Atmos my schematic shoot her full of holes please

[benmaupin]

Gentlemen, Here is the close to final plan on the Atmos DC50 install with proposed schematic. I intend to control all with TECKMAR controls...specifically 157 with add ons to have outdoor reset etc. The concept is pretty simple, max burn with heat going to storage and heat zones (all radiant floor) being able to pull when bolier is running and off the storage when boiler is spent. The backup system will be manually switched out of the system until vacation/away time where I'll burn heavy and then switch on the back up to control the heat.
I am still matching up the control schematic and will post when finished. sorry for the bad graphics but ya gotta live with what you get when editing and switching between microsoft power point and basic paint. I am to cheap to buy software and want to leave a complete schematic with the system in case I kick off beofre the wife.
I will be doing the install my self.

 

[Nofossil]

Couple of comments:

1) Why not put the Argos circ outlet directly into the Argos? That way, it wouldn't have any tendency to push water through the Atmos.

2) When the boiler(s) are flowing more than the zones need, there are two paths to storage: one direct and one through the sidearm. Easiest would be to have one path, and typically the temperature drop through a sidearm isn't enough to render the exiting water 'cold'.

From a control logic and flow point of view, this is essentially the 'simplest pressurized storage' approach. The sticky describes an approach to implementing control logic if that would help.

 

[DaveBP]

Looks like the backup boiler might be sending some of its heat to the storage and DHW tank, depending on pipe resistance and how the circulators are cooperating. Except for freeze protection in the winter I'm not sure that is your intent.

 

[Nofossil]

Looks like the backup boiler might be sending some of its heat to the storage and DHW tank, depending on pipe resistance and how the circulators are cooperating. Except for freeze protection in the winter I'm not sure that is your intent.

Good catch. I think swapping the position of the storage and backup would solve that problem, although it might increase the risk of the load circ pulling water through the backup when you really want it drawing through storage.

 

[WoodNotOil]

I agree with Nofo to put the Argos pump after the T so flow is only to the Argos.

Looks like the backup boiler might be sending some of its heat to the storage and DHW tank, depending on pipe resistance and how the circulators are cooperating. Except for freeze protection in the winter I'm not sure that is your intent.

Good catch. I think swapping the position of the storage and backup would solve that problem, although it might increase the risk of the load circ pulling water through the backup when you really want it drawing through storage.

I think a better solution to this problem might be to T in the zone returns on the line between the storage and the Argos. That way it wouldn't return through storage when either boiler is running, but would when storage is in use. Just a thought...

 

[in hot water]

How will you control the supply temperature to the radiant zones? Will it get whatever the boiler can provide, say 180F or more? That may be a bit too hot for the floors. You might want to include a mixing device.

You really don't want, or need the backup boiler to flow through the Atmos or storage, they both will pull energy $$s from you wallet.

One properly placed expansion tank would be better.

 

[benmaupin]

All...
Thanks for the input. I'll answer all in this one post.
I will switch the back up and the storage as the back up need not heat storage.
The side arm will be fine I think as everything flows back to storage with no real loss even if it takes priority.
Lastly the supply is temp controlled by electrical mixing valves based on setbacks/demands etc... there is piping missing on the drawing in that area for colder return water for the mixing. As I have radiant flooring I can't use the 170-180 degree water.
Lastly I will put the Argos circulator in the line under the argos so it is effectively bypassed when not in use.
I'll post another with the changes and the controller schematics matched.

Ben