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Cold-as-ice

New Member
Jan 24, 2024
6
Maine
Greetings!

I'm hoping someone may be able to help me with my NTI Trinity 150 questions. I've been experiencing issues with my propane boiler for close to 4 years now.

I've invested thousands in local heating contractors only to find purchased parts that were not necessary and no solution.

Boiler make/model:
2008 NTI Trinity 150 boiler system.

Here's what's happening:
The boiler continuously cycles for about 30 seconds at a time and then I receive a ACS ER3 code. Only luke warm water and temperature will not exceed 64 degrees.

During this process, the flame "eventually" lights after several cycles and stays lit for about 30 to 60 seconds before throwing the ACS ER3 code.

We've had multiple, certified technicians come out to clean it and troubleshoot. Each time a part was replaced and no solution..I have kids and we just want to be warm.

Here's what's been replaced:
• Flame Sensor
• Flame Rod
• Flame Probe
• Sentury control panel.
• Inducer motor
• Expansion tank
• Watts Air Vent

None of the above has solved the primary issue listed above. We typically have enough hot water to last for 30 minutes at a time and when really cold, we set the thermostat to 68 degrees, but the room won't heat beyond 64 degrees.

Any ideas as to what the issue could be? Can you offer any insight or tasks that I can do myself to try and resolve?

I'm attaching a link to a YouTube video I created a few years ago that demonstrates the issue. (See below)

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The other issue...I created myself, I replaced the expansion tank and drained about 5 gallons of water and introduced air into the pipes. No I just need to know which Spigot is for draining, and which levers to pull to isolate and then re-introduce water.

I'm currently between 12-15 psi and heat water flushing through my hot water baseboards. Here are a few pictures of my set up. We run propane and have a well.

[Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue.
 
ER3 indicates a bad connection on the water temp sensor circuit. The water temperature sensor is on top of the heat exchanger. I would check all the wires and connectors from that sensor all the way back to the control board. If you can, give us a clear photo of the top area of the boiler including where those grey & red wires go. You can pull those wires and do a continuity check using a multi meter. If the wiring is good, then there's a possibility the sensor itself is bad.

Do you also have the outdoor sensor installed? Wiring issues with that sensor can also result in an ER3.

To get the air out of the system, you just need to purge each zone one at a time. Close the 1" main return valve as well as all the zone shutoffs. Hook up a drain hose to the drain on the return manifold and open the drain. Then open one zone shutoff at a time until you feel cold water coming back and there are no air bubbles coming from the drain. You may open the fast-fill on your feedwater regulator to speed up the process, just be careful not to overpressurize the system.

Depending what type of system you have, you might also have air valves upstairs on some radiators that you can use to bleed the air.
 
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Your radiators should have little bleed valves you can open with a key to bleed.

You can also flush with water pressure. But that could potentially overpressure the system.
 
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Your radiators should have little bleed valves you can open with a key to bleed.

You can also flush with water pressure. But that could potentially overpressure the system.
Thank you for the recommendation. Unfortunately I don't have them on my baseboards. I do have wall panel unit in my garage thats tied into my boiler. That had the air release valves. It was so easy to remove air from that one. I wish the baseboards had them too. Thanks again!!
 
ER3 indicates a bad connection on the water temp sensor circuit. The water temperature sensor is on top of the heat exchanger. I would check all the wires and connectors from that sensor all the way back to the control board. If you can, give us a clear photo of the top area of the boiler including where those grey & red wires go. You can pull those wires and do a continuity check using a multi meter. If the wiring is good, then there's a possibility the sensor itself is bad.

Do you also have the outdoor sensor installed? Wiring issues with that sensor can also result in an ER3.

To get the air out of the system, you just need to purge each zone one at a time. Close the 1" main return valve as well as all the zone shutoffs. Hook up a drain hose to the drain on the return manifold and open the drain. Then open one zone shutoff at a time until you feel cold water coming back and there are no air bubbles coming from the drain. You may open the fast-fill on your feedwater regulator to speed up the process, just be careful not to overpressurize the system.

Depending what type of system you have, you might also have air valves upstairs on some radiators that you can use to bleed the air.
Thank you so much for your response! I truly appreciate you for taking time to respond. I also believe you're on to something here..

I created a new video showing the top of the heat exchanger. Those wires were previously encased in some kind of metal flex conduit that had been completely corroded. Rust maybe, not sure. I took pictures of it before removing and rewiring.

Here's what's interesting and why I believe you are on to something. When I put the wires back together the heating system worked flawlessly for about 6 hours. The kids were so excited that they were going to be able to take hot showers, it was kind of comical. But the next morning it went back to its system cycling routine with the ER3 code. Here's the updated video:

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[Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue.
 
Wow looks like something corrosive has been leaking right on that spot, perhaps one of those pipes above it or possibly an exhaust vapor leak?

Anyway it sounds like you wiggled the loose wire enough to get it to work for a while. I would clean up / redo all those wiring connections both inside and outside the unit. Then try to figure out what caused all that rust .
 
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I believe the water temp sensor is the second one back on the left side with the white leads coming off it, that connect to the red wires. It's wired in series with the low water cutoff which is all the way in the back corner.

I was wrong, it's the front one. Test all those spade connectors and see if any are loose.
 
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Wow looks like something corrosive has been leaking right on that spot, perhaps one of those pipes above it or possibly an exhaust vapor leak?

Anyway it sounds like you wiggled the loose wire enough to get it to work for a while. I would clean up / redo all those wiring connections both inside and outside the unit. Then try to figure out what caused all that rust .
Agreed! I'm going to Home Depot to pick up replacement wires & conduit. The corrosion is baffling, I can't tell where it originated. I wonder if it was a leak from the prior Watts Air valve. Maybe I'll see more as I remove the old wires..

Here's something interesting...see attached pictures. The nuts and bolt drilled into the PVC pipe doesn't seem to serve any purpose, and while cleaning around the area, I gently rubbed up against it, and it fell off..

[Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue. [Hearth.com] NTI Trinity 150 Hydronic Boiler issue.
 
The hole was probably drilled to insert a combustion analyzer (code required for install in some places) and the bolt... was someone's attempt to plug the hole afterwards??
 
Another random thought... During cold weather, the air intake pipe can get cold and sweat or frost up. Maybe that's what dripped on the boiler? Is your basement very humid?
 
gthomas785 is right on the hole in the pvc pipe.
try this first boost up your pressure on the water to 18 lbs some of the munchkin boilers shut down below 12 lbs. maybe your sensor is off. next on the boiler look for the T T terminals that the zone control is hooked up to and once you find it short the terminals or what i mean is use a small piece of wire and go from one terminal to the other. if the boiler works then the wire from the zone control to the boiler is bad.

i can't believe no one has looked at the sensors.
 
The hole was probably drilled to insert a combustion analyzer (code required for install in some places) and the bolt... was someone's attempt to plug the hole afterwards??
That makes sense. Well, I picked up a clamp multimeter last night to check for open circuits and while inspecting the line to the flame rod, the igniter practically crumbled in my hand. Luckily I was able to connect with a local that had one. So, I atleast have it back to cycling for this evening.

This boiler is exhausting, lol. I decided to take a break and watch a little football:)