Too Many Recyclings Error

BoilerQuest

Hi All,

I am having some issues with my Lochinvar KHN85. When the boiler gets a call for heat and begins firing, sometimes it will immediately try to modulate down to below 10% and make a groaning noise before losing the flame. It then tries again for several times before logging a "Too Many Recyclings" fault code.

When this first started happening, I though I may have had the reset curve set too low, were as the boiler couldn't modulate down low enough to match the supply required. However, it locked-out this morning an outdoor temp of ~32 degrees and a call for supply of nearly 120. Once I reset it, the boiler fired correctly and ran at 60% modulation. The manual points to an issue with the limit switches (Louver Proving Switch, Blocked Drain Switch, Air Pressure Switch, or Gas Pressure Switch) or harness connection. Is there anything else set-point wise, that may be adjusted incorrectly that would cause this issue? Any input would be appreciated.

As you probably can tell, I'm the homeowner. I am trying to learn before calling the installer for every issue.

Thanks

Leon82

The louver or drain switch is jumped on the board from the factory. The installer would have had to install them as options. Its possible the connection came loose, but I would think it wouldn't have tried to fire in that case.

It sounds like the ramp delay is set to 10% for the first stage. Does it always ramp down to 10% when it fires up?

Leon82

The groan or horn noise can be from the combustion mixture settings or sometimes the venting

BoilerQuest

Thanks Leon,

Ramp delay is Enabled, with stages 1 through 6 set to 27%, 35%, 50%, 65%, 80%, 100%, respectively. The mod factor is set to 50%, instead of 100% if that makes any difference.

Thanks for the explanation on the horn noise. Is that condition causing any harm to the equipment?

Leon82

If you're losing the flame you may need a combustion adjustment. I don't know what the modulation setting as it must be new software update from what I have

Boon

@BoilerQuest you're not alone. I'm having the same issue. It is hit or miss on my boiler and usually only when the boiler is cold[er]. I've only had one lockout.

Here is a link to the video of mine failing: https://drive.google.com/open?id=0B9RHDu3JwkMqUjRDdWJ0LWRjeHM

Others I spoke to said the boiler does modulate down to the low end on start-up. That seems to be normal.

If you're stuck and you really need it to ignite you can loosen the boot on the fresh air intake and pull the fresh air pipe out of the boot until the boiler's cycle gets beyond that low fire point in the start-up sequence. Then, reconnect it.

I'm curious: what is the software version and manufacture year/week (first four of serial number) of your boiler? And do you know if the length of your venting is less than the 50' equivalent what is specified in the manual?

Leon82

What if you made the first step 75 % for 30 seconds to warm up the chamber in the ramp settings

I have the whn and it ignites at about 60 and drops to around 40 before going to the ramp settings.

Boon

Tested mine just now. Ramp delay doesn't have an affect on the modulation at startup. The KHN [my MHN] ignites at 53% and drops as low as 10% but doesn't always hit 10%, and it only flame-fails or 'groans' at the 10% fire.

I edited-out the length of vent from my previous post to avoid this going off-topic into a vent length discussion.

BoilerQuest

Thanks for the input/suggestions everyone.

Boon,
The intake is a short run out the side of the house. Probably 12 ft of pipe max. First 4 of the serial are: 1603. Software version is BIC: 02 SEP 11 2014, DU: 06 SEP 22 2015. I also had only one lockout so far. Most time it has happened, it only shows up in the fault logs. Eventually it corrects itself and supplies heat. One thing that is a bit different from you experience is that it will happen even when the boiler is hot. Several times, I updated the reset curve or other parameters while the boiler was running. When I saved the settings, it shut down the boiler temporarily and the recyclings would occur when it was trying to start again.

Leon,
Boon is correct, the ramp delay doesn't come into play until after startup. My boiler will fire to 50-60%, then rapidly decrease down. It normally will stop somewhere north of 10% and run fine. Sometimes it drops rapidly to 10%, then loses flame.

rick in Alaska

Check your co2 settings and make sure it is set right. Don't go by book settings. I have been told around 9-9.2% is best. I have had similar issues and they seem alright after adjustments.
Rick

Boon

oops. Accidentally posted this. Never mind.

BoilerQuest

Hey all. Just wanted to provide an update in case anyone searches this topic in the future. I mentioned the horn noise to my tech this past week and he came over to look at the boiler. He told me that he is aware of the issue and is waiting for a software update from Lochinvar that will automatically adjust the fuel-air ratio and eliminate the problem I am having. He currently has 6 boilers operating that have the same issue. Once Lochinvar releases the next update, he's coming back to upload to my boiler. Hopefully that will be the end of it.

Thanks again to everyone who responded!