Heater question

May 9, 2015
6
Syracuse
First time posting here, but I've benefited from other postings on several occasions. I have two questions:

1) The heat exchanger on my grandmother's heater must've corroded over the winter and was leaking pretty bad. It was ten years old, so pool pro recommended replacing the whole heater. He wasn't going to have time til early June to install the new one, so I did it myself. Hooked everything up without a problem, but when the heater went to fire (it's a Hayward H250) the LO error code displayed. I knew this meant inadequate water flow from the previous unit. Looked a few things up and discovered the old heater wanted a minimum of 20 GPM, new one wants a minimum of 25 GPM. The manual mentions that the water pressure switch has an adjustment to allow for variations in altitude. I loosened the adjustment a bit, and now the heater fires just fine. My question - is making this adjustment going to hurt the heater at all? And if so, what alternate solution could I use?

2) My sister has a Sta-Rite SR333NA heater for her pool. Last year I had to replace the blower as some mice took up residence in there over the winter. Same thing happened this year (with the mice), but having a different problem. Heater turns on, blower starts, then Service Heater LED lights as well as AFS LED on the control board. Ordered a new air flow switch, but it won't be in til next week some time. To be sure that is the only problem, I jumpered the two wires attached to the air flow switch together. When I did that, the heater turns on, Heating LED blinks for about ten seconds, (blower does not start at all), then Service Heater LED lights. No LED's on the control board are lit, and the LED on the ICM blinks three times. I replaced the control board - it arrived very quickly thanks to Amazon Prime - but the same thing happens. I did some research and had my brother-in-law test the voltage on the ICM, he said it checked out fine. (he isn't terribly handy, so I might re-test the voltage to be sure) Any ideas what the problem could be? Again, pool pro is coming to check it out, but he's already booked through early June and I'd really like to get this fixed ASAP.

Thanks for any advice!
 
for question 2 you may need to be a bit creative when testing this one. On newer models, the board looks for the switch to be open at startup then closed as the start sequence starts. This is to prevent people from bypassing it.

It would be best to start troubleshooting this by ensuring there are no blockages in the fan or exhaust tubes. Also ensure that the fan is in good condition (no missing vanes, etc). A lot of times there may also be a blockage of the vacuum tube port on the blower housing. If you are sure this is all good and have access to a manometer you can check the vacuum pressure on the line to be sure it is sufficient to close the switch on the AFS.

If you still suspect the AFS, unhook the wires and get a jumper wire ready to plug into the two wires. Plug one end into one of the terminals and have the other one ready to plug in. Start the heater and after about 2-3 seconds, plug in the other end of the test lead to the terminal. This will fool the board into thinking that the system is connected as it is normally. If the unit fires then the AFS is bad .

You can also use a volt/ohm meter to verify the switch is closing properly by measuring voltages at each connection thru the safeties. ?This can also help pinpoint which switch might be bad
 
Question #1. Hayward does not recommend adjusting the pressure switch unless altitude is involved. The 25gpm is necessary for the heater to work correctly. Adjusting the pressure switch to work on lower flows could damage the heater in time. Not what sure what pump you have but 25 gpm is fairly low.
 
Thanks danpik - I've been out of commission with the flu but back at it this afternoon. The new AFS still hasn't arrived, but I tried doing as you suggested. With the test AFS wire open, the heater powers on, the blower starts, and the Service Heater LED comes on immediately. Once I close the circuit, the GFCI outlet pops and everything shuts down. Hoping the new switch will fix this, but any ideas in the interim?
 
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.