Hayward Blower motor runs on

Willbur

Member
Feb 3, 2018
5
Clermont, FL
Hi All,

I am new to this forum and I looked a bit to see if anyone else had this issue but did not see it anywhere.

I recently bought a house with a pool and system is about 15 years old. Just the other day, my pool pump went off for the day and I noticed a humming coming from the heater unit (Hayward H250FDP). I have not used the heater since buying my house 6 months ago. The error code on the heater unit is LO with the service light on. I have a DE filter so I did a back wash thinking there was a low flow issue. That did not help. I am curious why the blower motor runs on. I don't believe there is a toggle switch for this unit and am thinking there is an automatic flow switch tied into the unit.

I am stumped and wondering if there is a bad switch. I guess i need to test for continuity on the switch. Am I on the right track?

Thanks in advance.
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
4,042
FL
LO can be either the water pressure switch, or a bad temp limit switch. It could also be a bad vent pressure switch but I doubt you have that type of setup. Since you cleaned the filter and you are sure you have good water flow, it could be the temp limit switch. You can test that by disconnecting it and jumper the two wires together.

The heaters keypad has a "Mode" button to turn the heater on/off.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
17,895
Bedford, TX
Will,

Most heaters have a pressure switch which does not let the heater come on when the pump is off or not producing enough water pressure.

If you are not using the heater I would turn it off.. there should be an on/off switch or you could just pop the circuit breaker feeding the heater.

Thanks for posting,

Jim R.
 

Willbur

Member
Feb 3, 2018
5
Clermont, FL
Thanks to all for the info.

The blower does not turn off when cycling through the modes. The service light is on. I have the breaker off for now, but it is also powering the pump so I can't run the system. What's puzzling is I haven't used the heater since I bought the house in September. The blower somehow just started running several days ago with out the heater being on.

I'll try jumpering the limit switch to see if that is the issue.
 

JamesW

TFP Expert
Mar 2, 2011
19,364
I think that it's probably a bad pressure switch. You can test the switch for continuity by removing the wires and using a multimeter.

You can check the high limit the same way.
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
4,042
FL
The Hayward units have a "STANDBY" Mode. This is similar to a power off. If the unit isn't in "STANDBY" mode, then it is either in Pool or Spa mode. You should press the "MODE" button until the "STANDBY" LED is lit up. Then the unit is technically "off" per Hayward. If the unit is in either "POOL" or "SPA" mode, then when the pump goes on, so will the heater. A caveat to that is if the pressure switch was messed with or if it is sensing enough pressure to keep the unit cycling which is not good. So unless you are using it, or unless you have an automation system that controls it, keep the heater in "STANDBY" mode.
 

Willbur

Member
Feb 3, 2018
5
Clermont, FL
The Hayward heater is in standby mode, also the service light is on at the same time the standby mode light is on. It has always been in stand by. I have never had it in pool or spa mode yet. The internal blower fan runs even though I dont have the propane tank on, or the pump on.

I am not sure if it has a by-pass for the heater. I am not too familiar with this heater as I have had a solar heater in the past.

I will test the switches with a multi tester
 

Hayward Pool

LifeTime Supporter
In The Industry
Oct 15, 2014
427
Elizabeth
The LO code will also come one when the pump shuts off and the pressure switch opens, this is normal. If the LO is lit when the pump is on one of the switches (pressure, High limit (2) or if indoors the vent pressure switch) is open. Test each one. The blower continually running could be a blower prover switch or a bad main board.
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
4,042
FL
The Hayward heater is in standby mode, also the service light is on at the same time the standby mode light is on. It has always been in stand by. I have never had it in pool or spa mode yet. The internal blower fan runs even though I dont have the propane tank on, or the pump on.

I am not sure if it has a by-pass for the heater. I am not too familiar with this heater as I have had a solar heater in the past.

I will test the switches with a multi tester
Now it sure sounds like you have issues with the main board or more wrong with the unit. If in "STANDBY" mode, the blower shouldn't be running at any time.