Upgrading to an Air Source Heat Pump: Chris’s Journey

An air source heat pump is a magical invention. It’s a far more efficient way to get your hot tub to the right temperature. In my own case, it saved me as much as 60% in energy costs. Given the right circumstances, it can be a rewarding investment. 

Installing an air source heat pump could be confusing, but I am here to help you out with a step-by-step guide.

Here’s a recent example of one of my clients, Chris, who connected with me via email, and we went through the process of installing an air source heat pump together with a few interesting discoveries along the way.

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Chris’s Introduction

 

Chris emailed me and said he wanted to upgrade his electric heater to an air-source heat pump. As with all my clients, I was more than happy to guide him through the installation.

 

The first thing I need are pictures of the existing setup and the internal parts, like the one Chris sent in. Once reviewed, I can tell you everything required to complete this project.

Having decided that he could in fact do this upgrade himself, armed with my plans and instructions, Chris ordered the Air source heat pump and a connecting kit from my website. Once they arrived, he got started.

 

Note: Be careful when selecting a connecting kit because many options exist for different circumstances and models. Feel free to contact me, and I’ll help you choose the right one. 

 

Chris’s Setup

 

Chris’s existing setup includes a circulation pump and a jet pump. Our focus is the pump currently connected to your electric heater, where we will connect the Air source heat pump. 

The first thing we do is mark the setup. Here, I’ve marked three pipes. The purple shows where you need to cut the pipe. The blue shows the cold input, and the red shows the hot water return from the heat pump. 

I also sent a diagram that looks similar to the one below. This diagram matches your layout and describes the steps to install the air source heat pump.  

 

Installing The Air Source Heat Pump

 

Once Chris’s order was delivered, he began working on it. A few days later, he emailed me the following picture, wondering whether it could be helpful.

This was surprising because I’ve done hundreds of air source heat pump installations and have never seen a pre-plumbed bypass on a hot tub. Granted, newer hot tubs already have this setup in place, making it easier to add the air source pump when you decide to.

 

After this discovery, adding the air source heat pump was so much easier. Chris didn’t need to cut any pipes. All he had to do was plumb into this bypass. Once the pipes are in, you close the bypass and open the inside, and the water is ready to go to the air source heat pump. 

 

Don’t worry if you have an older model without a pre-included bypass. You can use your connecting kit to cut in a new one. 

 

After a few usual emails regarding the installation and setup process, the emails stopped, and I thought that was another successful air source heat pump installation. 

 

“I’ve got a problem…”

 

A few days later, I received an email from Chris saying he had a problem with his water flow. He was getting an E3 error on his control panel, which means that not enough flow was going through to the heat pump. 

 

This is usually caused by an airlock that can be created during installation. To clear the airlock, open the system’s highest part and let some air out. However, in this case, water was coming out, meaning there was no air trapped in the system.

 

We were sure this had something to do with the heat pump and an airlock in the pipes and tried many different ways to fix it. One thing to note was that the heat pump would work when he turned the jets on but would turn off again when he shut them off, which was strange. 

 

Eventually, we figured out that it wasn’t the bypass; it was because the hot tub’s temperature was not set high enough. 

 

To understand this, you need to first understand how an air-source heat pump works. We are actually controlling the air-source heat pump indirectly via the flow of water, which means we need the circulation pump to physically turn on to send the water to the heat pump. 

 

You must set the hot tub temperature to high to turn on the circulation pump. When it calls for heat, the circulation pump turns on and pumps water to the air pump, turning it on. 

 

In the winter, we match the temperature with the air source and the hot tub, so we lower it on both because it’s more costly in the colder season. 

 

End Result

 

Chris had no leaks and a newly installed air source heat pump. The entire setup looks great, and he’s now got a hot tub that heats up quicker and is also a lot cheaper to run. 

 

Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi