hydronic heat for the barn - part 13

Up till now the hydronic system had been test-fired for basic operational checks. Next I installed the thermostat and the outdoor ambient sensor. The outdoor sensor is used by the boiler controller to regulate the boiler temperature as well as the exhaust gas temperature for the highest efficiency as a condensing boiler.

the ballooning hose on the feeder supply side

I use a single ear pinch clamp to fix the leak but the hose now balloon from the circa 60 PSI pressure. It is very concerning as I worry it can rupture any time. Something has to be done and I made sure the boiler is switcher off and gas supply also off at the end of the day.

I mounted the outdoor temperature sensor in the valley of the siding

The algorithm used for outdoor temperature compensation is called Outdoor Reset, which is the most stupid name some bureaucrats can come up with. It is on all high efficiency modern boiler like this. There are four parameters that one programs into the boiler based on the location seasonal temperature and desired boiler water temperatures range.

The thermostat is designed to be surface mounted with the wires fed through a hole into the wall. I didn't want to go through the pain of feeding and fishing for the wires behind the plywood panel so I figured out a way to surface mount it. I saved this wine box that just keeps on giving to the barn project. I used it to mount the garage door opener controls and now this. I routed a channel for the wires on this piece of wood adapter.

24Vac, thermostat out, and slab sensor

I have been keeping an eye on the propane level to gauge the consumption; the needle had not move in any perceptible amount

I discovered this plastic thing does not belong to the top of the burner/heat exchanger. It must had fellen off from the metal bracket at the back of the enclosure. The heat had deformed the plastic case but no harm is done to its function - it is the high voltage spark ignition transformer.

I didn't like the makeshift system feeder water jug

while waiting to buy the translucent water jug next time I go into Portland I found this cat litter container I saved; it makes a great temporary stand-in though the wall is a bit thin

during all this time the pump has been emitting an unpleasant odor, but it is just the paint exposing to high temperature for the first time since made

My cheap 8-gang SPST switch arrived from Amazon so I put it to the tests. I wanted to see the built in LED illumination. It turned out at the intended 12Vdc they are obnoxiously bright. To make them livable I lowered the supply to 3Vdc. As the switches will be switching 24Vac, I will add a rectifying diode and a (or two) zener diode to drop the LED voltage to around 3Vdc for the LEDs.

3Vdc is the lowest before some LEDs stop illuminating

I got around to fix the plumb side hose that threaten to rupture by scrounging for all the parts to my disposal without taking a trip into town

I stole this braided hose from the utility sink

 

fixed

Next I set out to adjust the burner combustion flame. They repeatedly warn that all installations have this carried out with a combustion gas analyzer. I am one that never follow the stern warnings when I see fit, and in this case I will not a thousand dollars to buy one to use it once. I paid attention in high school chemistry class on the invention of operation of the Bunson Burner. If my eyeballs say it good, it is good enough for me.

do what I say but don't do what I do

the adjustment is done at the lowest fire setting (10% capacity) but check at both low and high fire (100% capacity). No matter what I did the flame tends to be quite orange at low fire even when leaned out. If I set it more blue the ignition will fail or unreliable. Hence I set it just slightly richer than when the ignition became unreliable. The flame is always very blue at high fire (100%) as well as in the teens percentage. I called it accomplished. For all I know the next batch of propane may tell me otherwise.

rather than filing a warranty claim for a replacement I use a cable tie to secure the ignition transformer to its bracket

I decided to set the dip switch for the 2" or 3" air intake and exhaust pipe size to 3" even though my installation is 2"; the reason should be very obvious; another instance that I don't do what I am told

One thing that really tripped me up about American thermostats is they tend to be designed for archaic central heating system. Even this modern one for heat only with floor sensor. There is no dry contact outputs and they don't explain what the output characteristics are. I would came to conclusion it is intended to drive a archaic 24Vac relay in the heating equipment. But this boiler has no such thing built in. My junk pile of electronics came to the rescue again. I have a used 24Vac relay with exposed terminals. I quickly wire it up for use inside the boiler.

I needed to figure out an easy way to prevent the exposed contacts from shorting to the metal cabinet

a Trader Joe's cheese container was improvised

next I build a nice shelf for the feeder reservoir with two Ikea shelf supports

I finally install the lower trim panels for the mini split IDUs

I also made the rodent grill for the air intake pipe out of some rusty chicken wire

I cleaned up the temporary plywood shims that I used to train the stiff PEX pipes

a quick dish inspired by the Fujianese dish named "Buddha Jumps Over the Wall" 

with the warm copper pipes behave like a radiator I had the idea of putting the sleek clothes hanger that I bought back from Hong Kong to work

it is intended to be flush-mounted with the hanger arm concealed when not in use

I add pipe insulation to the condensate drain hose to deter the liquid from freezing; I suspect it cannot prevent freezing in extreme cold and windy condition

the boiler has excellent realtime system operational parameters but I want to monitor the temperatures of supply, floor return, and primary loop bypass return

during operation the system is quite quiet

as the cat litter container cum feeder reservoir grew on me I made the shelf to tailer fit and also with space for the test equipment

I found a not too bad location for the floor sensor without drilling a hole

I monitored the system in operation for days. I am extremely impressed and the outcome exceeds my expectations. Once reached set point the thermostat adaptive algorithm will cycle calling for heat even when the target and actual temperature are the same in fahrenheit. The boiler too will cycle the burners on/off based on the water temperature in addition to the ability to down modulate to 10% if needed. I captured the moment when it modulated down to 10% in the following sequence of photos.

fan speed at just 1380 RPM

the burner flame is quite blue

modulated BTU/hr at 10%

With only two loops opened it typically has been operating at 16% capacity. I seen it as low as 10%. My aim is to minimize the propane consumption and only use the hydronic heat to keep the feet comfortable during the coldest period of winter. The performance of the LG mini split exceeds my expectation in comfort, quietness, and energy efficiency. The barn has the internal volume equivalent to a house of over 8,000 square feet due to the ceiling height.

I am glad I chose this Laars FT199 heat only boiler. I only discovered it on Youtube while my initial choice was one made by Peerless as one I had in the previous house. Of similar capacity Peerless is nearly 3 times the cost of this Laars. I have complete confidence with a boiler designed and made in S Korea and I am impressed to say the least.

Combi boilers are very popular now for hydronic heat where you also get domestic hot water from the same boiler. However with my experience I prefer to keep them separate. I prefer dedicated boilers for the task and a combi has too much compromises for my liking. The biggest being the long route to my wet service points. At this point, I can say this boiler is an ideal choice for my needs.