cb 2400 solenoid

[Local4Fitter]

Just installed a new 2400. I lit it off 2 weeks ago and today I I realized that the the primary air solenoid shorted out. Dealer said it happens and will send me a new one . Having trouble controlling the boiler now. I propped the primary open with a romex staple, this had the temp up to 196 . That seemed to be too much so now I am using a thinner paper clip. I will check it in a bit. Anybody have this problem?

[AsaG]

How about swapping the high-burn solenoid in place of the bad main-air?  I'd think that should keep you up and running until you get the replacement.     

[boilerman101]

Having operated a E2400 for 2 seasons, I would say your best option is to swap the secondary low solenoid (lower left) and put it into the primary (upper left) position...Then just prop that secondary low solenoid open 1/4 inch or so. It is a smaller cover and should not cause your Eclassic to overheat until you get the new solenoid. The secondary high solenoid which allows more air in any way will then operate normally and allow a high burn. I would not hook up the power lead to bad solenoid now in the new secondary low position or you could blow the fuse.

[Local4Fitter]

Thanks guys, I was lying in bed this morning thinking of doing the very same thing you guys wrote. Yesterday I propped the primary open with a romex staple but it was too much( water temp 196). I then put in a paper clip that ended up falling out (didn't open the paper clip) fire out this morning. The wood relit in under a minute with a propane weed burner. Heading out to do the switch now.  Thanks again, Doug

[Local4Fitter]

Well, I swithched the high burn solenoid with the bad main solenoid. When I turned the power on the main solenoid started to chatter and when it did pop open it just started buzzing. This is probably why it burnt out in the first place. When I first realized there was an issue and the breaker had popped I opened the air box and touched all 3 solenoids. The Main one burned the back of my hand. Could this be a controller issue?

[AsaG]

When I first restore power to mine, the solenoids don't really chatter; it's more like a single 'clunk' with all three in unison.  When the controller calls for them, they will, on occasion, produce a louder hum than normal but still no chatter.  How fast did the solenoid get hot to the touch? 

It's possible a bad controller can cause solenoid failure if the controller driver circuitry is damaged.  An AC solid state switch contains two components.  One passes current on the positive half-cycle and the other on the negative half-cycle.  If either is damaged and not passing current when they are supposed to, the load (120V AC solenoid) receives a DC half-wave rectified supply.  Coils designed for an AC supply don't play nicely with, what amounts to, a pulsed DC supply.

In order to avoid boring the entire forum with electrical drivel, I found this basic explanation.  While it talks about 24 volt relays and solenoids, the same holds true for all voltages.

"Ac coils for relays and soleniods have a shader ring(usually made of copper)on the top of the core. Because of the shader ring, the magnetism developed in part of the core lags somwhat the magnetism of the remainder of the core. That is, there is a slight phase displacement between the magnetism of the part of the core and the remainder of the core. Thus, as the unshaded-core magnetic energy decrease to zero every half-cycle, the magnetic energy still present in the shaded portion of the core holds the armature sealed. By the time the energy in the shaded portion decrease to zero, coil and unshaded-core magnetic energy have begun to increase once again as current increase in value.

Applying AC to a dc coil will cause the coil to hum and if it is a relay it will chatter. The resistance of a DC coil is about 4 times the resistance for an AC coil for the same voltage.

>AC coils have inductive reactance in addition to the coil resistance that affects the coil current. The AC current for a 24V AC coil is about double the DC current for a 24V DC coil.

Operating a 24V AC coil on 24V DC could cause the coil to fail as the current would be too great. The current would be very close to 4 times the current for 24V DC coil."

Source: http://forum.allaboutcircuits.com/showthread.php?t=31610 post #4

[Local4Fitter]

I'm not sure how long it took to get hot. I heard what I thought was the end of a cycle and just being curious I walked over to check the temps and the screen was blank, the breaker was tripped and the solenoid was hot enough to burn skin. The solenoid may have been chattering or buzzing for some time before the breaker tripped.

[AsaG]

Sounds like you have a controller and new solenoids in your future.  Not sure how cold it is where you are but, here in Minnesota, there is no way those solenoids would be burn-your-skin hot under normal circumstances.  What strikes me as strange is the breaker tripping.  My stove has a fuse holder near the power switch on the air-box with, I believe, a 5-amp fast acting fuse.  It would be almost impossible for a typical 15 or 20 amp circuit breaker to trip faster than a type AGC fuse would open. The fault current available through this size and type of fuse would be less than ~60A for less then 1 cycle.  60A over 1 cycle is well below the threshold where a typical thermal/magnetic household 15A breaker will trip.  By comparison, a typical 10A window A/C can easily draw 50A+ over a few seconds at start-up.  Is the fuse blown?  Does your breaker include GFCI protection (test button near the handle)?

[Local4Fitter]

AsaG, maybe I wasn't very clear. The breaker that tripped wasn't the 20A in the panel in my house. It was on the boiler itself. I have a 2012 e-2400. The on/off switch is the breaker or maybe more of a gfci. There are no fuses on my stove.

[AsaG]

Ahh, CB did away with the fuse and went with a circuit breaker/switch with similar trip characteristics of the fuse it replaced. Makes perfect sense now!  In that case, I'd say the control failed and took the solenoid with it.  There is a possibility the breaker tripped before permanent damage was done to the solenoid(s) but I'd replace them to be on the safe side.  Sorry about the misunderstanding!  say_what

[beenthere]

AsaG, maybe I wasn't very clear. The breaker that tripped wasn't the 20A in the panel in my house. It was on the boiler itself. I have a 2012 e-2400. The on/off switch is the breaker or maybe more of a gfci. There are no fuses on my stove.

If Ground Fault Circuit Interupter, then you may just have a ground fault problem. They are not circuit breakers protecting an overload. They trip the circuit when there is an imbalance between the hot and common lines.
Would be good to determine just which it is.  That would help a lot in tracking down your problem, I'd think. ;)

[boilerman101]

Sounds like the controller is bad. I spoke to my dealer buddy and here is his trouble shoot process for this issue.
Shut down the power on the controller, reset breaker, check for low voltage power at the shuttering solenoid with Firestar powered off.
If any power is present, it confirms controller has gone bad. Probably sending low voltage to solenoid and that is what is frying it.

[Local4Fitter]

Thanks boilerman, just went out and did the trouble shoot. I'm not sure if I am using this multimeter correctly. I only use it to check temps on pizza oven. Anyway I checked the voltage with the controller power on and calling for primary air (118v) I then checked with controller on and no call for air (primary solenoid had 16v, secondary had 0.0, stage 3 had 0.0). I then shut off the power at the firestar controller (primary solenoid had 16v, secondary 0.0, stage 3  0.0) . I just got off the phone with dealer, he said he will e-mail the trouble shooting process. I told him my findings and he said sounds like I need a new controller. I may have the controller and solenoid tonight.

[Local4Fitter]

My dealer doesn't have the controller in stock after all. I won't see it for 3-4 days he said. I guess CB doesn't overnight packages. Good thing its not really cold yet. Boilerman's trouble shooting instructions were alot simpler than the official CB instructions my dealer e-mailed to me. With the same end result.

[sam-tip]

My E3200 did something similar.  It kept blowing the switch/breaker.  One of my solenoid shorted out and tripping the breaker/switch.  I am getting 0 volts AC at the solenoid connection and 160 Volts DC.  All without the wire connected to the solenoid.  It is the solenoid on the low secondary air.  Seem to run fine if I just leave it unhooked.  Replaced the solenoid but unhooked it because I was thought the 160 Volt DC would burn the solenoid out.  Plus it was staying open 100% of the time.

Waiting for dealer to figure out it is the controler.

These are the instructions the dealer sent me.

They said you need to turn power off to the stove at the breaker and test the following items for ohms.  Test the (2) terminals on each solenoid, ohms should be between 15-30ohms, if not within this range replace the solenoid, if in range.  Test the (2) terminals at the transformer, ohms should be between 15-30 ohms, if not replace the transformer. If in range disconnect the red 24-volt wire from the transformer. Test the transformers resistance, it should be between 0.8-1.3 ohms. If not then test the LED lights by removing the 2 screws and unplugging them there are (3) total one on each side in the roof and on the interior of the door, they should have at least 1,000 ohms each, if less than 1,000 ohms replace that light.  If in that range disconnect the 110-volt wires from the fan and test the fan for ohms, should have between 5-10 ohms.  If not in that range replace fan, if in range then reconnect everything and restore power to the stove at the breaker and turn power on at the Firestar control.  Test the transformer by touching the meter leads to the terminals on the transformer. Each solenoid should have have at least 110 volts going to the terminals with the power on and the door open.  If not the controller may be bad.  If everything is within range let me know and we will have to go from there.  Please make sure the meter is in ohms Ω with this symbol and also make sure the meter is capable of reading over 1,000 ohms as many are not.  Everything on the boiler operates on A/C there is no D/C. 

[boilerman101]

You are checking for AC voltage. Why are you checking with meter on DC at that point?
Re-read my post above. With power to the furnace and with the firestar powered off, check for low AC voltage at the solenoids, particularly the solenoid that has failed. There should be none. If you are getting any low AC voltage at that time, it is probably the firestar. Otherwise perhaps you just had a solenoid fail at random.

[sam-tip]

There was no AC so I switched my fluke to DC to check if there was any DC.  There was. There had to be some kind of voltage blowing the switch/breaker.  The DC was activating the solenoid and the solenoids are not meant to run on DC.  So I blew my spare solenoid with the DC voltage.   Its a educated guess that a triac is used to control the solenoids.  If one of the diodes in the triac blows in the triac it could act as rectifier turning AC to DC. But I would need a scope to know.

[AsaG]

There was no AC so I switched my fluke to DC to check if there was any DC.  There was. There had to be some kind of voltage blowing the switch/breaker.  The DC was activating the solenoid and the solenoids are not meant to run on DC.  So I blew my spare solenoid with the DC voltage.   Its a educated guess that a triac is used to control the solenoids. If one of the diodes in the triac blows in the triac it could act as rectifier turning AC to DC. But I would need a scope to know.

Yes Sir, according to my Fluke scopemeter the failed controller I looked at was sending half-wave rectified with ~1.7V 'tail' below zero-crossing to the solenoid.   Tried to explain it earlier but failed and gave up.  There have been quite a few reports of these failing in this manor.  Hopefully they do a re-design on the output switching circuit(s).