Hayward 400fdn repair vs. replace

Jul 21, 2015
78
Long Island, NY
Pool Size
44000
Surface
Vinyl
Chlorine
Liquid Chlorine
A pool came with the house I bought 3 years ago, including a hot tub heated by the Hayward 400fdn. It has worked fine for 3 seasons, and I believe it was at least 10 years old when I got it, so it is no spring chicken. It is controlled remotely as part of the setup.

At the end of last season right before I closed the pool, I got an IF error, and the heater sounded like it was cycling, but would not ignite, when I cycled the modes.

I just opened the pool and the heater will not ignite. I am getting a "LO" error, and when I cycled the mode it sounds like a blower comes in for a little bit, but it never ignites. These past 3 seasons it was common to see LO code, but the heater always worked when we out it on.

The pool is clean now, and I have backwashed the filter and filter pressure is normal.

Does this sound like something that is easily fixable? I would hate to pay hundreds or thousands of dollars in order to replace parts, only to find out I need a new heater, if it breaks again soon.

Given the heater is already no spring chicken, are there any opinions in the group on repair vs. replace?

Thanks for the help. I have loved all the advice on the forum.
 
A pool came with the house I bought 3 years ago, including a hot tub heated by the Hayward 400fdn. It has worked fine for 3 seasons, and I believe it was at least 10 years old when I got it, so it is no spring chicken. It is controlled remotely as part of the setup.

At the end of last season right before I closed the pool, I got an IF error, and the heater sounded like it was cycling, but would not ignite, when I cycled the modes.

I just opened the pool and the heater will not ignite. I am getting a "LO" error, and when I cycled the mode it sounds like a blower comes in for a little bit, but it never ignites. These past 3 seasons it was common to see LO code, but the heater always worked when we out it on.

The pool is clean now, and I have backwashed the filter and filter pressure is normal.

Does this sound like something that is easily fixable? I would hate to pay hundreds or thousands of dollars in order to replace parts, only to find out I need a new heater, if it breaks again soon.

Given the heater is already no spring chicken, are there any opinions in the group on repair vs. replace?

Thanks for the help. I have loved all the advice on the forum.



I just had this exact same issue, IF code is Ignition Failure Error.
If the control exceeds the maximum number of ignition retries or recycles the heater will shut down and go into lockout. Automatic reset is 60 minutes.

So I had the igniter replaced $75 part $100 labor.

If you're handy, buy the part online and change yourself.

Mine didnt help and I had to buy a new H400FDN.......$1900 on Amazon

My heater was only 4 yrs old, so you're on borrowed time, buy a new one.
 
LO Error Code = Limit string open error

If the limit string opens the heater shuts down and goes into lockout. Automaticrestart is 2 minutes after the error condition is corrected and the limit stringcloses. See below for more detail.
 
From Hayward Manual.

LO Error Code

switch fault


1. Verify that the pump is
running.


This is a normal display when the pump is off. Turn pump on. LO code
should clear. If LO does not clear, proceed to step 2.


2. Verify that water flow is
adequate


Verify that water flow rate to heater is above minimum required (20
GPM for H150FD and H200FD, 25 GPM for H250FD and H300FD, 30
GPM for H350FD and H400FD). If OK, proceed to step 3


3. Check for faulty wiring or connection.
Inspect water pressure switch wiring. Ensure wire harness terminals are
securely fastened to spade terminals on water pressure switch. If OK,
procced to step 4.


4.Verify state of water pressure switch contacts.


Remove wire leads from water pressure switch and jumper leads.
Operate heater. Measure continunity across water pressure switch.
If open, proceed to step 5. If closed, LO code is not caused by water
pressure switch fault. Remove jumper from wire leads and reconnect
wire leads to water pressure switch.


5. Ensure that low pump pressure does not exist.
Clean filter or clear blockages. Check position of valves in plumbing
system. If OK proceed to step 6.


6. Check for correct water pressure switch setting.
Adjust water pressure switch setting as shown on page 33 of Installation
Manual (only if heater is above or below water level). If LO does not
clear, proceed to step 7.


7. Water pressure switch is defective

Replace water pressure switch.
Vent pressure switch fault
(applies only


if indoor installation)
1. Check for faulty wiring or connection.


Inspect vent pressure switch wiring. Ensure wire harness terminals are
securely fastened to spade terminals on vent pressure switch. If OK,
proceed to step 2.


2. Verify state of vent pressure contacts.

Remove wire leads from vent pressure switch and jumper leads. Operate
heater. Measure continuity across vent pressure switch. If closed, LO code is
not caused by vent pressure switch fault. If open, proceed to step 3. Remove
jumper from wire leads and reconnect wire leads to vent pressure switch.

3. Check for restricted or blocked flue.


Ensure that flue is not blocked or restricted. See indoor vent sizing
requirements in installation manual. If OK, proceed to step 4.

4. Vent pressure switch is defective.
Replace vent pressure switch.
 
So as an update I had the repair man come out, and it was just a spider web in the gas line. Something I could have probably done myself if I was more confident (but I know what to check next time). Well... better a $160 visit charge than replacing the whole thing (at least for another season).
 
The mystery continues. After the heater guy got it working by cleaning out a line of a spider web, now the heater will start up. I hear the thunder and see the steam, but before reaching the spa temp, it will cut out with a LO error. In tests it would sometimes not light, and go straight to LO (I hear the fan blow, but smell no gas like I used to), and sometimes light but get a LO error and stop eventually. I have recently back washed my filter and the pressure is not near clean on the gauge.

Anyone have any ideas?

Is there an easy way to trouble shoot the pressure, such as putting the multi port value in bypass filter mode, or will this be too much pressure for the heater?
 
If you feel it is a water flow issue, if you have a cartridge filter, remove the cartridge and then run the system without it for a short time. If you have a filter with a multiport valve, one of the options should be Bypass on the multiport.
 
Thanks, I am still trouble shooting. I switched it to warning the pool, which is pulling from the skimmers rather than the hot tub drain, and the heater worked fine for half an hour, before I turned it off.

I just replaced my multi port valve, so maybe the system needed time to run everything out. I will try more tonight. Fingers crossed
 

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Hey Paul,

My question is, if my flow rate is too low for the heater, shouldn't my pressure have gone through the roof on my filter. That makes sense to me logically, but maybe it is not the case. Do you or anyone else have any thoughts?
 
So as an update, the heater worked fine for several hours yesterday. Maybe my problems a few nights ago were all caused by replacing the multi-port valve and the system just needed to run for several hours to stabilize.

Thanks everyone for all the help on this issue.
 
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