Outdoor reset

[nate379]

Started to put an outdoor reset on the boiler today.

First it started with replacing the zone controller, Taco 404 to a Taco 404EXP. I would have figured it would be a simple swap, but there were a few things different between the two and it took some figuring out.

My setup has 4 zone valves and 2 pumps, and also another controller that controls a pump for DHW.


Go to install the Taco 700 outdoor reset
(broken link removed to http://www.taco-hvac.com/en/products/PC700+Boiler+Reset+Control/products.html?current_category=150)

and I'm not sure what Taco was thinking but what the heck. All the zone/pump controllers they sell are surface mount. Well all of a sudden this outdoor rest is setup to be mounted over an electrical box. Why the hell would someone mount this to an electrical box in the wall but have the wiring come out through the wall to hook into the surface mounted zone controller? haha!

The the pre-wired hookups that go into the zone control box is like 12" long, so you can mount the outdoor reset almost no where.

Nothing is ever easy is it?

 

[Don2222]

Hi Nate

Is there any reason you choose the Taco Outdoor reset?

My boiler analyst always uses the Tekmar 260 with a Honeywell LZ2480 1006 Aquastat.

There are many reasons for this.
The Honeywell Control has the Hi Limit switch and can control the boiler until the Tekmar 260 is hooked up.
Also if the Tekmar fails but the Tekmar is rated one of the best!

The Tekmar 260 will work with either Zone Valves or Circulator Pumps (Any brand) However to take full advantage of all the energy saving features Circulator Pumps for all Zones including the Indirect zone works best.

http://www.tekmarcontrols.com/hvacsystems/260.html

Also more people use this control so getting help may be a tad easier.

Sorry I cannot help you specifically with your Taco Outdoor reset but I can help with general questions such as:

The Outdoor sensor should be mounted on the North side of the house for best performance.
The Indirect Water tank should have a heat loop in the Hot Output to prevent loss of heat during the night and other non use periods
Also a DHW expansion tank is recommended on the cold line into the tank so when the Indirect Tank Water is heated and expands it pushes the cold water out into the expansion tank keeping all the hot water in the tank!!
The DHW Expansion Tank pressure must be adjusted to match the water pressure in the house in PSI !!

Good Luck!!

Pic of heat loop (12" x 12" x 12" Copper) and DHW expansion tank (Adjustable from 20 - 80 PSI) from Home Depot ($35.00) below:

 

[nate379]

Tekmar makes the controllers for Taco. I am using a Taco one cause everything else in my system is Taco. The outdoor reset just plugs into the EXP zone valve controller.

Putting sensor under eve on corner of north and west wall. Not as "ideal" but I have had a temp sensor there for a couple years and it reads correct to temp other than. 18" overhang so it's shielded well from sun and rain.