Oh no! My H500 broke!

josephny

Well-known member
Jun 4, 2009
82
Sullivan County, NY
I have a Hayward H500FDPASME (500,000 btu propane heater) that I bought and installed in 2017.

It's been working great until yesterday.

Control panel allows me to switch between off, spa and pool; and displays the current water temp and allows me to set a setpoint temp.

I hear a click-click which I've traced to one of the relays on the ignitor board. It click every 30 seconds or so.

That's all the unit does. Does not throw a code. Does not show signs of attempting an ignition (no gas is released, I don't believe an ignition spark is present).

I noticed the transformed is hot, as if there's something drawing current -- perhaps whatever it's actually doing when it goes click (it's actually a single click).

Interestingly, it clicks even in the off mode. As if it's trying to do something in the off mode, and failing.

Fuses are good. No codes displayed. Transformer output (I think) is around 30 volts.

I'm in the mountains, and the evenings get down to about 60, so I need the heater to keep my water at a very comfortable 84*

Any ideas?

Thanks!

Joe
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
28,491
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Have you confirmed you have gas at the heater?

Have you opened up the heater and examined the insides to see that no rodents have nested in it and chewed wires?

Post pics of the inside of the heater.

@swamprat69 may have ideas.
 

swamprat69

Well-known member
Mar 30, 2019
576
Las Vegas, NV
If you bought and installed you should have the manual. If not I think this might be it https://www.hayward-pool.com/assets...uals/UHS-Service-Installation-011717-RevT.pdf . If this is not the correct manual, it would be helpful if I had a link to it or at least a photo of the page with the wiring diagram. Your heater uses an HSI (hot surface ignitor) and does not create a spark for ignition. The HSI is silent and makes no noise. If I understand correctly the heater is making a clicking noise at a relay on the control board and you get no blower operation (the start of the ignition sequence). You also say that you get this clicking in the "off" mode. By this do you mean when the heater is on "standby"? Do you have a multimeter and feel both comfortable and safe using it?
 

josephny

Well-known member
Jun 4, 2009
82
Sullivan County, NY
@ajw22 I have not definitively confirmed gas at the heater. Tank is full and the stove in my house works. I believe there is some sort of bleeder valve on the regulator at the heater that I could use to check, but I don't know how.

Inside of heater is completely clean. Wires are intact, no rodent/insect damage, no rot or corrosion.

Removed a couple of connectors off air sensors to/from blower motor and there was some oxidation but not much.

Will post pics at daylight.

@swamprat69 I had found and read the troubleshooting sections, but there was nothing that I found helpful (which might very well be my error, and not the manual).

I did not know about an HSI -- thank you.

The click sound is definitely coming from the control board (part FDXLICB1930) -- I can feel it click with a finger touch. Relays that click every 30 seconds or so are circled in red on the attached pic.

And, yes, sorry not "off" but standby mode.

Yes, I have multimeter and am ready to measure.

Thank you both so much!
.

44459_0_201812493542.jpg
 

josephny

Well-known member
Jun 4, 2009
82
Sullivan County, NY
I had the breaker off all night.

Turned it on this morning and the heater behaved exactly the same.

But, the pump was not running (which is correct for this time of day), and the heater behaved exactly the same. I think that definitively eliminates a flow sensor issue.

Here are pics.

IMG_0995.jpgIMG_0996.jpgIMG_0995.jpgIMG_0997.jpgIMG_0997.jpgIMG_0998.jpgIMG_0999.jpgIMG_0999.jpg
 

swamprat69

Well-known member
Mar 30, 2019
576
Las Vegas, NV
In reading the manual I noted that before the control board powers the blower it checks to insure that the blower vacuum switch is not closed without the blower running. If it is closed, the board will not power the blower. I don't think that is your problem, but it is the first thing that I would check. Kill power to the heater. To try to check this without jostling open the vacuum switch contacts that may be stuck closed I would gently remove the 6 pin connector at the top right of the control board at PS/LIMITS and check continuity between the 2 blue wires at the connector. It should be open and not show continuity. If it is indeed open, I would then power up the heater with the 6 pin connector still disconnected. Does the heater still exhibit the clicking that you noticed when in "standby" mode?
 

josephny

Well-known member
Jun 4, 2009
82
Sullivan County, NY
In reading the manual I noted that before the control board powers the blower it checks to insure that the blower vacuum switch is not closed without the blower running. If it is closed, the board will not power the blower. I don't think that is your problem, but it is the first thing that I would check. Kill power to the heater. To try to check this without jostling open the vacuum switch contacts that may be stuck closed I would gently remove the 6 pin connector at the top right of the control board at PS/LIMITS and check continuity between the 2 blue wires at the connector. It should be open and not show continuity. If it is indeed open, I would then power up the heater with the 6 pin connector still disconnected. Does the heater still exhibit the clicking that you noticed when in "standby" mode?

Open between the 2 blue wires at the connector.

With connector disconnected (removed from the board), heater behaves exactly the same.

What next?

And thank you again so much for this help!
 

swamprat69

Well-known member
Mar 30, 2019
576
Las Vegas, NV
Are you running the pump when you are checking the heater? Can you tell if the gray wire at P5 on the fuse circuit board is grounded somewhere in the circuit. What voltage do you measure at P5? Does the voltage at P5 vary as the clicking takes place? Are you controlling the heater remotely or directly from the heater itself?
 

josephny

Well-known member
Jun 4, 2009
82
Sullivan County, NY
Are you running the pump when you are checking the heater? Can you tell if the gray wire at P5 on the fuse circuit board is grounded somewhere in the circuit. What voltage do you measure at P5? Does the voltage at P5 vary as the clicking takes place? Are you controlling the heater remotely or directly from the heater itself?

I checked the heater with the pump running as well as with the pump not running.

The gray wire at P5 is grounded.

P5 is 26 volts

With P5 attached to fuse/PS board, voltage continues to be 26 volts regardless of any clicking (that is, the voltage does not change when it clicks).

Controlling heater with main button on control panel that rotates between standby, spa and pool.

Does this help?

Thanks!
 

swamprat69

Well-known member
Mar 30, 2019
576
Las Vegas, NV
Yes. Try disconnecting the Display ciruit board from the control module. If the clicking stops, inspect the back side of the control module.
 

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swamprat69

Well-known member
Mar 30, 2019
576
Las Vegas, NV
It looks like the relays are labeled 12V DC. Sorry for time between responses, grandkids are visiting after more than a year and I can get quite busy at times.
 

josephny

Well-known member
Jun 4, 2009
82
Sullivan County, NY
Yes. Try disconnecting the Display ciruit board from the control module. If the clicking stops, inspect the back side of the control module.

Disconnected the display board and powered it up and heater is behaving the same as it did when the display board was connected. Tried it with the pump running and not running.

Removed the control module and inspected the back -- totally clean: No debris, no indications of burnt components, etc.

Now what?
 

josephny

Well-known member
Jun 4, 2009
82
Sullivan County, NY
Attached is a clean picture of all 3 relays.

I tried to positively ID which relay is clicking and I am not certain. I believe it is the lower right (Omron) but I could be wrong.




IMG_1016.jpg
 

swamprat69

Well-known member
Mar 30, 2019
576
Las Vegas, NV
Looks like all 3 relays are either 12V or 24V DC coils. This would seem to indicate that the problem is either with one of the 3 circuit boards (control module, display circuit board or keypad), input to circuit board from Temp sensor or the relay itself. Since it seems to occur even when the display circuit board and keypad are disconnected, you might be able to eliminate those. Will see if I can get you further help on this.
 

swamprat69

Well-known member
Mar 30, 2019
576
Las Vegas, NV
Don't think that I can go much further with this as I am not familiar with the 3 wire temp sensor that is used and also don't have any specs on operation of the circuit board. I can deduce that if the display circuit board/keypad has a higher setpoint temp than the actual water temp and the control module has determined that the blower vacuum switch is open, the next step would be to power the blower through one of the relays and close the vacuum pressure switch to progress through the ignition sequence. But what I can't tell you for sure is why the relay is cycling ( It is possible that the relay is for powering the blower, but for some reason the blower is either not getting power or there is a problem with the blower motor. Also not sure why the relay is cycling with no input from the display citcuit board/keypad.
 

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