clicking LWCO on Bosch

kcopp

I got service call from a customer last night. Boiler I installed was a Bosch greenstar 151, 2 yrs old. Has a 24v hydrolevel lwco. Unit was locked out on D3 which signifies a low water situation.
I arrive there and there is plenty of water in the boiler and I check to see if there is a air bubble but the coin vent was spitting nothing but water out. When the boiler would try to fire up the yellow LED would flutter as the boiler would spark. I bypassed the sensor and the boiler fired up and ran perfect. Any thoughts?

Ironman

Yeah, the factory port is incorrectly placed right at TDC of the horizontal supply line and is prone to getting an air bubble in the LWCO. My rep has fussed at the factory about this since the GreenStar was brought over here, but it's fallen upon deaf ears so far. It a shame too, because the FW200 control is probably the smartest on any mod/con.

You're better off tapping in your own Tee with the bull at 9 or 3 o'clock than using the factory port. Of course, that means using a threaded LWCO.

kcopp

Thanks... odd its been working great for 2 years.

Ironman

I know, but eventually enough air gets into the LWCO and this happens. You could remove it from the port and let water trickle out and put it back on. It may work for a couple of more years, but eventually, it will happen again.

I don't know if they use the same type LWCOs in Europe that we do here and the engineers maybe haven't seen the issue over there. I think they mostly rely upon the pressure switch over there.

Empire_2

Ironman, great call and save. That's what this site is all about. Kudos to you... It's something you have seen and dealt with to rectify.


Mike T.