Hayward Heater Clicking/Knocking

airbur · Jul 27, 2019

I’ve had a Hayward H150FD heater running a few seasons now. It’s been stored inside during the winter and installed 3 months each summer. Recently it’s started to show “Lo” which usually is an issue with the water pressure or pressure switch.

I’ve gone through all the troubleshooting in the manual and made sure there is enough pressure. One thing is that when the heater is trying to start (and during operation) it makes a clicking/knocking noise coming from the gas valve assembly. Sometimes the heater will start but continues to click/knock. Sometimes it won't start at all.

Here's a video of the heater running and the odd noise: Download

Any suggestions? Thanks.

airbur · Jul 27, 2019

Anyone? Need to sort this out. I bought a Manometer so will check pressure tomorrow.

ajw22 · Jul 28, 2019

@ps0303 @Pool Clown thoughts?

Pool Clown · Jul 28, 2019

Two things:
1) The noise does sound like a solenoid going back and fourth between getting voltage and not. Or it could be a relay. You need to confirm that the boards next to the gas valve dont have any relays that could be the source of this clicking noise.

2) If this solenoid was indeed controlling the gas, i'm not sure that the heater would continue to fire. I would have to think there would be one shutdown, or at least a flutter during the playback of your video.

I would put a volt meter on the 2 wires (white and black) going to the valve to confirm voltage (28-32V). If you are getting CONSTANT voltage to the valve, your problem may be the valve (MV solenoid). If not, the FENWAL or IGN. controller.

NOTE: You may need to use an analogue meter because Depending on the refresh or gate time of your digital meter, it may not pick up the voltage drop in between the fast clicks.

ps0303 · Jul 28, 2019

If you place your hand on the gas valve and it is the solenoid making the noise, you will feel it.

Yes make sure you don't have fluctuating voltage to the valve like Pool Clown said.

airbur · Jul 28, 2019

Wow....great info guys! Thanks. Yes, I can feel movement on the valve when it's making the noise that seems to coincide.

Could that be caused by incorrect pressure? As in I need to adjust and check with Manometer? Or is it more I need to replace the entire valve. It's this one:

Amazon.com : Hayward FDXLGSV0001 FD Natural Gas Valve Replacement for Hayward Universal H-Series Low Nox Pool Heater : Swimming Pool And Spa Supplies : Garden & Outdoor

www.amazon.com

Thanks!

Pool Clown · Jul 28, 2019

airbur said:
Could that be caused by incorrect pressure?
No.
As in I need to adjust and check with Manometer?
No. You should not need to adjust your gas valve. Especially if it had run ok in the past.
Or is it more I need to replace the entire valve.
You need to first confirm that the clicking is either the cause, or the symptom (check the voltage).

..

airbur · Jul 29, 2019

FIXED. So my bad and apparently it was pressure out of the filter (need to install a gauge). I spent 30 minutes running water down it and churning the sand with my hand. It was a mess. After reassembly and fixing a very small leak in a pipe, the heater fired right up and has stayed on.

I don't understand the behavior of the heater though. Was it the water pressure safety valve clanking back and forth that made the noise? I don't think so as it was coming from the gas valve.

Pool Clown · Aug 1, 2019

Yes and no.
Yes it was the cause, No, the pressure switch wasn't making the noise, the valve solenoid was, as you suspected.
As soon as you dont have enough pressure the switch opens and is supposed to cut power to the valve making it close and shut down the heater (via the FENWAL). Your pressure must have been right on the cusp causing the pressure valve to open and close very quickly. So quickly that you were getting a chattering of fast clicking of the solenoid (MV). Apparently it was so fast that the valve wasn't getting a chance to close completely,