Lochinvar fan speed lock out problems

BobM1

Hi having continual problems with a Lochinvar KBN 285 with lock outs due to fan speed.  Will lock on out with low fan speed and then high fan speed right after manual reset.  In other words it is not specifically just low or high but can be a combination with a few low fan or high fan lockouts. Any ideas.  Thanks Bob M

Steve Whitbeck

fan problems

sounds like you need a new fan.

Paul Rohrs_14

Tech Services

Hi Bob,

Give Tech Services a call at your earliest convenience.  They are a sharp group of people will be able to assist you in getting this corrected.  800-722-2101 will get you thru.

Let me know if I can help further,

Paul

Slimpickins

Nice diagnosis there

Spoken like a true parts changer.



 There are several things that could cause that problem. Paul gave good info but if you're the homeowner, you probably should bring in a pro if you've never had it serviced. 

Kal Row

had this recently...

first always check air flow in and out - and make sure the condensate drain is clear - had one where condensate water was partially blocking the airflow through the heat exchanger and the float switch in in the collector thats supposed to pick that up was jammed on some dirt







the one one i just had, really was the fan and it failed because the internal auto air vent on the heat exchanger was defective and leaking and the fan sucked in the rusty conductive water right over the circuit board at the bottom of the fan thats right next to it - Lochinvar will make good on that - what can i say, it happens even to the best of products - the fan is pricey because it has smarts built in

BobM1

Thanks Kal Row

Thanks for the reminder to go back to fundamentals.  This install has a fresh air and exhaust that runs approx 3 stories and through the roof. I went up on the roof  and noticed there was no critter proof 90 on the termination of the fresh air.  In the attic there is about a 14 foot horizontal run (appropriately pitched) so that the roof penetration was in a line with other fresh air intakes and discharges for the home air exchange systems (2) and a radon discharge.  I banged along the 4" pvc but it didn't sound like any acorns, etc were bottling it up.  Back in the basement  I popped the fernco reducer, fished inside and pulled out a dehydrated flying squirrel plus a couple of dried oak leaves.  Don't remember that as being part of the install (haha).  I suspect the drill hole on the bottom of the fresh air line in the boiler was augmenting air intake given the blockage and allowing the system to operate intermittently.  Interesting observation was that without obstructed air flow the fan assembly ran smoother, quiter and without flutter right from manuel restart.  Listening to the fan for subtle inconsistency in it's operation could be a good tip off for me in future.  Thanks again, your help made my day, hope something nice happens back to you.  Bob

Kal Row

had one with a pastic bag stuck in intake...

all the way inside, also had construction foam pieces past the gas valve all the way inside the blower, - treat pvc vent on construction sites like drain pipes - tape them over until ready and make sure bird screens are in place on both - make sure sidewall vents are above the snow-line - the one with th plastic bag inside i was called to service, terminated 8" above driveway, like duh!!! - repair enough of these and u will see everything, 2 yrs ago while back we posted a picture of a wile-mclain ultra vented with with b-vent completely corroded over from the condensate - and pumped with a 007 - u cant make this stuff up!!!

however, boiler manufactures are going to have to wake up like car manufactures did in the 90s after the computer controlled emission nightmares of the 80s and put mass airflow sensors in-line - it's the only way to really know whats going on - instead of inferring it by pressure switches, fan-speeds, flame current and such ilk,  EBM-PABST sells such a system and one boiler manufacture is already using it - beside better diagnostics, such boilers would auto adjust for altitude, be able to provide 7-10 to 1 stable turn-downs - it's inevitable - only the cost is delaying it, there are a lot more car turnover than boilers so it happed faster there - today they would have to pass $500 on to the customers, ouch - but if all of them do it, it would quickly to drop to $150

anyway - was glad to point u in the right direction - never forget the basics, airflow, gas pressure and flow - seen plenty clogged GV screens, and water flow - just because pump is on doesn't mean the water is moving - assume nothing!!! had my share of pumps with disintegrated impellers

Kal Row

oops - double deleted

Steve Whitbeck

blower speed

Slim - that was a good diagnosis.

I have seen many over and under speed faults and allmost all of them lead to blower replacement.

The over or under speed fault comes up when the blower is not running at the speed that the CPU wants it to run at.

A plugged or blocked vent doesnt cause the blower to run faster or slower than the CPU wants.

With a properly operating blower it will allways be at the RPM that the CPU wants it to run at. When it doesn't you get a fault.

BobM1

Fan low speed lock out

Hi thanks for your help.  I ended up replacing the fan and everything worked well for a week.  Lock outs for low fan speed only (vs high and low fan before fan replacement) occurs several times a day now some three weeks into it.  Wondering if fan is defective.  Additionally I am having some condensate pump assembly issues namely water wants to drip out of assembly where inlet meets flue pipe adapter at back of boiler even though properly pitched.  If I disconnect flex pipe leading from condensate tank to ensure water is not back filling into tank, I still get a lock out.  I appreciate your thoughts.  Thanks