Gas valve controller relay logic circuit question

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My furnace is having problems and while checking out controllers, I stumbled upon a schematic. This particular furnace has relays for
controlling fans and a separate module with relays for combustion management.
The module is powered by 24v AC.
There are three SPDT relays wired like this:
http://img229.imageshack.us/img229/8329/honeywellgasctrlercz3.png
I believe the sequence of operation is: Apply power to unit Relay 1: off Relay 2: off Relay 3: on pilot valve powered through 1K1 and 3K1, igniter powered through 2K1
upon successful ignition of pilot burner as detected by flame rectification detector
Relay 1: on, open 1K1, bestow path to 2K2 Relay 2: on, turn off igniter, close 2K2 Relay 3: off, main burner enable, bestow path to 1K2
The pilot opens up, igniter cuts off, but it repeats the routine about a dozen times before it can get into step 2. If I turn off the gas at shut off, igniter continues to spark, verifying the proper operation of flame detection.
The unit is about 20 years old, so I'm guessing the NO contact 1K2 or 2K2 are pitted away and aren't making good contact fast enough before pilot valve can slam shut.
Do you guys feel that is a likely failure in a relay circuit like this?
Why bother using SPDTs to make this logic instead of using 3 N.O. SPST relays? Less contacts = increased reliability.
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snipped-for-privacy@gmail.com wrote:

I would say the flame rod is more likely to be a problem than the relays. Rod in good condition, cracked insulator, located in flame? There isn't a lot to go on.

DP relays are used to verify the relay is opening and closing - relay doesn't operate then burner will not fire. More contacts = increased safety.
You might try this at alt.home.repair
--
bud--


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