6yo NTI TFT 154 Gas/Hot Water Boiler throwing error codes (Chicago area)
Starting this morning I noticed that the heat was down a few degrees and checked on the boiler.
On the Control Snapshot screen it displayed:
Lockout 109: Ignition failure occurred
Alert 448: Flame too low
Alert 293: Abnormal recycle, Flame was lost early in run
Alert 291: Abnormal recycle, Flame was not on at end of ignition period
Alert 449: Modulation rate was limited due to flame strength
I originally thought this was due to a dirty flame sensor so I cleaned it with steel wool and it fired up normally. I also cleaned the condensate drain for good measure. When I returned home this evening the lockout 109 and alerts 291/449 were present.
I cleared the lockout and alerts and it's been working fine for the last 4 hours, but it's clear I need to do some more work.
I'd love to get some input with this situation on likely causes. Hoping it's as simple as a faulty flame rod and I can have it delivered by Tuesday.
(alert 448/449 refers to lockout 138 but that lockout never triggered)
Comments
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Hello FIshermanPete,
I'd say much more to check.
https://ntiboilers.com/wp-content/uploads/2018/12/TFT-Series-IO-Manual-2018-09.pdf
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System1 -
How old is your igniter? Also, when you cleaned out your condensate did you make sure the line that it connects to was also clean. I just had one like that, a little baffling, I pulled condensate off and after pulling the lid off the top of the HX I started pouring vinegar into the HX and it wasn't coming out the bottom. Shoved a screwdriver up there and sploosh it call came out!
Just a thought. Could be gas pressure. Lots of things to check!
Tom
Montpelier Vt1 -
Agree the list is long for things to check with lockout 109, it seemed the combination with the different alerts might narrow it down to a 'most probable' issue.
The igniter is original. I haven't yet disassembled/cleaned the HX to ensure flow. I focused on the condensate trap to make sure the float/ball was not stuck, was pretty caked with sediment on inspection but is now clean.
I've subsequently tested the venting, gas valve, and spark generator and found no issues. I do not have access to a manometer to test the gas pressure. I'm willing to buy one if that is a high likely suspect based on the errors.
Would it be prudent to go ahead and buy a new flame sensor and igniter (as both are original) and install them first before disassembling and cleaning the heat exchanger? I'd prefer to put that task off until spring.
0 -
You can build a manometer.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
I ended up buying new flame sensor and spark ignitor but the issues remained. Next step bought a cheap manometer and tested the line through the recommended procedure. Static pressure was ~7.2"wc and under full modulation load dropped to ~5.6"wc. The desired line pressure under load is 7"wc with min/max equaling 4"/10.5". The gas is supplied from the street and there are no regulators on the line making adjustment not possible. Assuming the 5.6" load is what it is and not an issue.
However I did notice on the very next page of the manual it detailed the combustion calibration procedure. As alert 448 could be due to poor combustion I went ahead and turned the throttle screw 1/8 turn counterclockwise to test if the system was running too lean.
It's now a week later and there have been no more alerts or lockouts. I know a proper combustion test is warranted and will address in the spring when cleaning the heat exchanger.
1 -
Just FYI, generally speaking with any condensing boiler if you see a 1" pressure drop or greater that would be deemed insufficient even if the number it drops to is within the specified range. Many installs fall in this category and typically seem to be working fine…. until they don't. I would investigate that gas supply personally, no meter or anything at the house? sorry if that's a common install in the city, in my area we always have a meter on the house (natural gas), or an LP tank with a little regulator.
2 -
If there’s no regulator at the meter, you’re in a low pressure gas zone where the pressure is regulated somewhere in the street because the piping is very old.
As mentioned by @GGross, more than 1” pressure drop can be too much for some mod/cons. You really need to have a combustion analysis done by someone who’s got a digital analyzer and who knows what they’re doing.
Also, a dirty heat exchanger will throw the combustion off to where you can have the issues that you’re having.
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.1 -
Have you had a combustion analyzer on it? If it was opened for cleaning you will need to check the combustion. Yearly or every few years it should be cleaned and re-adjusted if needed.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
Just FYI " The gas is supplied from the street and there are no regulators on the line making adjustment not possible. "
This is the regulator.
Hopefully when its all tuned up you will be problem free for a while. Curious, when you get the combustion analysis done how close were you.
Your Red arrows point to the On-Off shut off valves, they are just On or Off.
The flame sensor voltage is probably just the voltage drop across a fixed resistor, if you knew the value of the resistor you could calculate the current. The value of the current is more typical with other heating equipment.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0
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