hot portion. I added the 2nd HVAC to it. Keep in mind that both HVACs are going to be controlled seperately, each with their respective thermostat. Does my plumbing logic look better on the new diagram? Anything i have wrong or forgotten?

And by the way, i Googled "pt ports" and "pets plug" and did not find anything meaningful. I put them on the diagram anyways. Looking into this glossary, what would they call it?: http://www.prismflow.com/glossary.html

Thanks.

Regards.

My HVAC diagram 2D.jpg
 
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Hi Frodo,

I updated the hot loop diagram.

I also built the chilled loop diagram. Any missing valves or unappropriate setup?

Thanks!

2D Hot water loop.jpg

2D Chilled water loop.jpg
 

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