Honeywell "Smart Valve"- SV9541- test procedure to confirm it's bad?

2zones_of_fun

Hey everyone,



I'm here at the Jersey shore where it's below freezing right now and of course this is the time my 2nd floor heat decided to take a powder.  It's crazy cold outside and I'd like to get it back up and running ASAP.



I do have a different zone on the first floor that's working fine, but it's an old, not very efficient HWBB system that can barely handle that floor under the best of conditions. It can't handle the whole house.



Here's my situation: I have a Heil 90% gas forced air system for heat and AC.  The heating unit is in the attic (so below freezing right now) and the unit stopped working yesterday.



I got a trouble code on the unit of 6 flashes +1 flash which the manual says means:

Soft lockout: failed to light pilot during 90 sec. trial for ignition.



But that doesn't really match what I'm seeing.



If I cycle the main power switch so it powers up with a request for heat from the thermostat here's what it does:



Combustion blower kicks in

pilot valve opens (I can hear it) as the ignitor starts to glow

Pilot lights and the ignitor goes out. 

Pilot stays lit and then the main valve opens to kick in the main heating tubes.



They actually run for between 15 and 35 seconds but then I hear a relay kick and just as the main blower starts to turn on, flame shuts off.  The system sounds like it's trying to restart, cycling what I assume is the pilot valve.  The ignitor will glow a few times (I think 3 times for 30 seconds each with a 30 second rest in between).  Then it goes into fault mode flashing 6 times then 1 as it goes through shutting down the combustion blower.



This cycle will repeat every 5 minutes.



I think it's the 'smart valve' going but I want to confirm this.  I can see that the ignitor works and that the pilot is working as well as the flame detector by it doing all of the early stuff.

I can't figure out why it's cutting out before the main blower kicks in (or maybe just as it is trying to kick in.)



Can anyone give me a set of tests to do in order to determine if it's the SV before I lay out $350 on one to get it overnighted to me?



Thanks in advance for any help you can offer.



Mike



EDIT: Found the problem!



Thanks anyway.  I feel like an idiot.  The error code was throwing me off and making me think it had something to do with the board.



I had been working on this all day and just after I posted this I thought to check the outside drain (something I used to check all the time because it's a 90% unit, but hasn't been a problem until now).



It was frozen solid, in the attic as well as where it comes out the wall.

I got up on the roof with a heat gun and after about 7-8 minutes of aiming it at the frozen drip it started to trickle, then it started to run faster and after about 5 more minutes the water came out like a faucet.  15 feet of 3/4 PVC holds a lot of water.



Once I did that I went back up and heated the part in the attic to make sure it was clear, cranked it up and it runs fine now.



The problem was apparently caused by a backed up drain system.  There was no vacuum going through a detector that's down there by the drain so as soon as the main motor tried to kick on, the main gas solenoid would kick off.  It's a safety feature but I didn't see anything in the documentation about checking it and the code 6+1 was completely misleading.



Thanks anyway, and hopefully someone else will benefit from this post!

unclejohn

Good Job

You get a atta boy.