hydronic heat for the barn - part 15

One of the reasons I built the shelf adjacent to the boiler is to create a simple way to mount the eight gang switch bank assembly for the hydronic actuators. I was planning on simply mount the switch bank on the underside of the shelving.

one easiest way to is to mount the switch bank under the shelf with two small L brackets

However seeing how nice the shelf turns out I don't want to ruin its aesthetics in doing so. Instead I racked my brain to find another simple way to mount the bank. My goal is use what I have and not spend a penny.

At the mean time while waiting for the actuators to arrive via slow boat from China I round up the material that I will need to wire up the actuators which including a larger 24V AC transformer, and a way to power the LED illuminators inside the switches. They need between 5V and 12V DC. Again I want to use what I already have.

I found this 24Vac transformer in my junk pile 

each actuator is rated at 2 watts so this transformer comfortably can handle eight

for the DC needed to supply the LEDs I cannot find my LM7805 voltage regulator so I try to see if I can use this DC motor controller instead. I wired up a simple half wave rectifier off the center tap of the transformer giving me nominal 12Vac before he rectifier.

The problem with rectifying AC into DC is you ending up with the peak voltage so for a 12Vac you end up with 12V/0.707 = 16.9V. The DC motor controller has a 555 timer and per spec the Vin max is only 15V. I risk destroying the controller module, so I scrap that idea.

I could not find any simpler way to mount the switch bank, except fabricating some long standoffs. I made them out of filament wound compost rod. 

I plan to mount the switch bank above the return manifold

The beauty of the switch bank controlling the on/off of the loops is I can re-map the ordering of the loops in a sequence that is easier to remember. 

I resume reacting more plywood wall panels

the last piece of with each bay wall need to be trimmed as well as notched for the anchor bolts and the MC cables

I gotten quite good in notching the bottom corners

pulling up the vapor barrier one last time to add EPS foam to protect the mini split lines and the MC cable from being punctured by the self-drilling fastener used to fasten the plywood

I got the back walls of three bays done and now the barn looks like the boarded up businesses in Portland downtown

From the time of order to the delivery of these actuators it took 25 days from China. 

there are multiple shipping entities involved in the international shipping

note the vendor peeled off the product label, which I suspect they are in fact branded for the like of Sharkbite or Uponor; I will have two spares

IP54 is an ISO water resistant standard

I immediately put one to the bench test using the 24Vac transformer

I only realized it is a thermal wax motor seeing the delay of movement of the piston. It is really an elegant and cost effective design. One thing that I wonder is if the return temperature is high can it affect the on/off switching of the actuator.

the one on the right has been energized

at steady state each draws about 0.20A; however I suspect the clamp meter reading is too high due to the stray magnetism of the transformer

Per spec the power consumption is 2 watts. That works out to only 83mA per actuator and 0.67A if all eight are energized.

still I wasn't committing to installing them until I test a couple on the return manifold

the in-situ bench test was a success

The characteristics of these actuators are the actuation takes about 30 seconds from the time it is at room temperature to being heated to fully activated. Once they are activated, it takes a few minutes to de-activate as the entire mass need to dissipate the heat. But they work reliably and should be quite durable. The slow de-activation time is not a problem in the time scheme of in floor heat. I chose normally open type so they only are energized when I want to switch off that loop.

I want to fit the transformer together with a switch for it inside this duplex outlet box except one screw lands on a knockout that wants to break off so I apply couple of weld spots to secure it

everything fits nicely in this duplex box; the switch allows me to switch off the enabled actuators when I switch off the radiant heat for the night via the thermostat to conserve energy

the need to joint 8 pigtails conductors to 28Vac common is handled with a 8-place terminal block

I demonstrate two actuators closing the loops

I would had tidy up the actuator cables more if it were not that the aluminum wires are so brittle at the crimp lugs

Finding these elegantly design manifolds in conjunction to the actuators really make the radiant floor heat shine. This turned the uncontrolled 8 loops into 8 zones with the incremental cost of under $100 with a few hours of work while keeping the system complexity down to minimum. The only things I bought to add the actuators are the actuators and the 8-gang switch bank. All the rest are material I already have at home. I would tease my track buddy who previously owned a hardware store that I have more parts selections in my stash than his store.

with the two loops I normally want on the boiler runs at 10% BTU capacity at steady state target temperature of the thermostat; of course many factors influence the BTU rate

I spent countless hours observing how the smart thermostat interact with the smart boiler. There are a lot of subtleties and one only see them by observing with attention to details and knowing how their respective control algorithms were designed to function. I am very impressed with the adaptive algorithm of the thermostat and the ability to customize the temperature control.

The only thing that I wish it has is built in wifi remote support for my unique use case. Most people will simply set the weekly or daily schedule and leave it on auto-pilot. I want to control the hydronic system like plumbing in a submarine.

Good designs always strive to be simple in the result. All too often people confuse complexity with good design. Complexity typically result from lack of design refinements, or simply poorly conceived wishlist functions. 

the Happy Kitty shrine is now a cozy place to hang out with friends and neighbors

My good neighbor family here has been over to hang out in the barn whenever they come to their cottage from Portland for the weekend.

Doubting the original current measurement being inaccurate, I went and measure it again this time not near the transformer. the current is just 5 mA. At this low level I would just say it is in the factors of teens or tenths of mA as it is at the sensitivity of the meter. Engineers will say it is in the mud.

a close up of the terminal strip I used for the common signal

the documentation for the actuator is poor at best and it seems to suggest once the operation temperature is reached it self regulates to maintain a target range