Lochinvar 80 not lighting, many new parts already

ColdCanuck

Our Lochinvar 80 which has provided great service for many years has been acting up, and now failed completely. Many service calls - however, we live in a small mountain village and service providers are scarce. Unit provides heat to both DHW and SH in our radiant floors and domestic water storage tank. Has had fairly regular maintenance.

History: Unit began to fail to light or run, Resets would get it to run for a while then quit. Boiler would light, but when the fan ramped up the flame would go out, but sometimes it would light and heat for a few hours. Unit would show "No Flame Ign" or "No Flame Running" codes. The boiler was cleaned, new igniter and flame sensor. When this failed to solve the problems service tech then did manometer gas supply and Gas Valve checks, told us we needed a new gas valve and maybe a new burner as well. This not only failed to solve the problem but now the boiler won't light at all. The service provider then sent their "best tech" to look at the problem, he was very thorough, spending hours doing many checks with manometer, voltage, piping, etc. but came away stumped.

Next was to replace the Control Board. Have spent big $$$$ and still have a dead boiler, still throwing "No Flame Ign" code. However it did once show a "G/V Relay Fail" which lead me to find a couple references to a bad Gas Valve Harness. The part number WRE2205 or 100208619 shows a harness which differs from what we have. Ours is two part, with a basic 2 wire from Control Board to GV but connects to a small gray plastic cube with a On/Off switch with a small circuit board inside. The new ones look to be one piece moulded black rubber.

Before we throw more money at this any ideas? Is this harness a known failure point which necessitated a re-design? Any help much appreciated!

GroundUp

I'm guessing this is an NKB-80 model Noble? Or the Canadian equivalent which is an Epic? I can't think of another 80k model they made. When these "techs" cleaned the unit, did they completely disassemble the top half and scrub the heat exchanger, clean out the venturi, replace the burner, etc or simply flush it out and tell you they cleaned it? Did they use a combustion analyzer to adjust the gas valve to proper spec? 99% of the time, flame fail: ignition/running are a combustion problem and based on your feedback of it locking out toward the top end, I would still stand by that assumption. Often the mixture runs lean (low CO2 readings) and locks out on flame fail: running, when the high fire is out of adjustment. If they replaced the burner and gas valve without an analyzer, I'd bet my house that's the problem here. Are they simply firing the parts cannon at it or are they actually working through and documenting the issues with tech support? Tech support can't/won't do anything unless the technician is standing there with a combustion analyzer and since you never mentioned a combustion analyzer, I'm wondering if they may have been just guessing and hoping… Can you clarify this, please? If they had an analyzer, they should have left a printout or two with the unit (looks like a paper receipt). If you can find those, please share photos or at least the CO2 & O2 readings. Also, there is a 3A fuse plugged into two female spade connectors located behind the transformer (to the right of the display, there are 4 spot welds that hold the transformer behind that gray cross bar) which will sometimes cause the GV relay fail message if the fuse is bad or loose.

JUGHNE

I did get that code on my Lochinvar 80 after several failed flame codes and resets.

The tiny wire pulled out of Molex cube.

It was the 100208619 cable you can see on the SupplyHouse.com site.

I did manage to force the stabs out of the grey cube/plug with small nail. Then solder the wires on the stabs and force them back inside.

Still working months later.

The small on/off switch does not seem to be present, Can you post pictures of that part?

I believe the board monitors the continuity of that cable. If hanging on by one thread of copper it may work, but vibration while operating could open the circuit, drop out the gas valve giving the flame failure code.

But then recompleting the monitoring circuit to NOT show the failed GV code.

ColdCanuck

GroundUp - Lochinvar-Knight WBN 080 is the full name. Yes the burner assembly was completely opened up and cleaned. New burner and gas valve were ordered and installed after tech thought some of the manometer readings of the G/V were suspect. The day the new burner and G/V were installed the unit fired right up and ran, all seemed good until later that night when it failed again "No Flame Running" code. After a couple resets we got it fire again but it continued to fail. "No Flame Ign" code.

That's when they sent out their "best tech" who did work very diligently at trying to figure out what's wrong - many electrical tests, more manometer tests, etc. He even changed the slope of the exhaust vent pipe to achieve better drainage of condensate and vacuumed the inlet vent pipe to clean (was fine). All fuses are fine.

They did not do a combustion analysis at time of first G/V manometer readings, and not able now since it won't run. I did talk to a Lochinvar Technical phone support guy today, (although he was very reluctant to deal with a homeowner) he seemed to think the new G/V should have been adjusted and that's why boiler not firing, however that doesn't account for the fact that it started right up and ran fine for several hours before going back to original symptoms and is now dead. I was able to get it to ignite once by wiggling the G/V harness cube, but it failed to stay lit. That trick has not worked since and was the reason I suspected the harness.

JUGHNE I will try to figure out how to post photos of the G/V harness and cube and some general pictures of the setup. Thanks both for the help so far!

EBEBRATT-Ed

Not familiar with the boiler but as @JUGHNE said and your wiggling the harness shows the harness could be the issue.

mattmia2

you absolutely must adjust the new gas valve with a combustion analyzer or it won't fire properly or likely at all.

probably could put the old gas valve back in and set the combustion properly and be on your way.

the readings on the manometer would be the result of the house regulator and the pipe sizing. there isn't anything really useful to measure pressure wise on the outlet side of the gas valve.

it would be easy enough to test for voltage at the gas valve to see if the harness is intact.

ColdCanuck

Hey mattmia2 remember the boiler was working fine before it started dying and throwing these no ignition and no flame codes. Can't get a combustion analysis with it not running. Tech tested for 24vac at control board like the Lochinvar Service Manual instructed.

OK, got some pictures.

Gas valve and plug.

I found a Honeywell part number 50015704-001 on it, looked up, it's listed as Gas Valve Rectifier. 24vac to dc

General layout:

Also, can the Air Pressure device go bad?

Thanks for looking!

109A_5

Don't know how handy you are, maybe you can review some things on your own, multi-meters are inexpensive and a water manometer can be made inexpensively. The service tech should have gone through all of this.

I'd identify the point in the ignition sequence that the process stops.

https://www.lochinvar.com/lit/0948421000288296_2000546130_SERVICE%20MANUAL_WH56-WH400_Rev%20A.pdf

And does it fire up this way ?

https://www.lochinvar.com/lit/WBII-I-O%20Rev%20J.pdf

GroundUp

The gas valve, especially a new one, NEEDS adjustment. Unreal that any supposed "technician" would even think about walking away from this unit without doing a combustion analysis and adjustment. They need to come back and take care of that for FREE. There may also be something going on with the harness, but the gas valve is most definitely out of adjustment.