Re: Ray Pak boiler - Hi Delta H9-1262 long w/attachment (sue me) :) - Ladder Diagrams1.pdf (0/1)

>I dont know how many, if any of you guys work on this type of stuff
> but I thought I'd share my recent experience with this boiler.
> Last week I went out on a call to a job site that I havent been to
> before. The complaint was a noisey boiler. It a fin tube type. At
> first it sounded like a flow problem, howling sound in the HX. I
> checked the flow, delta T going through the hx, and so forth. Every
> thing was ok. I then opened it up to inspect the burners and HX. If
> anyone has ever worked on this boiler you know its not an easy task
> but what I found was several cracked burners and a sooted HX. I
> replaced the bad burners and cleaned the hx. Reassemble and it ran
> sweet as pie.
> Now on to the reason for this post. After I did the repairs the owner
> wanted the CSD-1 preformed on both boilers which I did.
> When it got to checking the flame safe guard I clipped the wire going
> to the flame sensor and all three stages kept burning. At first blush
> I though it was a faulty Fenwal ignition mod. so I switched them from
> one boiler to the next. The boiler I removed it from had passes the
> test with flying colors. Switching the module had no effect and the
> flame kept burning and in fact the boiler lit without the flame sensor
> in the circuit. Not good. Not good at all. I disabled the boiler
> and told them I'd be back
> Well a week went by and today I was able to get back to it, ive been
> real busy which is a good thing. After checking the internal wiring
> and wiring to the stageing controls Ive narrowed it down to two
> things. All wiring is good. As you all know any system that uses
> rectification be it through the HSI or flame rod, the GV's should shut
> down if no flame is sensed. The module should drop out. This didnt
> happen and could be a serious problem. Imagine a bad HSI, a call for
> heat and gas dumping in. Something eventually will lite it off and it
> wont be pretty.
> In the end run I swapped out the main circuit board which has eight
> relays on it. The problem traveled to the known good boiler so its
> either in the circuit board or a relay. Tomorrow I'll figure out
> which and all will be good again. Im enclosing a ladder diagram which
> I know is a no no but oh well it beats flaming dickheads. Take a look
> and see if you can determine the problem from the ladder diagram if
> your interested. If not, carry on.
> From my point of view I think this is a serious design issue.
> Points to consider
> 1. closing of gv1 which is in the burner section that has the flame
> rod still allows gv 2 and 3 to open.
> 2. disconnecting the flame sensor still allowed it to fire and run.
> 3. closing off gv 2 and 3 and disconnecting the flame sensor allowed
> gv 1 to open and run. Eventually blower 1 shut off and blower two
> stayed on and the gv1 stayed open producing a nasty yellow flame until
> I shut it down.
> Looking at the ladder I still dont see how this is possible but thats
> what happened. I think its either a stuck relay or something is
> bridged on the board. Both boards visually looked fine.
>

>The flame sensor wire going to the module.... While running, what
>did you get for a signal?

>>The flame sensor wire going to the module.... While running, what
>>did you get for a signal?

> 11.4 ua which went to zero upon disconnecting the flame rod and all
> burners stayed lit.
> Heres what I found.
> Someone for some reason replaced K3 relay which is a dpdt 24vac coil
> with a dpdt 24vdc relay. That allowed 1st stage to fire but no other
> stages would. They then swapped K3 with K2 which is a spdt relay.
> That allowed all 3 stages to fire. Then they ran away from it. The
> problem was, it wasn't fixed and they made a potential bomb because if
> flame was lost the gv's kept open which is what I found on the CSD-1
> test. Not good.
> I replaced K3 with the proper voltage coil and put K2 in its proper
> place and all is well in boiler land.