How To Test A Condensate Pump?

Before any testing can begin, it’s essential to ensure that the condensate pump is properly installed. This includes safely mounting the unit. It also involves connecting the inlet and discharge lines. Finally, wire the power supply as the manufacturer says.

Once the installation is complete and you've gone through your checklist, you're ready to move on to testing the pump's performance.

This guide provides some best practices on commissioning a condensate pump. 

Check List:

1. Check the pump installed has the flow rate for the condensate being produced. Most condensate pumps are not rated for 100% duty, we recommend that a duty cycle of 50:50 at peak times (i.e. the pump only runs at peak time 50% of the time). Consult the manufacturers' duty recommendations, if they don’t provide the information then never go above 60% on time.

2. Check the pump can handle the discharge length. Most tank condensate pumps use centrifugal pumps; the performance of this type of pumps can be negatively affected by how the discharge hose is laid out. A 90° degree bend on a discharge line can affect the flow rate by as much as 25%, multiple 90° bends can have a dramatic effect on flow rate and pumping head. 

Having a horizontal run before any vertical lift can also cause reduction in flowrate and vertical lift. The best installation for centrifugal pumps is to come vertically out of the pump to the maximum head and then put a 10° - 20° decline on the discharge line. This will allow you to use gravity to move the condensate along a longer horizontal path.

1. Ensure the power supply feeding the condensate pump is suitably rated and protected with an electrical safety device. We also recommend the pump is fed also from a permanent supply, best practise it to feed the pump from a separate supply than the air handler, this can prevent water spillage if the air handler is switched off and the residual condensate on the cooling coils can be removed.

2. Check if the pump has a built-in check valve or one needs to be installed in the discharge line. Check valves prevent the condensate from feeding back into the tank once the pump has turned off. Most manufacturers include a check valve with the pump, but some don’t.

3. Ensure all liquid connections are secured and suitably clamped to prevent water leakages and working loose because of vibration.

The next step is to test the pump, and this is done by simply manually filling the tank or drain tray until the condensate pump switches on. Repeat the process until the condensate is discharged from the end of the discharge line. This ensures that when you carry out the final test you have the maximum pressure on the discharge line. 

You can easily test the installation by calculating the drink cycle time of the condensate pump and compare it to actual time. Most pumps have an approximate drink volume of 50% of the tank capacity, if the manufacturer of the pump does not supply a drink capacity value, then assume 50% of the tank capacity. 

Example:If we assume a pump has a 1.8m head and a flow rate of 110 l/hr at 1.8m and the tank capacity is 1 litre.The drink cycle volume is 0.5 litres.The equation below provides a simple method of calculating the drink cycle time in seconds from the drink cycle volume and flow rate at the given discharge head. 

𝑫𝒓𝒊𝒏𝒌 𝑪𝒚𝒄𝒍𝒆 𝑻𝒊𝒎𝒆 (𝐬𝐞𝐜𝐨𝐧𝐝𝐬) = 𝒅𝒓𝒊𝒏𝒌 𝒄𝒚𝒄𝒍𝒆 𝒗𝒐𝒍𝒖𝒎𝒆 / 𝒇𝒍𝒐𝒘 𝒓𝒂𝒕𝒆 𝒍/𝒉𝒓 𝒙 𝟑𝟔𝟎𝟎

𝑫𝒓𝒊𝒏𝒌 𝑪𝒚𝒄𝒍𝒆 𝑻𝒊𝒎𝒆 = 𝟎. 𝟓 𝟏𝟏𝟎 𝒙 𝟑𝟔𝟎𝟎 = 𝟏𝟔. 𝟒 𝒔𝒆𝒄𝒐𝒏𝒅𝒔 

With a full head of water and the pump off, pour more water into the pump until the pump starts and time the period between the pump starting and stopping and compare the results. 

This will provide you with an easy method of ensuring the pump and discharge line are within specification. 

Once the pump is installed, check how many times the pump operates per hour (you can use 15 minutes and multiply by 4), this will provide you with how much condensate is being produced, which can be used to compare against the rated flow rate of the pump.

Hartell condensate pumps are made for reliability and long-lasting performance. They are a trusted choice for both residential and commercial HVAC uses. However, we understand that every installation is unique. 

If you have any questions during setup, testing, or operation, our team is here to help. Feel free to contact us for technical support, troubleshooting help, or product advice. We are here to support you every step of the way.