Pool heater on, but not heating

[trishalinn]

Hi there!
We are trying to get our pool going for the summer but our heater doesn’t seem to be heating the pool.
We can hear the heater ignite, we can hear and smell the gas running. The top of the heater is hot to the touch with hot air coming out of the vent. The light on the front says bo, the flame indicator light is green. We have the temp set to 84 and the pool water is currently 60.
Our heater is a not quite 2 year old Hayward H250FDN.
Any thoughts? I’m sure we must just be missing something.

 

[ajw22]

How many gallons in your pool?

Please create your signature with details of your pool and equipment.

If the heater is running it is putting heat into your pool.

 

[trishalinn]

How many gallons in your pool?

Please create your signature with details of your pool and equipment.

If the heater is running it is putting heat into your pool.

Pool is about 25,000 gallons. the heater has been on for several hours and the temp hasnt increased at all. Last year when it ran there was a discernible difference in the temp of the water coming out of the jets than what was in the pool. The water coming out of the jets still feels ice cold just like the pool water.

 

[JamesW]

What automation do you have?

Check the gas meter. It should show about 1,000 cubic feet of gas used per 4 hours.

(250000x.84)÷(25,000x8.34) = 1.0 degrees per hour expected heat gain.

Is the heater running continuously?

What is the flow rate to the heater?

Is the pool covered? If not, you can lose 1 degree per hour.

 

[Randrx2]

Is there water going through the heater? I know there should be a flow switch, but it may be faulty.

 

[trishalinn]

Is there water going through the heater? I know there should be a flow switch, but it may be faulty.

How can I tell this?

 

[JamesW]

What equipment do you have?

Do you have a picture of the system?

If you have aquaplus, check the water temperature reading from the system and from the SWG diagnostics screen.

The water temperature reading is before the heater and the SWG cell water temperature is from after the heater.

This way, we can see the temperature rise attributable to the heater.

If we know the flow rate, we can determine if the temperature rise is within the expected range.

 

[trishalinn]

Everything is Hayward, it’s not a regular chlorine pool. I’m not sure how to determine the flow rate but we have the pump turned on high. Here are some images. Let me know if other pictures would help.
We currently have the pump on high, heater on (it’s hot), I can feel water running through pipes to heater and water running through pipes that run out of the heater. The water coming out of the jets is so cold though!

 

[Randrx2]

How can I tell this?

Edited post after seeing pics.

Is the water pipe coming out of the heater warm?
Is the flow rate set per the heater manufacturer recommendation?
I cannot tell if there is a bypass around heater. It may be internal to the heater. Do you have the heater model number? There may be just enough flow going through heater to activate flow switch, but not enough to feel a heat up.

 

[trishalinn]

Edited post after seeing pics.

Is the water pipe coming out of the heater warm?
Is the flow rate set per the heater manufacturer recommendation?
I cannot tell if there is a bypass around heater. It may be internal to the heater. Do you have the heater model number? There may be just enough flow going through heater to activate flow switch, but not enough to feel a heat up.

The pipe coming out of the pipe does not feel warm to the touch.
The heater says its a Hayward H250FDN
I’m not sure how to check the flow rate? Do you mean on the pump? That’s set to high- our pool guy said it needs to be on high for the heater to run.
Here is another picture. Not sure if it’s helpful or not?

 

[JamesW]

What is the pump model number?

What speed is the pump on?

What is the filter pressure?

Is the heater leaking?

 

[Randrx2]

That heater has a built-in bypass. It sounds like the bypass is stuck open and not allowing enough water through the heater to heat it up.

You should not have to run your pump at full speed for the heater to work. If that is how your pool guy has it set up, it may have been an indication of that failure.

The heater needs a minimum flow rate of 25 GPM and a maximum of 125 GPM.

A slim possibility is that there is air caught in the heater. If you have one, very carefully cycle the pressure relieve valve on the heater. Should be located between where the 2 water lines come in. Although I cannot see it on your picture. Valve looks like the one on the side of a water heater. There is also a drain valve in the header where the 2 pipes connect. Turn off the pump and heater and open this drain valve to make sure you are getting water there.

Depending on how handy you are, you may want to inspect the bypass service cartridge to see if it is sticking. It may need to be replaced. See pic. You can check how to remove and if it is functioning here in the manual: https://hayward-pool-assets.com/ass...s/universal-h-series-installations-manual.pdf

 

[ajw22]

If the heater is running the BTUs are going somewhere. Either into the water and pool or out the exhaust. If the heater internal or external bypass was open then the BTUs would go up the exhaust and trigger the HLS or SFS as it would overheat.

Without a pool cover a lot of the 1 degree an hour heat the heater can generate can be lost this time of year.

 

[Randrx2]

I am sorry. I reread your original post and see you have the "b0" code. This means the control module is in bypass operation. Do you have a remote thermostat? If so, the remote thermostat may be faulty.

If not, change the setting by using the MODE key to put the heater into STANDBY. Press and hold the DOWN key and then press and hold the MODE key. Hold down both keys for 3 seconds until the indication ‘‘bO’’ is removed from the display.

 

[Randrx2]

Another thought is that it just is taking a long time to heat up. How long does it normally take to heat up? If the water is 60, then you may not feel hot water coming out of the jets in the beginning.

I still think it is a flow diverter issue. Should be easy to pull out and verify the little flapper is moving and not stuck (details are in the installation manual I linked to). Just make sure the arrow on the end of the diverter is pointing up when you are done (also check the arrow before you pull it out the diverter to make sure it is up).

 

[Randrx2]

Any resolution to this?