[2BirdDogs]

When I am using Aquahot on electric only and the heating element is “on” (I can tell due to L1 and L2 being over 30 amps each) my bathroom heater fans pulsate and there is a relay in the electrical controls bay (above and between my Outback inverters) that clicks on and off in sync with the pulsating heater fans. Any ideas on what may be causing this? I thought it may be to allow the electric element to get the AquaHot up to temp before allowing full force through fans but not sure. It does not do this when I am running diesel burner only. 

I will attempt to attach photos of the relay. 

Appreciate any insights. 

Paul

[2BirdDogs]

Here’s a link to videos of fan and relay:

https://photos.app.goo.gl/kKD99GmYvC5AynsSA

[Jack Houpe]

What is the black relay with the red knob below the clear relay? Is that a timer relay? When you turn off the 220 element of the AH does the fans operate normally?

[2BirdDogs]

Thanks for your reply Jack.

I think the black box is a timer that is there to keep the AC's from coming back on all at once in the event of power failure. It is somehow connected into the AquaHot Electric Heat mode too since the element amp draw is so high Leg 1 and 2. I think the black box timer and relay may also be part of the system that locks out the heat pumps when AquaHot is on electric element but I am not sure.

The bathroom and 1/2 bath aquahot heat vents ONLY pulsate when the electric AquaHot element is energized. 

Once the AquaHot comes up to temp and the element is not drawing any current, the bathroom heat vents blow normally. The bathroom aquahot heat vents are controlled by stand alone "old style dial" thermostats.

Zone 1 (kitchen Aquahot vent) and Zone 3 (under the bed Aquahot vent) blow normally all the time regardless if the electric element is energized or not. Zone 1 and 3 are controlled by the main AC thermostat via gas heat setting.  

The relay pulses anytime the AHot electric element is energized (even if the bathroom heat vents thermostats are turned all the way down / off).

Thanks again,
Paul

[Richard]

Paul,

I don't know how/why the black box is in the circuit. But I recognize that black box. It is a common delay device used on home air con systems to prevent the compressor from short cycling. It is typically delay on break, meaning that once the circuit is broken, a timer starts and it will not energize for the specified time. It appears you have an adjustable version.

Can you trace the wiring coming out of the black timer device to see if it indeed is going into the clicking relay?

Is this a new phenom? And I assume you want it to stop?

[Jack Houpe]

Has there been any repairs to either the HVAC or the aqua hot recently?

[2BirdDogs]

Paul,

I don't know how/why the black box is in the circuit. But I recognize that black box. It is a common delay device used on home air con systems to prevent the compressor from short cycling. It is typically delay on break, meaning that once the circuit is broken, a timer starts and it will not energize for the specified time. It appears you have an adjustable version.

Can you trace the wiring coming out of the black timer device to see if it indeed is going into the clicking relay?

Is this a new phenom? And I assume you want it to stop?

Thank you Richard. 

Sorry for delayed response... I had a family need that took me away from things late last week until today. 

1. I will trace the wiring tomorrow and report back. 
2. Not a new phenom. I noticed the pulsating when we first got the coach 3 years ago but I just noticed the association with the relay in the electronics bay a few weeks ago when it was quiet in the coach and I happened to hear the relay clicking through the floor under the dining table (at the same time I noticed that the aquahot electric element was energized and the two bathroom heater fans were pulsating).
3. Yes I would like to figure this out and stop the pulsing fans.

---

Has there been any repairs to either the HVAC or the aqua hot recently?

Thanks Jack.

NO repairs to either HVAC or aqua hot recently.

[cwl1979]

Trace the wires and look for a loose ground, as soon as i found my loose ground my bathroom and bay heater fans stopped pulsing. If you don't have the service and installation manuals for your Aqua-Hot, I would recommend them. They can be downloaded from Aqua-Hot. very helpful with trouble shooting.

[2BirdDogs]

Trace the wires and look for a loose ground, as soon as i found my loose ground my bathroom and bay heater fans stopped pulsing. If you don't have the service and installation manuals for your Aqua-Hot, I would recommend them. They can be downloaded from Aqua-Hot. very helpful with trouble shooting.

Thank you Carl. Will be tracing today and will download the manuals.

[2BirdDogs]

Update: issue resolved

Creslie helped get me in touch with Henry at Newell and after we discussed the issue he suggested I replace the relay. He and I agreed that it sounded like the coil may have become weak to the point that when the voltage dropped as the Aquahot elements energized the coil could not hold the fan contacts closed and caused the pulsing.

Looks like he was right as I replaced the relay today and no more pulsing. I got the relay new from Amazon for $40.

Thanks for all the input on this thread. Always feels good to resolve an issue and be able to share good news. Hope the fix holds.

Have a good week ahead.

Paul