Heater efficiency question.

[Bwdonohues58]

I have a Hayward pool heater, H400FD in my 10,500 gallon indoor pool. This is a very large heater and I installed it new in June of 2020. It has a safety feature that won't let the heater fire up unless the flow rate is above a certain level, around 2200 rpm (this is a good thing). I run the Pentair variable speed Intelliflo pump 24/7. 8 hours a day at 2250 rpm (speed 2) and then 650 rpm the rest of the time (speed 1). For the first 20 months or so, having it come on speed 2 at 8:00 am each weekday, the pool came up to our therapy temperature of 95 degrees by 9:00 am without any problems. Since about 2-3 months ago it has definitely taken longer to come up to temperature. I now have it come on at 7:30 am just to make sure we will be ready for the first clients at 9:00 am. I could probably get away with 20 minutes earlier. I have made several calls to Hayward customer service about this and have spent a long time on hold and have given up. I really don't see this as a problem unless it means that there is possibly something wrong with the heater or possibly something has built up in the heater pipes, etc. I am wondering if anyone has ever noticed a drop in efficiency of a pool heater and what the cause/remedy was?

 

[Poolbreh]

I would have an hvac certified tech that also works on pool heaters come out yearly and inspect and clean, especially if the heater is indoors as well. It could be soot build up in the exchanger, poor or lazy flames, ventilation, build up inside the exchanger.

 

[1poolman1]

You may have some clogged burner orifices, most likely spider nests. Every one that is clogged de-rates your heater. I believe you have 8 burners in your heater, each rated at 50K btu. If one is clogged you now have a 350K btu heater. Clog two, a 300K and so on. I've seen these with half the burner orifices clogged and the customer wondering why it takes so long to heat the spa now. Firing the heater at least twice a month in Spring thru Fall and at least once a month in Winter usually keeps them clean.

 

[ajw22]

You may have some clogged burner orifices, most likely spider nests. Every one that is clogged de-rates your heater. I believe you have 8 burners in your heater, each rated at 50K btu. If one is clogged you now have a 350K btu heater. Clog two, a 300K and so on. I've seen these with half the burner orifices clogged and the customer wondering why it takes so long to heat the spa now. Firing the heater at least twice a month in Spring thru Fall and at least once a month in Winter usually keeps them clean.

He is in Alaska and probably runs his heater almost every day.

 

[Bwdonohues58]

I would have an hvac certified tech that also works on pool heaters come out yearly and inspect and clean, especially if the heater is indoors as well. It could be soot build up in the exchanger, poor or lazy flames, ventilation, build up inside the exchanger.

Thanks so much. I will ask the Plumbing and Heating people who installed it to come out and inspect.