Heat Pump Line-sets

October 26, 2022

With winter coming soon, I’ve been focusing my attention on getting the heat pump working. First I ran the power from the building to the outside unit.

The line-set and communication wire will also need to be connected through the other holes.

Adam came over to help me run the line-set, and we spent some time planning things out. Due to limited access to the inside of the wall, I decided to run it up the wall about 13 ft before passing it through the wall into the attic. However, After some careful measuring, it became clear that the line-set I purchased was too short. I ordered a longer line-set, and listed the shorter one for sale, hoping to recoup most of what I paid.

The 25 ft. line-set was only about 2 to 3 ft. short, but the next size up is 10 ft. longer.

Meanwhile I also realized I should have painted the line-set cover before attaching it to the building. I painted the parts that weren’t yet attached in the studio.

Painting plastic is always a challenge, as it can take up to a month for the paint to fully adhere.

Then I masked off the already attached parts and painted them in place.

Thankfully I have found a readily available spray paint that is nearly identical in color to the siding.

Then I ran the line-set from the attic out to the outdoor unit.

I placed a flexible cutting mat from our kitchen around the line-set to ensure it could slide through the hole without getting caught on the sharp steel siding.

Unfortunately, one of the adapters had a small leak, so I just disconnected it and set it aside to fuss with later.

It turned out the leaking adapter had a defect in it, and I’m working to get a replacement from the manufacturer.

Next was the task of bending the line-set to fit inside the line-set cover.

Bending the stiff 3/4 in. line was especially challenging to do from atop a ladder.

This proved very difficult since the area at the top which I needed to bend just right could only be accessed with a ladder or by reaching over equipment in the attic.

My arms were sore afterward from pushing and pulling so hard and in such awkward positions.

I got it pretty close, and started covering the line-set. However, it quickly became apparent that the line-set barely fit inside, and there was no way I would be able to bend it tight enough to get it to fit at the top.

The new line-set cover is 6 in. wide and 4 in. deep, allowing everything to fit comfortably compared to the 4 in. wide and 2 in. deep cover that I tried to make work.

I took a break, ordered a different line-set cover with plenty of room, and moved on to the electrical.

Because I ran 10/3, I ended up with an unused neutral wire.

I wired up the 220v power and the 24v communication wires.

I ended up cutting the hole the lines pass through downward and bending the siding in a bit, such that the line-sets rest along a smooth flat surface, rather than a sharp edge.

I then ran the communication wire to the attic inside a waterproof flexible conduit, which will then be concealed in the line-set cover.

The connections to the indoor unit are very tight, requiring us to remove some of the insulation from ends of the lines. I’ll have to add some other, less space-consuming insulation to avoid condensation.

Adam came over again a few days later to help get the line-sets connected.

Adam used some compressor oil on the connectors to help ensure a quality seal.

We swapped out the leaking connector with an identical one from the not-yet-sold 25ft line-set kit. Now both lines are connected without leaks.