Ruh Roh...Boiler won't Fire w/ NEW Auto Vent Damper on Auto!!!!

AdmiralYoda

Got a weird one.  So in my infinite wisdom I thought it would be a good idea to install an automatic vent damper onto a 37 year old boiler that never had one.  Because efficiency?

The Honeywell S86F Ignition Module has a plug for one....and the Field Control universal harness has an adapter for it....so why not!!!!

Well.  Ruh Roh.  So I installed it electrically, but set it aside my boiler to monitor it's operation so I can trust it before I install it in the flue, fire it up and go to bed.

It's default setting was "Hold Open", so I kept it there and told the T-Stat to make heat.  It did!

Great!  Now here it gets weird.  Let's set it to Automatic operation!  Turned the heat up a bit....boiler ran until the Vaporstat kicked in (oversized boiler).  Pressure dropped to it's kick in point...CRAP!!!

Vaporstat clicks to create contact and the vent damper makes a little click then the vent damper motor starts closing.  Wait...what?  The boiler is about to fire up and it's closing??!!!??!

Oh wait....it keeps going...and spinning....and spinning... FOREVER!!!

Okay.  WTH...unplug the vent damper harness from the S86F, put the original jumper lug back in, start over.  Nothing.

Really????  Plug the vent damper harness back in, nothing.  Put it back into HOLD OPEN...Boiler starts up!!!

So at the moment, the boiler won't work with the old jumper harness (Bye bye one time use internal fuse?).  It won't run with the vent hood on auto...it only functions normally with the auto vent hood one hold open?

If you are still awake after reading this, then high five and I'll buy you a beer sometime.  Thanks!

And just so no one is worried...here is my observation station:

ethicalpaul

Are you sure you put the original jumper back in the same?

could some of this plugging and unplugging bent a pin or pulled off a socket pin, etc?

AdmiralYoda

@ethicalpaul good question!  I just unplugged everything and took a good look at the Molex connectors, pins and sockets.  Nothing is bent or mishaped.  All the connectors are installed correctly per the keyway on the connectors.

The T-Stat just called for heat and the boiler fired up normally with the vent damper on Hold Open.

Switched to "Automatic"...it stayed open while the boiler was running.  When the T-Stat was satisfied...the vent damper started to close...but just kept going!  Even if I turn up the heat the boiler won't turn on unless I put the damper back in "hold open".

I took the cover off the vent damper motor while it is spinning.  I'm hearing some periodic buzzing and clicking noises from the relay/motor area.  I'm wondering if the relay or internal "stop turning in the closed position switch" is messed up.  Maybe a bad vent damper?

Put it back into "hold open" and the vent damper kept spinning until it was in the open position, it stopped and made a click and the boiler fired up and everything is back to normal.

ethicalpaul

I like your thinking about this. What you described indicates to me that it's possible that the "open" position switch is working, but the "closed" position switch is not.

OR the controller isn't seeing the state of the closed position switch. I'm honestly rather ignorant of exactly how these work in regards to the signaling, but these seem like two possibilities.

But my larger concern is that things didn't work the same after you put the jumper back in.

AdmiralYoda

@ethicalpaul don't quote me on this, but I thought I read somewhere that the S86F Ignition module ( could be another model, not 100%) has an internal fuse connected to the vent damper plug.

As soon as the jumper harness is removed from the plug and a vent damper installed, the fuse blows after the boiler fired up for the first time.  After this the boiler will only fire up with the new vent damper plugged in.  The jumper harness is now useless.

I'm reaching...but that thought has been floating around in my brain.

ethicalpaul

Oh yeah I do recall that, but at least on the one I have seen, you get 10 ignition cycles before it's permanent (so it's not a fuse, but some memory in the controller). Maybe yours is older and they used to give you one shot.

From https://www.supplyhouse.com/Honeywell-S8610U3009-Intermittent-Pilot-Control-4584000-p?gclid=Cj0KCQiAjKqABhDLARIsABbJrGmHpL3Fz2hHEkzATtBF3ZVRmsjLbztFg-X_7b_SwKTk2QHs0NvShYAaAosOEALw_wcB

EBEBRATT-Ed

Make sure your limit control is in the circuit before the thermostat

AdmiralYoda

@ethicalpaul okay....time to get my hands dirty. Since my boiler is a bit older and no manual exists anymore for the Peerless G-461, I decided to create my own wiring schematic. I did this not only because I wanted to to understand how it works....but to help troubleshoot it as an overall system.

Just for reference my thermostat is a simple digital Honeywell T87 with R and W wires only. The T87 does not have a terminal for a C wire, I am only using R and W.

Here she is:

Here is the factory schematic from the Peerless Series 61 manual, which is about as close as I'm going to get to an official G-461 schematic.

So I notice a few differences between my homemade G-461 schematic and the Series 61:
1. I do not have an isolation relay. Maybe this was standard equipment on the Series 61.
2. My safety controls appear to be installed between 24V(2) and the W wire of the thermostat. On the Series 61 schematic is looks like they should be installed between the R wire of the thermostat and TH-W on the ignition module. Probably not a big deal as all we are doing is opening a circuit if a safety limit is reached.....but maybe it does matter.
3. The Series 61 schematic calls out a S8610F ignition control module. Mine is an S86F. Not sure what the difference is.

Lastly, here is the diagram from the Field Controls GVD6-PL Manual:

And the vent damper sequence of operation:

And here is a little snippet from the troubleshooting section:

Again, to recap the problem:
1. If the vent damper is left in "Hold Open", the boiler operates as usual.
2a. If I cut power to the boiler, switch the damper to "Automatic" and turn the boiler power back on...it just spins and spins as soon as power to the boiler is restored. The boiler will not ignite if the T-stat calls for heat.
2b. I can "trick" the damper. If the damper is left in "Hold Open" and the t-stat calls for heat, the boiler fires. If I switch it to "Automatic" while the boiler is running the damper remains in the open position. As soon as the T-stat is satisfied or a safety limit is reached the damper starts spinning over and over again. We are now in the same state as 2a.
3. In either 2a or 2b, if I switch the damper to "Hold Open" while the damper is just spinning in circles, it returns to the open position, stops, and the boiler operates as usual as in state 1 above.

Thanks again for the help so far!!!! Maybe I just have a bad damper out of the box? Or perhaps not having an isolation relay is making this go nuts. Or maybe I'm nuts?

AdmiralYoda

@ethicalpaul okay....time to get my hands dirty. Since my boiler is a bit older and no manual exists anymore for the Peerless G-461, I decided to create my own wiring schematic. I did this not only because I wanted to to understand how it works....but to help troubleshoot it as an overall system.

Just for reference my thermostat is a simple digital Honeywell T87 with R and W wires only. The T87 does not have a terminal for a C wire, I am only using R and W.

Here she is:


Here is the factory schematic from the Peerless Series 61 manual, which is about as close as I'm going to get to an official G-461 schematic.


So I notice a few differences between my homemade G-461 schematic and the Series 61:
1. I do not have an isolation relay. Maybe this was standard equipment on the Series 61.
2. My safety controls appear to be installed between 24V(2) and the W wire of the thermostat. On the Series 61 schematic is looks like they should be installed between the R wire of the thermostat and TH-W on the ignition module. Probably not a big deal as all we are doing is opening a circuit if a safety limit is reached.....but maybe it does matter.
3. The Series 61 schematic calls out a S8610F ignition control module. Mine is an S86F. Not sure what the difference is.

AdmiralYoda

Lastly, here is the diagram from the Field Controls GVD6-PL Manual:


And the vent damper sequence of operation:


And here is a little snippet from the troubleshooting section:


Again, to recap the problem:
1. If the vent damper is left in "Hold Open", the boiler operates as usual.
2a. If I cut power to the boiler, switch the damper to "Automatic" and turn the boiler power back on...it just spins and spins as soon as power to the boiler is restored. The boiler will not ignite if the T-stat calls for heat.
2b. I can "trick" the damper. If the damper is left in "Hold Open" and the t-stat calls for heat, the boiler fires. If I switch it to "Automatic" while the boiler is running the damper remains in the open position. As soon as the T-stat is satisfied or a safety limit is reached the damper starts spinning over and over again. We are now in the same state as 2a.
3. In either 2a or 2b, if I switch the damper to "Hold Open" while the damper is just spinning in circles, it returns to the open position, stops, and the boiler operates as usual as in state 1 above.

Thanks again for the help so far!!!! Maybe I just have a bad damper out of the box? Or perhaps not having an isolation relay is making this go nuts. Or maybe I'm nuts?

AdmiralYoda

One last observation. If I unplug the vent damper harness from the vent damper....my thermostat turns off. Similar thing happens if the LWCO, P-trol, or V-Stat opens up since I don't have a C wire.

Same thing happens when I put the original Vent Damper jumper plug back on the ignition module.

Also, if I put the damper on "automatic" the thermostat turns off, then turns back on...then the damper starts going in circles.

Lastly as a hail mary I swapped the R and W wires at the T-Stat just for the fun of it. Exact same behavior.

ethicalpaul

You seem to have all your ducks in a row to find the issue.

Have you bench-tested the damper with a 24v transformer to see if it does what it says it should do? You can verify operation of the damper that way.

AdmiralYoda

@ethicalpaul no I haven't, that is a good idea but I don't have a spare transformer. At this point I'm either thinking its a dud from the factory because it can't close properly.....or the smarts in the S86F ignition module aren't playing nice with the damper.

Or perhaps my boiler is wired incorrectly and it hasn't been a problem until I just installed an auto vent damper. Maybe the electrons aren't going where they are supposed to.

ethicalpaul

Their "Normal Sequence of Operation" chart is strangely worded, but here's what I get from it:

- put common on pin 4
- put 24 volts on pin 1 all the time. If this is the only place with power, it will be closed (this is not explicitly stated by their chart)
- put 24 volts on pin 2 to simulate the start of a call for heat. You can see this in your diagram...when the thermostat calls and as long as your LWCO and pressure controls are closed, pin 2 will get the volts
- Then when the damper opens the 24v will appear on pin 3. This gets sent to the gas valve module.

So on the bench call one of the transformer leads "common" and call the other one "24v"

Then attach "common" to pin 4
Then put 24v on pin 1. The damper should close and/or stay closed. Keep this connection all the time.
Then add 24v to pin 2 and see if the damper starts to open. It should open and stay open.
Then once it's open, you can measure between common and pin 3 and you should read 24v AC. This simulates the signal that will get sent to the control module to fire the boiler.
Then remove 24v from pin 2. The damper should close.
Then you should measure 0v between commond and pin 3

That's how I'd test it!

ethicalpaul

Time to buy a transformer

AdmiralYoda

@ethicalpaul you guys are awesome! My wife is about to kick me out if I spend any more money on "upgrades" lol....but this sounds like the next logical choice. This year I've installed main vents (didn't have any), all new MoM radiator vents, and a Vaporstat with new gauges with new brass pigtails/nipples/T's/elbows. Oh and a Macromatic TR-6512U delay timer, new 18/5 thermostat wire, a Ecobee Smart Thermostat with 4 additional sensors (not installed yet)......and an automatic vent damper.

This hobby has become quite the obsession. The wife is not amused.

Mark N

@AdmiralYoda

Do you have any jumpers to do some testing? Unplug the molex plug, jumper 1 and 4 to the secondary of the transformer steady 24volts and 2 and 3 in series between the t-stat and TH-W terminal on the ignition module. See if that works.

ethicalpaul

https://www.supplyhouse.com/White-Rodgers-90-T40F3-Transformer-40VA-60-Hz-120-208-240V-Primary-24V-Secondary-Foot-Mount-14929000-p

Steamhead

Might be time to replace the S86F. Some of the early dampers were wired a bit differently- Honeywell had their own dampers too, the D80 series IIRC. The current module is the S8610U, which has DIP switches to match the parameters of the original control, and internal diagnostics as well. But a properly operating Field damper works fine with the S8610U.

kenlmad

@AdmiralYoda

If you are inclined to continue troubleshooting ...

While the damper is rotating non-stop, use your multimeter and look for 24 VAC to appear on pins 4-BLK and 3-YLW, when the damper shaft rolls past what would normally be the normal open position. It may be just a quick momentary blip on the meter since the damper isn't stopping properly. If it isn't giving even a blip of 24vac as it rolls past the open position, you may have a failed position switch in the damper.

Based upon your damper's scant literature, here is the operating state table with meter probe positions and expected measurements. Again, the voltage measurements are AC not DC. And the 24 VAC measurement can be +/- a couple volts since those 120/24 transformers aren't precision devices.



EDIT - 1/24/2021: I Updated this table in a later post.

AdmiralYoda

Thank you everyone for your help so far. I'm taking the family out for lunch in a few and will be stopping by the hardware store on the way back for a transformer, just in case so I can do some bench testing. You guys made some sense out of the rather cryptic control logic, I'll post back with my results.

Troubleshooting this stuff is actually fun for me. As an electrical engineer (don't shoot) I typically deal with high frequency RF modules and DC control circuitry and rarely deal with AC.

I'll admit the way the schematics and wiring diagrams in the land of HVAC are constructed are rather different than what I'm used to. Give me the schematic for my TV or my computers motherboard and I'm right at home.

AdmiralYoda

okay heating superheroes....new information. Below are the results on the chart @kenlmad posted.



That 5.3VAC doesn't look right. It should be 0. Might explain why the relay sounds a little unhappy.

Onto the bench testing!!!
I picked up a 24V transformer and wired the common to pin 4 (BLK) and 24VAC to pin 1 (BRN). Turned on the power......it closed!!!!! And stayed there.

Added 24V to pin 2 (ORG) and it opened!!! And it didn't keep going, it went to the open position and stopped. If I removed the 24V from pin 2 it closed, and stayed closed.

That 5.3V not being 0 must be the culprit. Any thoughts on what might be causing that? Does anything in my wiring diagram seem off?

At this point I think its either the wiring, or the ignition module forgot what to do after 37 years.

Lyle {pheloa} Carter

Sounds like the control you have is designed to be operated with a Flare vent damper. The flare vent damper opens like a Honeywell zone valve, when power was applied it opens until it hit a stop and the power stayed on and an end switch opened to tell the boiler to fire. The dampers in use today do not have the stop . Once the power was off it would close automatically with a spring. Unfortunately flare is no longer in business.

AdmiralYoda

Thank you, @Lyle {pheloa} Carter today I'm going to fix a small issue in my wiring. My safety controls are wired a bit strange as shown below. I'm going to correct this as I will be installing a new thermostat that requires a C wire.

I don't expect this to fix the problem, just want to verify things remain operational and there aren't any new problems before I order a new ignition module.

AdmiralYoda

Okay guys. Re-wired it as in the post above. No change in operation. I'm pointing the finger at the ignition module unless somebody has more ideas.

SlowYourRoll

AdmiralYoda said:

okay heating superheroes....new information. Below are the results on the chart @kenlmad posted.



That 5.3VAC doesn't look right. It should be 0. Might explain why the relay sounds a little unhappy.

Onto the bench testing!!!
I picked up a 24V transformer and wired the common to pin 4 (BLK) and 24VAC to pin 1 (BRN). Turned on the power......it closed!!!!! And stayed there.

Added 24V to pin 2 (ORG) and it opened!!! And it didn't keep going, it went to the open position and stopped. If I removed the 24V from pin 2 it closed, and stayed closed.

That 5.3V not being 0 must be the culprit. Any thoughts on what might be causing that? Does anything in my wiring diagram seem off?

At this point I think its either the wiring, or the ignition module forgot what to do after 37 years.

am i understanding the operation correctly? is there a position sensor which outputs 24V for open and 0V for closed across those two pins?

AdmiralYoda

@SlowYourRoll It confused the heck out of me at first, but I think its rather simple...

When the T-stat is NOT calling for heat, the boiler DOES NOT supply 24VAC to the pin 2 (ORG). It should be 0VAC. Mine is 5.3VAC which is probably causing the problem.

When the T-stat calls for heat, the boiler applies 24VAC to pin 2 (ORG). This opens the vent damper and it stops and stays open while 24VAC is applied. As soon as the T-stat is satisfied, the boiler REMOVES the 24VAC from pin 2 (ORG) and the vent damper closes and stays closed.

If 24VAC is applied to BOTH pin 3 (YEL) and pin 2(ORG) the vent stays open regardless of what the T-stat wants. The "Hold Open" switch accomplishes this but it can also be simulated with jumper wires.

kenlmad

@AdmiralYoda

I know I'm stating the obvious, you could really use the elusive manual for the S86F module. Maybe there's a willing HeatingHelper that can locate one.

I put "0 ?" in the vent damper state table I posted earlier because the mfg's literature doesn't say what exactly it's supposed to be. It only says where 24VAC should be. Oddball values less than 24 VAC may be normal. Sorry if I only added to the confusion.

To provide more exact info., I measured all my voltages on the damper connected to my boiler, while it was operating normally. My measurements are specifically for my Peerless 63-04 nat gas boiler with all the stock temp switches, fuses, p-trol, and the GVD-7 damper (with the same pinout as you depicted above). My system uses a basic 2-wire Honeywell programmable thermostat.

SlowYourRoll

AdmiralYoda said:

@SlowYourRoll It confused the heck out of me at first, but I think its rather simple...

When the T-stat is NOT calling for heat, the boiler DOES NOT supply 24VAC to the pin 2 (ORG). It should be 0VAC. Mine is 5.3VAC which is probably causing the problem.

When the T-stat calls for heat, the boiler applies 24VAC to pin 2 (ORG). This opens the vent damper and it stops and stays open while 24VAC is applied. As soon as the T-stat is satisfied, the boiler REMOVES the 24VAC from pin 2 (ORG) and the vent damper closes and stays closed.

If 24VAC is applied to BOTH pin 3 (YEL) and pin 2(ORG) the vent stays open regardless of what the T-stat wants. The "Hold Open" switch accomplishes this but it can also be simulated with jumper wires.

okay, are you saying the vent damper closes and stays closed now? is that from you manually applying the 24VAC, or is that when the damper is wired into the boiler?

AdmiralYoda

@SlowYourRoll the table I posted above was with the damper connected to the boiler. If left in automatic it closes on power up briefly, then starts spinning.

When I connect it to a spare transformer on the bench using jumper wires it works normally.

SlowYourRoll

AdmiralYoda said:

@SlowYourRoll the table I posted above was with the damper connected to the boiler. If left in automatic it closes on power up briefly, then starts spinning.

When I connect it to a spare transformer on the bench using jumper wires it works normally.

oh ok thanks. i was trying to figure out if it could be the position sensor that is in the feedback loop for the motor, but if it works on the bench then that's not it. sorry

AdmiralYoda

Alright kids.  The new Honeywell 8610U ignition module came in and I installed it.  Still not working.....but different.

No relay chattering or buzzing.  When the boiler calls for heat it opens.....just never stops spinning!.  I can hear the limit switches clicking when it should stop in the open position....it just never does.

While it is spinning if I turn the thermostat down to remove the call for heat it closes correctly.  

At this point I'm about to give up and ask for a replacement auto vent damper.

SlowYourRoll

AdmiralYoda said:

Alright kids.  The new Honeywell 8610U ignition module came in and I installed it.  Still not working.....but different.

No relay chattering or buzzing.  When the boiler calls for heat it opens.....just never stops spinning!.  I can hear the limit switches clicking when it should stop in the open position....it just never does.

While it is spinning if I turn the thermostat down to remove the call for heat it closes correctly.  

At this point I'm about to give up and ask for a replacement auto vent damper.

well that is what their troubleshooting guide said...nonstop spinning = bad motor...however if it worked correctly when it was on your bench with voltage applied directly, i'm not so sure that a new one will fix the problem.

anyway, the theory i've been wondering about has to do with the feedback going on inside that motor. every motor (unless it's a stepper motor or something, which would never be used for this cause it's too expensive and would be overkill) has to have some sort of feedback built in, or it would drift over time, or get completely off-kilter if it lost power mid-operation. so initially when you mentioned it started spinning but never stopped that's what i was thinking of, cause it seemed to have enough of the wiring and everything else to at least get going, but maybe it was just missing the feedback from the sensor to tell it when to stop. doesn't give you much to work with, cause there's all kinds of sensors that measure the angle of something like the flapper (or whatever it's called) inside the damper. at various points in this thread i've convinced myself it wasn't the sensor, then something would change and i'd think it might be the sensor after all. so anyway, i figured i might as well toss this out there now.

but yeah, their own troubleshooting guide says if the motor keeps spinning, it's a bad motor. only other thing aside from that that i can think of is the sort of generic troubleshooting process...take this damper over to a buddy's house and see if it can work on their system, etc. anyway, good luck.