Top 20 Hayward H-series Electronic Gas Pool Heater H400 Questions & Answers

Standby is actually "off". You need to press status until "Pool" or "Spa" is selected than adjust your temperature

That means low water flow is being sensed by safety flow sensor - normally a pressure switch. It s most cases not a problem, it is just doing its job, informing you that water flow has become restricted and reduced. Most common problem = Dirty filter! either backwash or rinse off the elements. If you have an automated system attached to this heater. It will always show, when heater is Off, this is normal. But it should go away, when pump comes on, if not - check for whatever could restrict water flow to the heater.

make sure you have adequate gas pressure

Open the main door, locate the 2 white fabric coated wires, they go down towards the base of the heater. This is your igniter, usually a 5/16 nut driver will be the tool you need to remove it.

that is the ignition control (fenwall)

"LO" is simply informing you that the Heater is not sensing proper water flow through it! A Flow Problem. A special sensor, called a pressure switch is this source. But... That does not mean it is bad - No, it is in most cases just doing its job! Most common reason - Dirty Filter. A good cleaning of the cartridges, or maybe a breakdown and recharge of a DE Filter, or a good cleansing backwash of your sand filter, will remedy this situation. Or... Check for any OTHER reason or situations water flow may be reduced through the heater:

• enough water in pool or spa?
• If you have a weir gate in skimmer, is it stuck in the UP position?
• Are any valves closed?
• Do you have a bypass valve at the heater?
  • If open, this will reduce the amount of water going thru heater, close it to the point, LO goes away.
• Etc

Good Luck - hope this helped.

The two may be related? If the right problems are present... HS = High Limit Sensor SF = Temperature Sensor or Thermistor Heaters Maximum Water Temperature has been Exceeded. Heaters Set temperature not in line with actual water temperature. A few reasons this occurs...

• Low water flow thru heater, check :
  • Dirty Filter
  • Opened By Pass Valves
  • Plugged pump impeller
  • Dirty/Full baskets at skimmer or pump
  • Anything that may reduce water flow
• Sensor could actually be doing its job, in a different aspect, Thermostat failure, and water is overheating in spa or pool?

But anyway, your heaters fault code you asked about is does not necessarily mean they failed. They are informing of a problem.

BO code is bypass operation. It means that it is set to operate with an external controller. Things like Aqualink, Aqualogic, Intellitouch, EZ-Touch are all types of automation / external controllers. They have their own temperature sensor and allow remote control operation. To truly find the nature of your issue. I'd start by taking it out of bypass operation and see if the unit fires by itself ( without automation hooked up to it ). The fault may lie with the automation system. You never know.

already answered your earlier post. the code LO signifies that there isnt enough water flow to allow the heater to run. as for the temp, i wouldnt worry about the display. it will never exceed factory setting. sounds like a stuck button

pull off the side panel, the thermistor is located in the header and can be removed by backing out the nut, and then pulling the sensor straight out.

check to see if proper gas pressure call gas company give them added total thems all your appliances use they probably will give you a bigger meter then everything will run efficiently

go to pool store and spend the money on Alladin or Magic Lube. It is a bit expensive and a good sized tube but its designed for your pool system. use it on all your gaskets and threads. DO NOT USE PETROLEUM BASED (vaseline)

to start with the basics, make sure there is enough water flowing through the system to activate the heater. you can put sand filter in whirlpool or bypass mode. if there is enough flow through the system, make sure the heater isnt on bypass. make sure that the gas supply is turned on at the heater AND at the meter. if your heater has a pilot light, make sure it is lit. if you still have issues, you will have to get a service company in

ensure your getting 24volts to display circ board. you will probably need to replace the display screen

http://www.hayward-pool.ca/pdf/manuals/Manual285.pdf this manual will show most of the wiring needed. it is recommended that you hire an electrician to hook up the high voltage portion.

according to hayward, this code does not exist. i dont know what else to say.

you have an open safety circuit. usually the pressure switch. clean out pump basket, back wash filter to start. you may have a faulty pressure switch

check your gas pressure if not enough it will do that it is a safety

Hayward madeComfortzone heaters and most of the parts are long gone. Sorry

pump basket may need to be cleaned out...sand filter may need to be backwashed....cartridge filter may need to be cleaned out