Most Common Hydro Shark Boiler Problems and Solutions

Hydro Shark Boiler Problems


Hydro Shark boilers are popular heating systems that use natural gas or propane. Despite their reliability and efficiency, boilers can sometimes experience problems.

So, What are the most common Hydro Shark Boiler problems?

Hydro Shark boilers don’t heat the water enough due to high water flow, glycol-water ratios, and low amp draw, bleed the radiator, and add water to balance the glycol-water ratio. But if the boiler doesn’t heat water at all due to electrical problems, too low water flow, or tripped safety cut-offs, reset the cut-off, repressurize the boiler, or clean the flow sensor.

In the next sections, we will focus on two of the most common problems of the Hydro Shark boiler.

Hydro Shark Boiler Problems and Solutions

Before we move into the detailed discussion, let’s see a brief overview.

Problem  Reason Solution
Water Not Hot Enough Low Amp Draw Check the Current Flow
Water Flow Too High Bleed Your Radiators
Glycol-Water Ratio Too High Fix the Level of Glycol
No Hot Water No Power to the Boiler Check Electrical System
Safety Cut-Off Tripped Reset the Cutoff
Low Water Pressure Repressurize the Boiler
Clogged Flow Sensor Clean or Replace the Sensor


Now, let’s discuss all the problems and their solutions.

hydro shark boiler problems

Problem One: Water Not Hot Enough

Reason One: Water Flow Too High

Having too much water pressure in a boiler can disrupt the flow of water, resulting in insufficient heating.

Solution: Bleed Your Radiators

To bleed a radiator, you need a radiator key which can be purchased from hardware stores. 

Firstly, turn off the heating system and wait for the radiators to cool down. Locate the bleed valve on the radiator and insert the radiator key into it. Turn the key anti-clockwise and release the air. 

Keep turning the key until water comes out and quickly turn it back clockwise to close the valve. Repeat this process for each radiator starting with the one closest to the boiler. 

Once all radiators are bled, turn on the heating system and check that each radiator is heating up properly.

Reason Two: Glycol-Water Ratio Too High

Maintaining the correct ratio of glycol to water is important for boiler systems that use glycol water. The correct glycol ratio is important because it affects the performance and efficiency of the boiler. 

Solution: Fix the Level of Glycol

You can test the level of glycol using a refractometer. Here’s how- 

How to Use A Refractometer to Test Glycol Concentration

Note down the reading and refer to a glycol concentration chart to determine the concentration of glycol in the system. If the concentration is higher than recommended, add water to dilute it.

Reason Three: Low Amp Draw

If the boiler’s flow and glycol ratio is fine, the boiler has a problem with any one of its heating elements. The heating element draws a certain amount of amp from your electrical system. 

If the amp draw is less than what it’s supposed to be, then the heating elements are not working or there is not enough electrical supply.

Solution: Contact a Mechanic

Your Hyrdo Shark boilers have heating elements and if the water is not hot enough for you, one or more heating block elements may not function correctly. You will probably need around $200-$600 to have a mechanic come and fix it.

Hydro Shark Boiler ProblemsSource: Stiebel Eltron

Problem Two: No Hot Water

Reason One: No Power to the Boiler

A prominent reason for your boiler not heating water could be a problem at its root, the electrical system malfunction and consequently no power to the boiler.

Solution: Check Electrical System

To troubleshoot a power issue causing no hot water, you should check the wiring connections and voltage with a multimeter. Then, check the circuit breaker or fuse box, and if none of these solve the issue, have the control board checked by a professional. 

Reason Two: Safety Cut-Off Tripped

If you’re heating a 40×60 shop with a Hydro Shark boiler, it’s essential to keep an eye on the safety cut-off switch. The Hydroshark boiler is equipped with a safety cut-off switch that is designed to prevent overheating. 

If this switch is tripping frequently, it could indicate a problem with your boiler or heating system. To fix the issue, you will need to manually reset the switch.

Solution: Reset the Cutoff

To reset the high-temperature cut-off switch, follow these steps, 

Step 1: Isolate the electrical supply to the boiler

Step 2: Remove the boiler casing

Step 3: Locate the switch

Step 4: Press the small red button to reset it. 

Step 5: Replace the boiler cover

Step 6: Turn the power supply back on

The boiler should operate normally. If the switch continues to trip, adjust the operating temperature of the boiler to prevent it from activating frequently.

Reason Three: Low Water Pressure 

This can occur if you have the wrong size pump for the boiler. So, make sure you have the right size gas line for your garage or home.

Solution: Repressurize the Boiler

To repressurize a boiler, it is important to identify what type of system is used: a filling loop, filling key, or keyless filling link. 

For a filling loop system, turn off the heating and connect the filling loop to the filling taps, then open the isolating taps and check the pressure gauge. 

For a filling key system, turn off the heating, locate the key under the bottom panel of the boiler, insert it into the black unit, turn it to engage, and turn the white nut anti-clockwise until the correct pressure is reached. 

For a keyless filling link system, turn off the heating, locate the blue keyless filling link, and pull and hold down the valve to allow water into the boiler while checking the pressure gauge. 

Once the correct pressure is reached, release the valve and turn on the central heating to check the water pressure and radiator heating.

Reason Four: Clogged Flow Sensor

A clogged flow sensor in your boiler can lead to problems with heating efficiency, hot water supply, and even boiler failure.

Solution: Clean or Replace the Sensor

If you suspect your boiler has a flawed flow sensor, you need to either clean or replace it. Here is a video guiding you through the process-

How to Replace the Flow Sensor in your Stiebel Eltron Tankless Water Heater


What Are Common Boiler Problems? 

Common boiler problems include the pilot light going out, the boiler making noises, no heating, and low pressure. Also, the boiler is not in sync with the thermostat, frozen condensate pipe, a leak in the system, and a clogged flow sensor can occur frequently. 

Should I Turn My Boiler Off If It Has A Fault? 

Yes, if you spot a fault in your boiler, such as a leak, you should turn off your boiler to prevent any potential hazards and damage. It’s best to leave any repairs to a professional Gas Safe engineer who is trained to deal with such issues.

How Many Years Should A Boiler Last? 

A well-maintained boiler that is used regularly and installed correctly can last up to 15 years or even longer. The lifespan of a boiler can vary depending on various factors such as usage, maintenance, quality of installation, and the type of boiler. 


In conclusion, dealing with Hydro Shark boiler problems can be a frustrating and challenging experience for homeowners. However, with the help of a qualified HVAC professional and some proactive maintenance, many of these problems can be addressed and resolved.

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