Troubleshooting the RP2100 ... no heat

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T

tkedge1

0
Jul 5, 2015
10
Dallas, TX
Hi All,

I am knee deep into troubleshooting this no heat issue and I'm now stuck and need some advise.

The RP2100 isn't heating anymore and I've done some debugging and here is where I'm at:

I smell no gas (first tell tell sign why I don't have hot water)
I hear no thud or commotion from the gas valve at all
I hear no zapping sound from the igniter
I have a green power light
I have no alarms
I've turned the gas on and off at the inlet
I've powered down and turned the gas off on the gas valve (everything turns easy)
I've checked the burners, not rusted, I've checked the pilot igniter and cleaned around it.
I've powered it down and removed all the connectors and reseated them
I've removed the PC Board and reseated all those connectors as well.

When I reset the system a red light comes on for a second then I get the green power light, red light clears, everything indicator is good... the spa is on, the heat light is on, the panel in the house lets me change the temp, just still no spark, no flame and no heat.

What-else can you guys suggest, thinking at this point I am pretty much at swapping boards but I'm open to any ideas before I spent money :)

-thanks in advance.
 
I see another post about measuring 24 volts between two terminals to confirm the board is good. I have not done that yet, I will check that tonight.

Not sure which two posts but there is only 3, I'll report back later tonight.
 
So you have automation and the heater is hooked to it. Have you tried disconnecting the heater/controller comm wire on the heater and then just run the heater via its controls?
 
I didn't unhook the wire, but the automation system has a service mode where it disables the panel, you can then push whatever button you want to activate that feature... so i hit spa, then pump filter, then heater etc.

at that point i get the power light turns green on
 
tkedge1 said:
I didn't unhook the wire, but the automation system has a service mode where it disables the panel, you can then push whatever button you want to activate that feature... so i hit spa, then pump filter, then heater etc.

at that point i get the power light turns green on
Click to expand...

But the automation system is still controlling the unit. If you have checked everything else out on the heater and it all looks good, I would remove the comm wire from the heater and try running it without the automation system being involved. If that comm wire has been chewed thru or is compromised in any way, the heater will never get the signal to turn on. Also, if there is an issue inside the automation system with regards to the heater button, the heater will not turn on. So best to eliminate that part of the equation.
 

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thanks guys, So I feel good about the panel... I have confirmed the panel will turn the heater light on and off, and yes I cranked it up to 104 degrees and let it sit there for 5 or so minutes thinking maybe each time I reset the unit it just takes some time to get ramped up. it's been solid in turning on and off the heater light, the spa light, activating the bubbles etc... and i can control all this from the service panel as well. right there next to the unit itself...

where is this comm wire you speak of? is that from the panel to the board ?

here is a pic of the board. it's a 601213 ... the old green one, not the newer tan replacement board.

attachment.php


- - - Updated - - -

thanks guys, So I feel good about the panel... I have confirmed the panel will turn the heater light on and off, and yes I cranked it up to 104 degrees and let it sit there for 5 or so minutes thinking maybe each time I reset the unit it just takes some time to get ramped up. it's been solid in turning on and off the heater light, the spa light, activating the bubbles etc... and i can control all this from the service panel as well. right there next to the unit itself...

where is this comm wire you speak of? is that from the panel to the board ?

here is a pic of the board. it's a 601213 ... the old green one, not the newer tan replacement board.

attachment.php


- - - Updated - - -

to clarify, from the service panel if I turn OFF the heat the power light on the RP2100 goes out... if I turn heat ON, the light comes on... so I know it's getting a signal from the panel.
 

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tkedge1 said:
to clarify, from the service panel if I turn OFF the heat the power light on the RP2100 goes out... if I turn heat ON, the light comes on... so I know it's getting a signal from the panel.
Click to expand...

Ok, sounds like the automation is working. Hook the board back up and try to fire. 4 LEDs upper right are diagnostic. So are 2 near the bottom "SENSOR" and "FAIL". See if any of them come on. I'm thinking the Heaters water temp sensor has failed (left side center of board 3 wire... may be 2 wire.).
 
Okay so finally got some time to check the LEDs on the inside.

I opened the lid so I could see the lights as I fired up the spa, heat set to 104, current spa temp is 92 and the only LED that lights is the right one of the pair that are labeled overtemp sensor and fail.

The "fail" light comes on then goes off.

When I turn off the heater the sensor light comes on and then fades as it powers off.

This is the pair of lights labeled over temp sensor fail.

Does this mean I should try the sensor first ?

-thoughts ??
 
Solid light with power on (not momentary) is failure. Light that comes on momentary as powering off is normal.

IOW, board not showing failure (may be in denial).

IIRC, the front has a light "call for heat", yes? If you aren't getting that light something isn't being satisfied. still could be water temp sensor (lower temp than set point is one thing that needs satisfy). Fail light on board would only report open sensor. Sensor could still be working, just reporting the wrong temp so heater wont fire, i.e. 150 degrees or something like that.

Sensor cost is lower than board or Fenwall so...
 
on the front panel I just have a power light... i do not have a "call for heat" light.

I don't see a specific call out of what sensor, looks like there is a thermal cut off and a thermostat sensor.

I assume thermostat sensor, I didn't see this item, not sure where it goes...
 
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