Brand new boiler, Here we go again....

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Fogshat

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So I got this brand new boiler, as you can see, this one (unlike the last one I dealt with) is installed & piped correctly. It's 100k btu CGA-4 Weil-Mclain nat gas boiler. Intermittent spark ignition. Aquastat? control module. Nest E scheduled settings 5degree difference overnight/days puts in the call for heat.
The heat space is approx. 1800sq ft. and it seems to keep it heated sufficiently.

However, the control module or ignition resets a 1000 times a day, or seemingly. It's a loud "THUNK" ... a few moments later "THUNK" .... a few moments later "THUNK" as it resets repeatedly running through the sequence of operations to detect the pilot flame.....power, stat/circ, limit, damper, flame, after which, if successful, the control opens the gas valve to ignite all the burners, OR it resets back to start at the beginning check for power, call for heat, damper open, flame etc. I got this directly from the mfr manual.

However sometimes it will finally fire up and run for 10 minutes or so then shut off. Other times it will run for 30 seconds then shut down and go right back to the "THUNK" .... a few moments later "THUNK" etc. which made me rule out the incorrect setting at the gas supply w/out even checking.

So given this information, am I dealing with defective products, such as perhaps the control module? Being an amateur (at best) this is my best guess. This unit is newly installed but I'm just trying to ensure, moving forward, that i can circumvent the bs that seems to be commonplace by technicians around here.

I have a couple videos with sound of the exact undesirable behavior so I can recreate the issue at any time for a technician in denial, & with this ranch house that thunking is annoyingly loud & will wear out the parts just days past the warranty with my luck.
Is it asking too much that the flame sensor detects the pilot, the next automatic step being the control opens the gas regulator to ignite the burners & run until the stat is satisfied and/or the upper limit is reached?

I think I have faulty equipment right out of the gate, what do you think?

I hope I sound like I have learned a few things but still hoping for any informed responses,
thank you.

Foggs

wmboiler.jpg
 

jadnashua

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Have you been through the manual and followed the indicator lights to try to determine what actually is happening? Page 37 has some troubleshooting.
 

Fogshat

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[
QUOTE="jadnashua, post: 703468, member: 24"]Have you been through the manual and followed the indicator lights to try to determine what actually is happening? Page 37 has some troubleshooting.[/QUOTE]

I did say that I pulled that right from the manual. Yeah I got the the lights on the board indicating the proper sequence is being followed and successfully all the way up to but not including the flame sensor is not correctly identifying the pilot light, it allows up to 15 seconds if fail then according to the manual it goes back to the beginning of that sequence, and it loops over and over, sometimes it gets it right off the bat and fires up sometimes it goes through to sequence three or four times each sequence is preceded by the "THUNK!" that seems to amplify in the concrete basement below us sometimes it runs through that literally dozens of times.

But I see your point since it is a warranty issue I just want to know what the repair technician should be pursuing, and disconnecting the flame sensor from the board once it's burners are up and running if that thing runs all the way up to the limit and cuts out and then you reconnect it and see if it runs right back into the same behavior then that would suggest replacing the flame sensor for starters.
Anyway thank you very much for the reply.
 
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John Gayewski

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Sounds like the gas valve is bad. Possibly got some stuff in it. Or a weak spark. Thuds are weak sparks. The gas ignites after it was supposed to. Some gas valves also have a rectifier board in them which will go bad.
 
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fitter30

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What brand and model number of the room thermostat. Thermostat might be droping out as the gas valve is opening.
 
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jadnashua

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I'd try to see the flame sensor, and verify it is not bent out of the proper location, and that the electrical connection to it is good. I didn't look to see if they have a test procedure for the flame sensor, but you can usually get an idea what the resistance across it should be.
 

fitter30

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I'd try to see the flame sensor, and verify it is not bent out of the proper location, and that the electrical connection to it is good. I didn't look to see if they have a test procedure for the flame sensor, but you can usually get an idea what the resistance across it should be.
Flame sensors creates a 4-6 dc micro amps through the flame ions to ground. Most volt ohm meters don't have micro amp scale.
 

Fogshat

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What brand and model number of the room thermostat. Thermostat might be droping out as the gas valve is opening.

That there is a Nest E, no common wire, scheduled to drop to 65 at night then to 71 day time, every day. Not set to "learn".
 

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fitter30

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Thanks yes for the download which I previously couldn't locate for some reason, although I chose to just use set a fixed schedule from the start, rather than "it learns". Just personal preference. All settings are accessible, however.
Page 13 was to check setup not the scheduling. Delivery option radiators. Page 16 with no c wire stat might not have enough power to pull in heating or cooling.
 

jadnashua

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Electronic thermostats that don't utilize replaceable batteries can only recharge their internal batteries when they're actively heating or cooling. So, depending on how often that occurs and for how long, it may not be able to recharge enough to function properly. In that case, it's always safer to have the C wire, which allows it to charge the battery whenever it needs to.

I had one many years ago that switched the circuit on/off rapidly to try to charge its battery. That works with a system that uses a relay with a coil in the HVAC system to turn things on since it wasn't on long enough to actually engage the relay, but in my case, the HVAC system was using triacs, and blew them quickly! Lesson learned. Went with a thermostat at the time with replaceable batteries that I had to change annually. On my Nest that I'm using now, I had a spare wire and was able to use it to connect the C wire.
 
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