Solve Your Onix Tubing Problems Easily!

While Onix is a great brand for heating solutions, they can be problematic sometimes. If you notice any heating system issues, chances are tubing is the culprit. However, your boiler issue can be solved easily with some proven methods.

So, how to solve your Onix tubing problems?

You can start by using the proper-sized Onix tubing and cleaning the tube. Another solution is to go for high-pressure pumps. Your low-pressure pump can cause water flow or boiler issues. However, all of these issues need proper inspection before you can implement the solutions.

This is just a glimpse of solving tubing problems. In this content, we’ve explained each of them, and how to overcome those-     

Onix Tubing: 2 Major Problems!

Tubes are a significant part of a boiler. When a tube has issues, the whole functionality of a boiler collapses. If you’re an Onix user, you’re not the only one who’s suffering-

Anyways, here goes the problems and their solutions-

Problem 1: Slow Water Flow

Have you ever had water flow problems in a boiler? Sometimes, you won’t get the water flow as you expected. It’s as slow as a turtle. Absolutely frustrating!

Onix radiant tubing


Now, there are a few reasons this problem might arise-

  • You might have chosen the wrong sized Onix tubing.
  • There might be a defect in the piping.
  • The tube might get clogged up. 
  • Having a low-pressure pump

So, what’s the solution to this? I’ll tell you in a bit. Stay with me!

Solution 1: Correct-Sized Tubing and Fixation

First of all, you have to choose the correct sized Onix tubing. Then, you must fix any issue in the pipe. Make sure it doesn’t have any leaks.

Correct-Sized Tubing and Fixation

If fixing a defect seems tough to do, call a technician to help you in this case.

Solution 2: Cleansing the Tube

Often, slow water flow through the tube happens because of a clogged-up tube. Because of dirt getting clogged up, there remains less space for water flow. As a result, the water flow gets slowed down.

So, what do you have to do in this case? You guessed it right. Clean the clogs!

Here’s a step-by-step guideline on how to clean Onix tubes:

  • First, you have to shut down the boiler. 
  • Then, start blowing it down. Keep the pressure on while you do it.
  • Now, activate the drain and flush the unit.
  • At the same time, you have to close the steam valve.
  • After that, you need to add a descaler and top it off with water.
  • In the next step, circulate the water from a low point or drain. Bring back the high point of the boiler to a vented container. 
  • Do this for 4-8 hours depending on the volume. 
  • Then, open the steam valve.
  • Lastly, you have to drain and flush consecutively. After that, refill the boiler and hit the start button. 

Solution 3: High-Pressure Pump

The circulation pump you’re using can be responsible for the water flow. If you’re using a low-pressure pump, it’s obvious to get into this problem.

However, you have to detect the problem first.

First, check the circulation pump if the water flow is circulating correctly. If you see water flowing through all the loops associated, you’ll understand it’s a good sign. 

Remember you have to ensure the water is coming out from the hose connection.

Then, fill the tank and purge it. If the pump is not working, this means there’s an air lock inside. That’s when you understand you need to get the pump changed. 

So, that’s why you must use a high-pressure pump. 

In case you need to replace the high-pressure pumps, here are some of the pumps you can switch to-

Let’s move on to the next problem regarding cold baseboards.

Problem 2: Cold Baseboards

Now, radiators can take time to heat up. But sometimes there’s no heat at all. You’ll notice that the baseboards didn’t even get warm. Let alone the whole room! 

Reasons behind this? Here you go-

Reason: Year-Old Baseboard left Unmaintained

You might have installed a baseboard years ago. Now, if you don’t do proper maintenance, there’s a chance it might get rusted. 

Usually, baseboards are connected with tubes that help in water flow. If your Onix tube isn’t working, obviously it won’t let hot water flow. 

As a result, the baseboard doesn’t get heated. So, no heat can transfer throughout the room. 

Well, there’s a way you can solve this issue. Let me tell you what to do as soon as you detect this problem.

Solution: Activate the Power Flush Cart

So, the main problem here is the Onix tubing water flow. To solve this, you’ll have to give it a power flush. By using a power flush cart, you’ll be able to get rid of all the sludge.

Power Flush Cart

You might get skeptical about what a power flush cart actually does. If you know about it, you can just skip the next part. 

So, what is a power flush cart?

A power flush cart is a device that is designed to flush out air and debris. It cleans the loop field to ensure maximum water flow. You can also include glycol in the system using a power flush cart. It comes with a water-holding tank. The cart has solid foam tires, a hose, and a lift out. 

You’ll find the hose containing Camlock connections. Basically, air filtration happens by using the lift-out filter screen.      

Safety Precaution:

I want to give you some heads up here. There are a few safety precautions you should take while using a power flush cart.

  • You must use a single 20 amp, 120 V circuit for the electrical supply. Use an extension according to the manufacturer’s cord rating. 
  • Only do service with the help of trained professionals. Don’t risk yourself an electric shock.
  • Always transport the cart keeping it in an upright position. Make sure it’s secured and doesn’t damage the flush cart.
  • Read the Manufacturer’s Antifreeze Recommendations and Procedures properly before adding them to the system.

These are all the safety precautions you must consider beforehand. 

So, after you use the power flush cart, you’ll start noticing the flow. This is a good sign! 

Now, there’s another additional step you can follow. You can add Inhibitors to the system. It will help in getting alerts about the corrosion in the tube. 

It’s best to stay cautious beforehand. So, I’ll recommend adding that Inhibitor as soon as you solve the problem.

Frequently Asked Questions (FAQs)

What’s the replacement for Onix?

There are a few replacements for Onix. You can use Fernox, Rohmer, or Sentinel as replacements. All of them work well. You can add the power flush line and inhibitor from the same brand you’re using. These will help you with a good quality water flow. 

Onix tubing vs  PEX; which one is better?

PEX is better than Onix tubing. The main reason relies on their composition. PEX is made from cross-linked polyethylene. On the other hand, Onix is composed of EPDM. Though Onix is heavily used outdoors, it causes a lot of problems sometimes. PEX has fewer problems than Onix.  

Is rubber radiant heat tubing better than Onix tubing?

No, rubber radiant heat tubing is not better than Onix tubing. It’s because they cannot enable even heating and efficiency. They have to balance the requirements where Onix tubing doesn’t need it. As a result, sometimes they are the cause of permeability problems of the tubing.  


So, now you know where there are Onix tubing problems, there are solutions too! I tried to address each and every possible problem related to Onix tubing. 

If you’ve read this article till the end, you’ll definitely be able to solve your problem. 

Hopefully, you won’t have to worry about facing these issues anytime soon!

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