Burnham Series 2 - error code STA 15 - waiting for limit to close

lbeachmike

Hi -

I have a Burnham Series 2 which is not firing on. It shows error code STA 15, "Waiting for Limit to Close"

I notice that the Gas Vent Damper GVD-6 is staying closed and I do not hear the motor at all so I think that means that it is not actuating at all.

I am a homeowner, so this is not my expertise. But the only causes I can think of is that the gas vent damper is broken, or the part that actuates the gas vent damper is broken.

Both my plumber and my heating guy are not available until at least tomorrow. Any troubleshooting steps I can pursue?

It is perhaps worth noting that last week we had a chimney company here which removed the elbow above the gas vent damper to take a look in at the condition of the liner. They also replaced the vent cap up top. But things have worked fine until today.

Thanks.

Mike

EBEBRATT-Ed

About all you can do is look at the wiring connections and see if they look ok, maybe somethin got bumped or disloged.

Otherwise yu would need an electrical test meter to troubleshoot

lbeachmike

Thanks. I don't see how electrical connections would have gotten bumped or dislodged. But what are the troubleshooting steps to determine if the gas vent damper has failed?

Is it okay/safe to put the gas vent damper in manual mode and manually turn it to the open position to see if the boiler will startup?

Jamie Hall

lbeachmike said:

Thanks. I don't see how electrical connections would have gotten bumped or dislodged. But what are the troubleshooting steps to determine if the gas vent damper has failed?

Is it okay/safe to put the gas vent damper in manual mode and manually turn it to the open position to see if the boiler will startup?

Yes

STEVEusaPA

Yes but don't leave it that way for operation.

lbeachmike

Well, the heating company came here and the result makes no sense.

The guy showed me that the spill switch had tripped.

He turned the boiler back on and reset the spill switch.

He was going to manually work the damper, but it actuated on its own. I believe he had switch it to manual mode but then switched it back to auto.

The boiler fired on, and he took put his lighter under the vent hood near where the spill switch is located and showed me that it was getting extinguished each time.

The fireplace company had just been here 10 days ago and placed a new cap up top, as well as checked down below by the furnace. They reported that the liner was in good condition and all seemed to be good.

Everything has worked normally for the last 10 days, though it's been warm, so not much heating, but our furnace does supply the hot water as well.

He removed the vent elbow to take a look directly. Things appeared to be venting normally. He reconnected it, turned the boiler back on, and now the boiler was venting correctly - no longer extinguishing his lighter.

He said we should contact the chimney company to come back and re-inspect, but I don't see how venting would work intermittently.

Obviously I now have safety and reliability concerns with no diagnosis of what was wrong.

Any ideas?

HVACNUT

The old lighter trick huh?
What's omitted is whether the flame extinguished from positive or negative pressure. 
The low volt control circuit on your boiler starts at limit, then into the vent damper. Only when the vent damper is fully open, will power continue. Out of the damper to the Rollout switch, and then through the Spill (or blocked vent) switch. From there it powers the ignition control module and and energizes the gas valve. 
So if the spill switch was tripped, the damper should have still been open, but shut off the gas valve. Unless of course someone rewired the sequence. 
Even if for some some reason the spill switch opened at the end of a cycle. Call for heat ends, burners go off, circulator stops, damper closes, a few minutes later the spill switch trips. The damper should still open on the next demand. 
Where is the boiler located and is there sufficient combustion air?
Was there excessive wind in your area at that time?
Back to the lighter trick. Time to find a new tech. Someone who has a digital combustion analyzer to check the boiler and draft.

lbeachmike

The boiler is in a good sized utility room and should have tons of air.

Yes - there actually was excessive wind in our area at the time. However, we leave by the beach and frequently have high winds - though it was especially windy. The thing that did change 10 days ago was the vent cap. That was replaced by the chimney guy - so perhaps a different style of vent cap allowing more wind down the chimney?

Re: lighter versus digital combustion analyzer - I couldn't agree with you more. It is nearly impossible to find that in my area. Nearly everything in my area by everybody of every discipline is done with the quick and dirty approach.

If the excessive wind was related to this issue, what is the solution? We've been here four years and never before had the issue, so I feel it must be associated with the vent cap change.

lbeachmike

Would testing with a digital combustion analyzer need to be done on a windy day to determine if the wind is causing an issue?

The vent is open up top. Below are the before/after photos. Even though the cap was crooked before, we had no known problems.

lbeachmike

Anybody have any ideas about this?

A local roofing supply suggested to install a standard RV metalbestos top cap on the open end of the pipe underneath the top plate of the new vent cap to prevent backdraft.