Buderus gb142-30 fault code 9L 234 help

mjcotter

Buderus GB142-30 installed in 2012. 2 zones. Buderus Logamax hot water tank attached.

Currently, no hot water, no heat. Checked boiler and it was dark. Swapped out the UBA 3 fuse with the spare and the boiler booted up. It flashed P12, H7 and 9L 234.

I was able to clear the P12 and H7 by increasing the water pressure to about 15-16 psi.

I still have the 9L 234 code and nothing seems to be working. Any thoughts about what would cause this fault code?

I think I also have a crack in the condensate trap near where it attaches to boiler. It's a tough angle to get a look, but it looks like it. I was told this is a common problem with the unit.

Thankfully, it's not January! However, it is cold here in MA last night and tonight. I'm going to have a mutiny on my hands if I can't get the family hot showers soon.

Thanks for any help!!

Ironman

Code 9L 234: Faulty gas burner fitting cable connection.

It sounds like the cable to the gas valve is shorted. Could also be the valve.

mjcotter

Can I just replace that cable? If so, any chance you can point me to a part # or place online to buy? Seems like that would be an inexpensive 1st troubleshooting step. Thanks!

Ironman

I don't trouble shoot by replacing parts until I get it right. Do you have a meter that you can check the cable with? That's the proper way to do it.

I'm a Bosch/Buderus dealer, so I don't buy parts on line for them.

mjcotter

Fair enough. Found these steps. Sound about right?

8.1.19 Checking the gas control valve; Control
 Remove the casing.
 Switch off the power supply of the heating system on the circuit
breaker.
 Set the main switch on the BC10 to "1" (On).
 Start up the boiler in accordance with the “Flue gas test” menu.
See page 10 "Flue gas test" menu.
 Use a volt-ohm-multimeter to check that, while operating code
[0/l/\| is displayed, there is a voltage on the plug of the gas
control valve. The test must indicate a voltage of 20 – 24 VDC
both when testing on the central and left contacts and when
testing on the central and right contacts (see fig. 33).
 Fit the casing.

Ironman

I'd check each wire in the cable for continuity from end to end, then check each wire against the others to see if any are shorted together before doing that. Set the meter to the lowest ohm scale while doing this.

There should also be a proper ohm value for the gas valve. I'm not sure where to find that, but the valve should show some resistance and not be near 0 Ohms.

mjcotter

A buddy of a buddy stopped by today to take a look. Said his company used to install these all the time, but stopped after a few years due to issues... he removed the large unit that the gas valve, circulator, etc are all connected to and reseated it. That seemed to clear out the 9L 234 code. I was impressed at how streamlined the unit is to disassemble, nice job Buderus. The new code pointed to the ignitor (I forget the exact code). We looked at that and it was mangled pretty good, he said he'd never seen one look like that and thought that might have been what caused the UBA 3 fuse to blow. Installed new ignitor, a new condensate trap (current one was cracked) and gave it a cleaning. That seems to have done the trick. Unit starts up fine and there are no codes displayed. We have hot water! Bob, thanks for posting a reply here. I do appreciate it. I'm a computer guy, so I'm not afraid to roll up my sleeves and troubleshoot. I do like to learn about these things and the internet and Youtube in particular is great for that.

Noel

The coils in the gas valve measure (+/- 10%) left 75 Ω and right 185 Ω on a good valve. Noel

Big Ed_4

The fame sensor is though the hot surface igniter , I would replace every five years ...