Riello BF5 Post Purge Venting getting stuck

Jakey25

Hello,
I have a Riello BF5 burner on my boiler. It is a PB Direct Vent boiler. The issue I am having is it is getting stuck in Post Purge. This is causing the water in the boiler to cool, and prevents the burner from firing. It happens randomly. This metal "clapper" on the aqua-stat is what is getting stuck. I have to kill the power to the boiler to reset everything, and it fires right up when I turn the power back on.
There is this ICM AL 1009 board on my burner. From what I have been able to find online, it is sold as part of a Post Purge Vent kit and has a part number from Riello (C5830010). It states this replaces the ICM 1008 board that comes with the burner. When I search for a replacement 1009 board I can not find anything. I can not cross reference the relay either. My guess is either the board or the relay is failing and causing this to post purge issue to happen. Anyone know if there is a new board or relay that replaces this one? Thank you in advance for any help and direction.

Jamie Hall

I see three different things circled. Which is it you're after?

Jakey25

The things that are circled are the metal clapper that is getting stuck and I circled the 2 part numbers I mentioned in the thread. The AL 1009 and the relay. I can not find either part or a cross reference for either to replace them.

Jamie Hall

The metal clapper to which you refer is, I presume, the relay in the centre picture? If so, that's a pretty plain vanilla relay, though I can't tell whether it is plug mount or hard wired, nor what contact sets are in use.

Jakey25

If you are seeing the pictures in the same order as me, the clapper is on the last picture. It says Honeywell on it. The clear box is the relay on the AL 1009 circuit board. I tried search that name and number on it and could not find anything. I did the same for the AL 1009. All this stuff was installed in 2010, so I am guessing it has been updated by now.

Jamie Hall

Not surprised you couldn't find that specific relay -- cheap Chinese component. Dive a dozen, and failure prone.

I have no idea what the "clapper" is -- that is not a term in technical use. It is not, however, part of the circuit board, so it seems unlikely that replacing the board would affect it much. It looks to be related in some way to the aquastat.

STEVEusaPA

Can’t seem to add the manual from my iPad.
The Kit Part Number is C7001084

Jakey25

Correct, the metal piece that I am call a clapper that says Honeywell part is on the aqua-stat control. When the blower is not running, that is pulled in. When the blower kicks on in pre or post purge, that is pulled out. This AL1009 board and relay are attached below the burner under the case. It is wired into the primary control of the burner, on those pins. Those 2 items are what is controlling the post purge. I am guessing that the Relay or something on that board are not telling the metal piece on the Stat to close and turn off the blower and that is why it is getting stuck. Where this stuff is older now, I am hoping you or someone who has installed these BF5 burners would know if this board/relay failing would be causing this and what the new parts are that have replaces these older one.

HVACNUT

Jakey25 said:

Correct, the metal piece that I am call a clapper that says Honeywell part is on the aqua-stat control. When the blower is not running, that is pulled in. When the blower kicks on in pre or post purge, that is pulled out. 

Meaning, when the blower (burner motor only) is not running, the clapper (relay) is pulled in?

That relay (clapper) is ONLY energized when TT is closed. It sends power to B1 and C1, as long as boiler temperature is below the limit setting for B1 and above the Low setting for C1.

The post purge timer is constantly powered before the limit. Limit (B1) goes to L on the Riello sub base.Disconnect TT from the aquastat, raise the Hi to 200° and the Lo to 180° and see what happens. 

It looks like ZR,ZC are being used as well, so turn down any other thermostats while checking.