burnham in4 natural gas will not ignite


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Old 10-14-14, 08:06 AM
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burnham in4 natural gas will not ignite

Hello,
Just joined this forum, looks like some very helpful people with good info. Hope you can help me with my issue. Have a 10 yr old in4 that will not ignite this season and its getting cold.
thermostat calls for heat,, relay clicks, damper rotates 90 deg then stops then rotates another 90 degs. Then nothing. It is a intermittant spark type but I get no sparking to lite pilot. lwco seems to be working, drain down boiler until yellow light comes on the refill and light goes out. Flame roll out has continuity. Once the damper rolls final 90 degs I hear 3 clicks from micro switches on damper and have 24 at red wire that feeds the roll out and high limit on the stack then to gas valve. I understand that there are 3 steps that need to happen before it will attempt to lite.
Any ideas?
 
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Old 10-14-14, 08:44 AM
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damper rotates 90 deg then stops then rotates another 90 degs.
It sounds to me as if you are describing the damper opening, then immediately closing again...

From closed, 90 will open, then another 90 will close again.

Is the damper a Filed Control GVD ?

Is that correct?
 
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Old 10-14-14, 09:04 AM
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With the thermostat calling for heat if I turn on the service switch on the outside of the unit the damper rolls 90 deg from open to closed, pauses then rolls another 90 deg to the open position. From the description in the burnham user info says it is a "steam with probe lwco, ezsmm or ezshl" the unit does have a sv9501p honeywell gas valve and q3400a igniter.
 
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Old 10-14-14, 09:20 AM
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Looking at the diagram in the user manual it looks like the red wire from the damper runs to the frs then to the bvs then to the hsp portion of the gas valve. The red wire has 24 vac once the damper goes fully open, the frs has continuity. How does the bvs work? What I mean is does it pass full voltage if good, no voltage if bad? Should it have any resistance? Like I said the red wire has 24 vac when it comes out of the damper but only has 12 vac when it reaches the gas valve after going thru frs and bvs.
 
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Old 10-14-14, 11:28 AM
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With the thermostat calling for heat if I turn on the service switch on the outside of the unit the damper rolls 90 deg from open to closed, pauses then rolls another 90 deg to the open position.
By 'service switch' do you mean the 120VAC sometimes called 'emergency switch' for the boiler?

Why does the damper start out in the 'open' position? What you are saying is that with the boiler OFF, the damper is OPEN. Why? Was it turned off before the damper closed perhaps?

If you turn the thermostat DOWN, and the power to the boiler ON, the damper should CLOSE about 3 minutes after the burners have shut down.

At that point, if you turn the thermostat UP, the damper should OPEN. You should not see a 'double rotation'.

How does the bvs work? What I mean is does it pass full voltage if good, no voltage if bad? Should it have any resistance?
The BVS should either be OPEN or CLOSED. No resistance. If there is a red reset button on the BVS, press it to make sure it's fully engaged. Otherwise, if it has resistance, I would call it 'bad'.

BUT... how come that wire is going directly from the damper, through the two safety switches, and then to the gas valve. As I recall, that signal goes to the IGNITION CONTROL first... then the spark will light the pilot, and then when the pilot flame is proved, the Ignition Control will send 24VAC to the gas valve.

Is that not the way yours is wired?

Can you find the boiler wiring diagram on line and post a link to it please?
 
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Old 10-14-14, 11:55 AM
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It is a intermittant spark type but I get no sparking to lite pilot
OK, don't pay too much attention to my earlier post.... I just realized that you said you have the "SmartValve" which has the built-in ignitor.

In which case, yes, the wire from the safety switches will/should go to the gas valve... and you should have 24VAC all the way through that chain.

You can TEMPORARILY!!!! ( and I mean this ... TEMPORARILY!!! ) place jumpers across the safety switches to rule them out as the problem.

I said TEMPORARILY! Remove the jumpers as soon as you've proven or disproven the component.
 
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Old 10-14-14, 11:56 AM
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Correct, the emergency switch is what I meant.
The damper is in the open position until the demand come on, the unit has not fired since last spring so I am not sure what the "normal" position is when the unit shuts off after running, nothing has been changed since the install 10 yrs ago, may never have been correct.
This unit has a honeywell "smart valve" that triggers the hsp (hot surface pilot?)
According to the wiring diagram on the door of the unit the safeties are in series with the red output (24 vac) from the damper and "triggers" the gas valve to ignite the pilot.
Everything I read on this number gas valve (sv9501p2004) is that it had some problems and there is a newer, better one (sv9602p4816) that uses a stepped gas flow in addition to the pilot flow.
The bvs on mine does not have any reset, the only way I can describe it is a temp limit switch on a dryer.
Tried to attach a jpeg of the wiring but site would not let me.
 
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Old 10-14-14, 12:02 PM
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I understand what you mean by temporarily! I plan on trying to bypass bvs only as the frs showed continuity with no resistance. Should I hear anything during the ignitor process? How does it ignite? From the description of HSP(hot surface pilot) I guess the valve sends voltage to the ignitor (how much? 24 vac?) which heats up to light the pilot?
 
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Old 10-14-14, 01:04 PM
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The damper may have a problem... but it may not be preventing the boiler from starting. The dampers have several layers of 'fail safe' built in, and I believe that returning to and staying open is one of them. What may be happening is that one of the microswitches that tells the damper that it's closed has failed... and because the damper is not seeing ALL of it's "yes, I'm closed" signals, it's rotating and staying open. I'm guessing at this because I've never 'reverse engineered' the dampers to a large extent, but it would seem the logical and safe response.

You can also use your multimeter across the two terminals of the BVS. If you are seeing 24VAC out of the damper, and only 12 VAC at the gas valve, if that 12 VAC is dropping across the BVS you should be able to measure that voltage. You may in fact find the BVS is a bit warm from the resistance dissipating heat... ( IR losses )

Should I hear anything during the ignitor process? How does it ignite? From the description of HSP(hot surface pilot) I guess the valve sends voltage to the ignitor (how much? 24 vac?) which heats up to light the pilot?
If it's a Hot Surface Ignitor, you won't hear anything. Yes, voltage to the ignitor... probably 24VAC... and it has to get hot enough to ignite the gas.

This MAY be the trouble. Those Hot Surface Ignitors ( also called HSI ) have limited lifetimes. Maybe it's trying to get hot enough and can't, so the pilot is not lighting, and if the pilot does not light, the main valve won't open...

But then, you said you only see 12 VAC at the gas valve... so I dunno...

Check the BVS and see what ya got..............

By the way... the answer to your 'nickname' is " ynot? "
 
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Old 10-14-14, 01:08 PM
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Great info, Thank you!
Will test the rest tonight and try a "temp" bvs bypass, I assume an infered temp gun should pick up the igniter getting hot as long as it has 24 v going to it.
Really want to thank you for your help so far, will have more test results in the morning.
 
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Old 10-14-14, 01:19 PM
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Also wanted to mention... look closely at the BVS, that 'red button' I mentioned is quite small. You might have missed it if not looking closely.

I don't know that an infrared temp gun will be of much use. You probably won't be able to 'target' the ingnitor very well, and you're talking upwards of something like 2000 I believe. It has to get hot enough to 'flash' the gas... and that's pretty hot.
 
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Old 10-15-14, 10:23 AM
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I checked the bvs switch and it was tripped. That is one small button! After resetting it I had the full 24 vas to the smart valve. Checked for 24 vac to the ignitor and that was fine but it did not heat up. Have an ignitor on order now and will let you know how that goes.
The hillclimb ref is to an auto hillclimb series I ran in New England for many years, lots of fun!
 
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Old 10-23-14, 08:25 AM
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Installed a new ignitor and same results. Turns out I neglected to check voltage to ignitor under load, only checked it open circuit. The gas valve failed, $500 installed. Have heat and learned a lesson!
 
 

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