Water not always heating up


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Old 12-24-09, 06:34 PM
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Water not always heating up

I have a 1999 Burnham 203nc-tei2 there are times the house feals cold i go and check the boiler the water temp is down to 60 circ. pump is running t-stat is calling for heat. i wait and watch the gauge dont go any lower so i dont know how cold the water actually goes. it will kick on heat up to 180 when its cooling off 99% of the time it fires back up around 150-160 what could be causeing the 1 percent not to fire back up when it should
 
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Old 12-25-09, 08:55 AM
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I would guess some problem with the boiler aquastat, or the wiring.

Loose wires... dirty relay contacts... bad solder connections... stuff like that is what usually causes 'intermittent' conditions.

Next time you notice the problem, try the 'tap test'. Find the 'gray boxes' that control the boiler and 'knock' on them to see if it changes something... don't wail on them of course... just kinda knock around and see if you can localize the problem.

Do you have a multimeter and know how to use it?
 
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Old 12-25-09, 11:46 AM
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Yes i do have a multimeter and know how to use it.the boxes you aretalking about are the 2 mounted on the 4" electrical box correct?
 
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Old 12-25-09, 12:35 PM
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The one I am thinking about would be your boiler AQUASTAT and would typically be about 4x6" and mounted on the boiler.

Wait... I think your boiler doesn't have an aquastat as I'm describing... but you DO have a 'limit switch'. It should be inside the front cover, at the upper left...

There are a number of other safety switches which could also be causing this to happen. And it might be that they are working correctly, and are doing what they are supposed to be doing...

There is a "Blocked Vent Switch", there is a control on the vent damper that will prevent the burner firing if the damper is not fully open, there is a "Rollout Switch", and maybe one or two others...

Do you have the manual for your boiler handy? If not, you can download a copy here:

Burnham Series 2 I&O manual PDF

Perhaps the first thing would be to check for 24VAC at the gas valve when it should be firing... This would tell you whether or not the valve is malfunctioning, or another control...
 
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Old 12-25-09, 12:43 PM
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There may also be an issue with your pilot ignitor... I think you have this... a spark ignition... NOT a 'standing' pilot... It may be that the ground connection is cruddy... these things need a PERFECT ground in order to function properly.

When the system DOES malfunction, how do you get it to work again?
 
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Old 12-25-09, 01:18 PM
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i have a standing pilot. It will start on it own eventually. I have turned the power off on back on.and that seems to help. at what tempature should should it fire back up or does it only fire back up when the t-stat calls for heat. i know the limit is set for 180.
 
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Old 12-26-09, 10:06 AM
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The 'differential' on the limit control should be around 15-20 degrees or so... so as long as the thermostat is calling for heat, the burners would/could fire up to 180, then cool to the 160-ish you mentioned, then fire again. No way should the unit cool all the way down to 60 before firing!
 
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Old 12-26-09, 12:04 PM
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Ok thanks the next time it does it i will start with testing the gas valve for 24 volts. so to say if i have 24 volts it would be the gas valve malfunctioning if i dont have have 24 volts it caused by something else
 
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Old 12-26-09, 01:03 PM
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Correct... there is a schematic in the PDF file that I posted the link to. You would then start working back, toward the 8285 relay... testing at each safety control. When you find the one that is not passing along the 24 V, you need to then determine if it's a bad component, or if it's doing it's 'safety thing' for some reason.

Let me know if you need help figuring out the schematic.
 
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Old 12-29-09, 06:08 PM
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I have isolated the problem. the vent fan is not coming on all the time. it happend to me last night and for some reason i turned up my water heater and the boiler went on i turned down the water heater the boiler went off. so after investigating further i found the have the fan spliced int the burner wires and its not get the 24 volts back all the time so all i need to do now is figure out the issue with the fan control. the 120v water heater side always works, seems to be only the 24 volt side
 
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Old 12-29-09, 07:51 PM
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the vent fan is not coming on all the time
What 'vent FAN' are you talking about?

Do you mean the motorized thing on the flue pipe (exhaust) ?
If so, that's not a FAN, it is a DAMPER. That damper CLOSES the flue pipe when the burner is off. If the exhaust flue pipe is CLOSED when the burner is firing, all of that exhaust gas is dumping into your home! This CAN and WILL KILL PEOPLE!

If that damper is not opening, and your water heater will still fire the burner with that damper closed, then something is WAY WAY BAD with your system! If you are telling me what I think you are telling me, then this situation is SO BAD that LIVES ARE IN DANGER!.

It sounds to me as if you have an INDIRECT WATER HEATER connected to your boiler system. If that is wired incorrectly and allows the burner to fire when the damper is closed, it is a SERIOUS PROBLEM! that MUST be repaired IMMEDIATELY!

CALL A SERVICE TECHNICIAN AND SHOW THEM EXACTLY WHAT YOU ARE TALKING ABOUT!

Unless I've misunderstood you... PLEASE EXPLAIN!
 
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Old 12-30-09, 04:48 AM
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it is a swg power venter run by a Model: CK-92FVP controller. its not the damper that is working fine.this fan is monted outside of the house i guess it makes sure all flue gases are sucked out
 
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Old 12-30-09, 02:56 PM
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OK, but the burner should still definitely NOT FIRE until the induced draft fan is PROVEN to be operating. Same situation exists. If that induced draft fan is NOT running, the burner should absolutely NOT fire!

Something is wired wrong... if your burner fires without the induced draft fan running when you turn up the water heater, something is badly wrong and needs to be repaired IMMEDIATELY! This is DANGEROUS! CARBON MONOXIDE WILL KILL!
 
 

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