How to Replace a Hot Tub Blower (Check Valve and Hartford Loop Included)

Last updated: September 2026

Nothing spoils a relaxing evening like finding your hot tub blower has stopped. If the jets are quiet and the bubbles have vanished, don’t panic. In many cases, replacing a blower is a manageable DIY job, as long as you do it safely.

Before you grab your tools, here’s the most important rule of hot tub maintenance.

Electricity and water do not mix

It’s essential that no water enters your hot tub air blower. If water reaches the blower’s internal parts it can trip your breaker, or lead to worse electrical hazards. Read water in a hot tub air blower if you suspect that’s what has happened.

Before you begin any work:

• Disconnect the power at the breaker.
• Unplug the electrical components and make sure nothing is live.
• Only carry on if you’re confident handling electrical equipment. If not, get an electrician in.

Why blowers fail: the check valve and Hartford loop

The usual reason a blower dies is water running back down the air line into it when the blower is off. The cure has two parts, and I’d fit both:

• A check valve in the air line, which lets air through one way and stops water coming back.
• A Hartford loop, where the air pipe rises in a loop above the water level before it drops to the blower, so water can’t siphon or creep back down to the blower.

A blower that gets water in it will often trip the breaker or fail soon after. If you’re building a tub, my guide to wiring a blower and the ultimate guide to the hot tub air blower show the layout, and air blower or venturi helps you choose.

How to replace a hot tub blower

1. Locate the blower

Finding the blower can take a moment, and it varies by model. It’s typically near the pump. It’s smaller than the pump, and unlike the round filter it’s compact and tucked into the equipment bay.

You’ll probably also see a check valve near it, which stops water flowing back into the blower.

2. Disconnect the air lines

Once you’ve found the blower:

• Remove the air lines. They’re usually held with jubilee clips (hose clamps) or threaded connectors.
• Keep the connections to reuse.

3. Disconnect the power from the spa pack

• Open the spa pack (the control unit that powers the blower, pumps and heater).
• Double-check the power is fully off at the breaker.
• Find the blower connector, often an AMP plug or clip, and disconnect it carefully.

The blower can then come out. If you need to find out where things plug in, see the spa pack guide.

4. Check the blower specifications

Before buying a replacement, read the label and power rating on the old blower. The new one has to match the voltage (120V or 240V in the USA, where supply is 240V split phase, or 230V in the UK) and the power (for example 900W or 1 to 2 HP), and it has to suit the output on your spa pack. See hot tub wiring explained.

Installing the new blower

Now reverse the process:

• Connect the new blower to the spa pack with the right electrical connector.
• Close the spa pack carefully, making sure no cables are pinched.
• Reattach the air lines with the same clips or fittings.
• Check the check valve is secure and the right way round, and that the Hartford loop is above the waterline.

Power on and test

1. Turn the power back on at the breaker.
2. Wake the tub from the topside control.
3. Turn on the jets, then the air blower.
4. Let it run for a few minutes and watch for leaks or faults.

If all goes well, you’re back in action. If the blower runs but you get no bubbles, or if it is controlled by an air button that no longer responds, see how to change an air button and latching relay.

Common mistakes

• No check valve or Hartford loop, so the blower fills with water again.
• A replacement of the wrong voltage.
• Working on the blower without isolating the breaker.
• Pinched wires when closing the spa pack.

Need a new blower?

You can browse air blowers on parts4tubs.com (USA) or find UK stock at parts4tubs.co.uk.

Replacing a blower is a cost-effective alternative to calling a technician, and it’s a great way to get to know your tub. Safety first, and if you’re unsure at any point, consult a professional. Thanks for reading, and happy hot tubbin’! If you’re new here, check my other posts and my YouTube channel.

FAQs

Why did my hot tub blower stop working?

Common causes are water in the blower, a blown fuse or relay in the spa pack, a failed air button or a burnt-out motor. Check for water first.

What is a Hartford loop on a hot tub blower?

A loop in the air pipe that rises above the water level before it reaches the blower, so water can’t run back down into the blower.

Do I need a check valve on a hot tub blower?

Yes. It stops water flowing back into the blower through the air line. Fit it together with a Hartford loop.

Can I replace a hot tub blower myself?

Yes, if you isolate the power and are comfortable with the connections. Match the voltage and power of the old blower.

Why does my blower trip the breaker?

Usually water has got into the motor. Dry it out as in the guide on water in blowers, and if it still trips, replace it.

Got a question about your own setup? Drop it in the comments below. I read them all.

Cheers,
Andi

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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.

Fast forward to 2025, I've helped over 1400+ 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