20 Most Recent Hayward H Series Pool & Spa Heater 400k Btu Propane Gas Milivolt Ignition H400p1 - Page 2 Questions & Answers

i the heater is functioning other than that, i would not replace anything. from the sounds of it, the actual increase/decrease button may be stuck. in any case, the heater was set with a maximum value at the factory and will not exceed 104 degrees in any case

that code signifies an ignition failure. as your system is propane, ensure that the pressure from tank is over 30psi. under that, the system may not run properly. check to be sure that all the shut off valves are in the right position. get a technician to bleed the lines. if the heater hasnt been run for a while, it is common for the LP to not flow properly. if the outside temperature is low, this will also affect how the propane works

The installation manual calls for a check valve to be installed in the line returning to the pool. it must be after the heater but before the salt generator, if equiped. not installing the check valve will void warranty

Your thermopile that tells the heater how hot the water is has failed. It should kill the heat at a temperature of 104f. This also indicates that the limits are not doing their job, as they should be killing the heat at 135f (low limit) or 150f (high limit). Schedule 40 pvc is rated at about 140f. This many failures at once is rare, and typically indicates that the heater has been rigged. Get a tech out to fix it correctly. You are literally playing with fire.

BO means that you have bypassed operations. ie automation. if no automation is present then press and hold the Down arrow and Mode button for 3 seconds.

"IF" or" Ignition failure", simply means you heater didn't fire. Be sure your gas is on,and if on propane be sure there is at least 30% in the tank (and the valve is open).Also check whether your "Glow plug" ignitor Glows, or your spark ignitor sparks (depending on which kind you have).

Additional info... "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.
• Could be debris in front of Pressure Switch, in the copper tubing
  • Unscrew and remove pressure switch, turn pump on. But first, align end of tube so that when water squirts out it will shoot out from heater and not onto electronic heater components!
• If all above is good, you may have failed pressure switch?
• Etc

Good Luck - hope this helped.

"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.

Is the heater installed indoors?? if so you'll need a vent pressure orifice kit.
if not check your water press. (below 18 PSI on filter) Place filter on "recir" if it fires and stays on . it's the pressure.
check to see if all connections a set tight hi-ltd switch wire harness etc.

Immediately? That is an indicator that your circuit board has fried. and do you mean .25 amp fuse?

Not 56, but Sb, stuck button, check the back of the control panel for corrosion. We had the same issue and found some moisture had caused a spot of corrosion blocking the contacts. Cleaned it out and worked like a charm.

That's possible...but you would definitely notice the heater doing HIP HOP dance moves and making lots of racket - banging and clanging! And your heat exchanger would've melted and pool would probably empty out as it was flooding your equipment room! because if there's 400,000 btu's of heat (Which IS a lot) being generated by the burner tray, under the heat exchanger, with very little water going thru it... What do you think the result would be???