Are Pool Heater Frost Rings Normal?

[auburnwde]

I have a Hayward HP31005T. It was professionally installed in July 2024 and we are using it for the first time this week.

The control panel doesn’t indicate any error and the pool water is heating.

Is it normal for the unit to have frost rings on the inside and ice on the coils after running for 4 hours on an 80 degree day? Starting water temp was 74

 

[JamesW]

Defrost Sequence
Heat Pro
When defrost sensor senses a coil temperature of 29⁰F, the control board cuts the compressor off but leaves the fan running for 15
minutes, the display will show only the water temperature during this time.

If temperature of sensor is 50⁰F or above after 15 minutes the will compressor restart and the heat pump is operating normally.

If the temperature has not reached 50⁰F the heat pump will go through up to 2 more 15 minute cycles.

If after the 3rd cycle the temperature is still not above 50⁰F the heat pump will shut down for 2 hours and show deF on the display.

https://hayward.com/media/wysiwyg/pdf/heaters/Heat-Pump_TSG.pdf

 

[JamesW]

This could be an indication the defrost temperature sensor is failing.

Check sensor against resistance charts on page 11.

If sensor resistance does not match with correct reading from chart replace sensor.

If resistance is correct replace control board.

 

[JamesW]

How Ice Forms on a Heat Pump.

In order to explain how ice forms on a heat pump, we first need to clarify two points of a heat pump's operation:

When a heat pump operates, its evaporator coil constantly rises and drops in temperature as the refrigerant inside it collects and releases heat.

When it falls in temperature, condensate water forms on it.

In fact, a heat pump typically produces about one gallon of condensate water per hour of operation.

When air flows through a heat pump, it passes over the evaporator coil and drops in temperature by 9° to 18°F (5° to 10°C) as its heat is collected by the evaporator coil's refrigerant.

So, when air below 50°F (10°C) passes through your heat pump, it can cool to below 32°F (0°C) and freeze the condensate water on the evaporator coil.

Why Is My Swimming Pool Heat Pump Covered in Ice? A Troubleshooting Guide - AquaCal Blog

One very common question asked by first-time swimming pool heat pump owners particularly by those living in colder climates is: Why is my unit covered in ice? Having serviced heat pumps for over 30 years, we at AquaCal know not only what causes this ice formation, but also how to prevent it from…

www.aquacal.com

 

[JamesW]

What speed is the pump running?

Can you show the entire system?

What is the filter pressure?

What is the humidity?

Heat Pump compressor runs continuously and freezes up coil

The coil in our Hayward HP21003T heat pump installed around 2009 and heating our 14,000 gal lap pool since we bought the house in 2015 turned into a block of ice a few days ago. The display showed "defrost" mode. I shut down the heat pump, let it thaw out, and started it back up. The...

www.troublefreepool.com

 

[JamesW]

Is the Fan spinning?

Is the air coming out of the top cold?

 

[JamesW]

Low or high Freon pressure.

Low Freon pressure is a common challenge that occurs when it’s too cool outside to heat your pool.

Low pressure is a sign of low temperature, meaning low refrigerant, which will freeze the evaporation coil.

Most heat pumps work efficiently as long as the atmospheric temperature is over 45F -50F.

On the other hand, high Freon pressure occurs on low flowing water pressure meaning there isn't enough water passing through the heat exchanger for the process of heat transference.

This condition can sometimes be confused with a faulty valve that appears open but closed inside the tube.

Why Does My Swimming Pool Heat Pump Freeze Up? Pool Heater Freezing Up

During the winter season, some ice on your pool heat pump is a common occurrence. However, when the whole unit is covered in ice, there is a concern for worry as your device won't function well and might be at risk of getting damaged.

sprsunheatpump.com

 

[JamesW]

Ice Accumulating inside Heat Pump

As I mentioned in a previous post I fired up my Rheem 5350 heat pump this morning for the first time. Let it run for 8hrs, pool temp increased about 2 degrees from 78 to 80 and so I even took a nice afternoon dip. Thought everything was going great until I decided to turn it off for the day (...

www.troublefreepool.com

 

[auburnwde]

Defrost Sequence
Heat Pro
When defrost sensor senses a coil temperature of 29⁰F, the control board cuts the compressor off but leaves the fan running for 15
minutes, the display will show only the water temperature during this time.

If temperature of sensor is 50⁰F or above after 15 minutes the will compressor restart and the heat pump is operating normally.

If the temperature has not reached 50⁰F the heat pump will go through up to 2 more 15 minute cycles.

If after the 3rd cycle the temperature is still not above 50⁰F the heat pump will shut down for 2 hours and show deF on the display.

https://hayward.com/media/wysiwyg/pdf/heaters/Heat-Pump_TSG.pdf

I’ve only ever noticed it displaying the current temperature but I’ll keep a lookout for DeF

 

[auburnwde]

This could be an indication the defrost temperature sensor is failing.

Check sensor against resistance charts on page 11.

If sensor resistance does not match with correct reading from chart replace sensor.

If resistance is correct replace control board.

View attachment 640361
View attachment 640362
View attachment 640363

Still under warranty and I’m not really comfortable working on it. Right now I’m just trying to figure out if its operating correctly.

 

[JamesW]

___________________________________________________________________
The heat pump takes heat from the environment and uses it to heat the pool water.

During heat pump operation, high temperature, high-pressure sub cooled liquid Refrigerant (A) is throttled by Metering Device (TXV) and turned into low temperature, low-pressure saturated liquid (B).

The two-phase Refrigerant flows through the Air Coil (Evaporator), where the liquid refrigerant evaporates into vapor by absorbing heat from the surrounding air.

At the outlet of the Air Coil (Evaporator) it becomes a low temperature, low- pressure superheated vapor (C).

The Compressor receives this flow at the suction line (D), and compresses it into a high temperature, high pressure superheated vapor, which is discharged from the Compressor (E) and flows through the reversing valve into the Water Heat Exchanger (Condenser).

The heat carried by the flow is then released to the pool water.

At the same time, the high temperature, high-pressure superheated vapor is then condensed back to high-pressure sub cooled liquid (A), which completes the cycle.

The water, which is being forced through the WaterHeat Exchanger (Condenser) by the pool pump, is thus heated as it passes through.

HEAT PUMP PROTECTION FEATURES: These heat pumps are equipped with safeguards that will stop heater operation to protect the unit in case of the following events:
• Excessively high refrigerant pressure
• Excessively high water temperature
• Loss of refrigerant
_____________________________________________________________________
Defrost function to manage evaporator coil frosting for low ambient temperature operation

Defrost Function: The Defrost function is provided to prevent the evaporator coil from freezing when the outside air temperature is near 50°F (10°C).

The temperature at which this function will operate is not exact and each unit will vary depending upon conditions surrounding the heat pump, clearance around the heat pump and heat pump maintenance.

This time period will vary from 15 minutes to several hours depending on ambient air conditions.

https://hayward.com/media/akeneo_connector/asset_files/H/e/Heat_Pump___Installation_and_Operation_Manual__51300102101RevB__ba0a.pdf

https://hayward.com/media/akeneo_connector/asset_files/5/1/51300056501_RevG_7a0e.pdf

 

[JamesW]

Check the Outlet Water Temperature and compare to Inlet Water Temperature.

Display Outlet Water Temperature:

With the heater on, press the UP key for 2 seconds.

The controller will buzz and the interface will flicker, indicating that the outlet water temperature is displayed.

After 10 seconds of no operation or pressing the the ON/OFF key, the unit will return to the main interface.

 

[auburnwde]

What speed is the pump running?

Can you show the entire system?

What is the filter pressure?

What is the humidity?

Heat Pump compressor runs continuously and freezes up coil

The coil in our Hayward HP21003T heat pump installed around 2009 and heating our 14,000 gal lap pool since we bought the house in 2015 turned into a block of ice a few days ago. The display showed "defrost" mode. I shut down the heat pump, let it thaw out, and started it back up. The...

www.troublefreepool.com

The pump is running on high (I realize that’s not a great answer). We technically have a VSP, but it’s a dumb pump on a smart system. The Omni logic can turn it on and off but can’t adjust the speed so it always stays on High. Filter pressure is 18 psi. Humidity shouldn’t be an issue today.

 

[JamesW]

 

[auburnwde]

Fan is spinning and cold air is coming out the top.

 

[JamesW]

Show all valves going to the heater.

 

[auburnwde]

Water temp displayed is 82.5
Water temp goal (plus sign for 2 seconds) is 85.

 

[auburnwde]

View attachment 640377

Sadly, my panel isn’t that fancy.

 

[auburnwde]

Show all valves going to the heater.

 

[JamesW]

Filter pressure is 18 psi.

Clean the filter.

Humidity shouldn’t be an issue today.

What is the humidity?

Fan is spinning and cold air is coming out the top.

Normal Air Temperature Differential.

This is the difference in the temperature of the air entering the coil (ambient air), and the air being discharged out the top by the fan. 15-20 degrees Fahrenheit.

Measure the actual air temperature of the air coming out of the top for comparison.