Onoff Posted November 23, 2020 Author Share Posted November 23, 2020 4 minutes ago, dpmiller said: Filter is a definite possibility then if it runs for a period of time- minutes or more- before locking out. The pump will happily suck the contents of the pipe until it reaches a vacuum it can't exceed. After lockout fuel seeps through the blocked filter and you get another pipeful to play with... I have had an issue a while back with the fire valve. Pretty sure I replaced this... Ditto the filter inside: I might if I'm lucky have receipts with dates and part numbers in the "boiler" file. Think it was all posted up on the eBuild forum before it went t!ts up. SWMBO messaged me to say the boiler came on fine this morning. Link to comment Share on other sites More sharing options...
trialuser Posted November 23, 2020 Share Posted November 23, 2020 I have a worcester oil condensing combi and have experienced two 9f 855 faults which the manual says is fuel supply. One was - water in the fuel. If you have recently run ouit of oil the fill of oil may have stirred up any possible layer of water at the bottom of the tank. This can then knacker the fuel pump apparently. The second fault was a blocked condensate bottle, I washed this out and all good since. Link to comment Share on other sites More sharing options...
Onoff Posted November 23, 2020 Author Share Posted November 23, 2020 12 minutes ago, trialuser said: I have a worcester oil condensing combi and have experienced two 9f 855 faults which the manual says is fuel supply. One was - water in the fuel. If you have recently run ouit of oil the fill of oil may have stirred up any possible layer of water at the bottom of the tank. This can then knacker the fuel pump apparently. The second fault was a blocked condensate bottle, I washed this out and all good since. No fault code readout on this beast! Did have a little key on the pump wear once... Link to comment Share on other sites More sharing options...
bassanclan Posted November 23, 2020 Share Posted November 23, 2020 It might be worth checking the rads to make sure they are well bled, which may be an issue if you've recently flushed it as air could cause it to cut out. Link to comment Share on other sites More sharing options...
dpmiller Posted November 23, 2020 Share Posted November 23, 2020 Just now, bassanclan said: It might be worth checking the rads to make sure they are well bled, which may be an issue if you've recently flushed it as air could cause it to cut out. how? Link to comment Share on other sites More sharing options...
bassanclan Posted November 23, 2020 Share Posted November 23, 2020 I don't know exactly how, but it happened with my oil boiler after draining it down. There may be a sensor measuring flow of water which tells it to turn off if there is insufficient. It took a £60 call out fee and 3 days of repeated radiator bleeding to get it running smoothly. Link to comment Share on other sites More sharing options...
dpmiller Posted November 23, 2020 Share Posted November 23, 2020 Not a simple oil boiler then as there's no link between burner and system other than the 'stat. Now a Combi is a different bucket of kippers... Link to comment Share on other sites More sharing options...
Onoff Posted November 29, 2020 Author Share Posted November 29, 2020 Boiler, been OK all week now playing up again. SWMBO pressed the red reset button earlier and it "hesitated" to come on. I pressed it again and it came on. Bled from the screw in the pump, no air in it. Capacitor 4uF +/- 5% is showing 3.1uF so that's a bit down. Same on two meters. Flame sensor to check still. Off to the shed to look for a capacitor. IT DOESN'T HELP I THINK I'VE BROKEN MY LITTLE TOE. NO KIDDING! KICKED A CHAIR EARLIER. ? Link to comment Share on other sites More sharing options...
ProDave Posted November 29, 2020 Share Posted November 29, 2020 The flame sensor is that black thing entering the aluminium casting top left above the capacitor. Just pull it out and look at the end, wipe any soot off the "window" in the end. It will take less time to do than it took me to type that. 1 Link to comment Share on other sites More sharing options...
dpmiller Posted November 29, 2020 Share Posted November 29, 2020 cap sounds favourite.. Link to comment Share on other sites More sharing options...
Onoff Posted November 29, 2020 Author Share Posted November 29, 2020 35 minutes ago, ProDave said: The flame sensor is that black thing entering the aluminium casting top left above the capacitor. Just pull it out and look at the end, wipe any soot off the "window" in the end. It will take less time to do than it took me to type that. That was my next question, how to remove. Will do in a while. Just put a shout out on the neighbourhood WhatsApp group and I've been for a night time limp to a neighbours who said he had his old oil boiler "next to the caravan". 4.5uF cap in that but duff. Looked in my garage and all too big /small, 80, 40, 30, 20,1 etc. (Didn't want to bugger about connecting in series). Then looked in the shed and I came up with a plastic body 4uF reading at 3.8uF (off a fridge maybe?) That's in there now albeit hanging loose and she's firing on and off like a good 'un. I don't think it's my imagination but firing up seems a bit snappier. Old one: Replacement: Now sitting with my foot in a bowl of iced water sipping hazelnut vodka for medicinal purposes! ? So that photo cell just pulls out? Two little Philip's screws on it? Link to comment Share on other sites More sharing options...
Alexphd1 Posted November 30, 2020 Share Posted November 30, 2020 First thing to check is photo cell. Just pull it out. If dirty ie smoke just give it a quick wipe and stick back in. Link to comment Share on other sites More sharing options...
Alexphd1 Posted November 30, 2020 Share Posted November 30, 2020 1 Link to comment Share on other sites More sharing options...
Onoff Posted November 30, 2020 Author Share Posted November 30, 2020 5 hours ago, Alexphd1 said: Yep, clocked that, well I followed the cable from the terminal box. The 2 screws must be for a cable clamp. Link to comment Share on other sites More sharing options...
dpmiller Posted November 30, 2020 Share Posted November 30, 2020 Yep, the photocell just pulls out. The whole control box pulls out too, with two contacts on the end to go to the electrodes (devil's work these Riellos in my book- no separate ignitor box, plus they use a tapping in the motor to derive the low-voltage supply to the control box. Makes them a mare to diagnose...) Link to comment Share on other sites More sharing options...
ProDave Posted November 30, 2020 Share Posted November 30, 2020 The cap is for the motor. As far as i know there is only one motor which runs the fan and the oil pump together. If it was the cap, then it would be obvious if the motor was running slow or not starting surely? Link to comment Share on other sites More sharing options...
Onoff Posted November 30, 2020 Author Share Posted November 30, 2020 1 minute ago, ProDave said: The cap is for the motor. As far as i know there is only one motor which runs the fan and the oil pump together. If it was the cap, then it would be obvious if the motor was running slow or not starting surely? When it wasn't working the bolier would try to start then lock out. Pressing the reset button immediately after and it would generally start. Isn't it that the failing cap had initially released what charge it had and tried to turn the motor i.e. it's on the brink of starting when it again delivers "half a charge"? Link to comment Share on other sites More sharing options...
ProDave Posted November 30, 2020 Share Posted November 30, 2020 1 minute ago, Onoff said: When it wasn't working the bolier would try to start then lock out. Pressing the reset button immediately after and it would generally start. Isn't it that the failing cap had initially released what charge it had and tried to turn the motor i.e. it's on the brink of starting when it again delivers "half a charge"? No it's not a charge storage device in this application but giving a phase shift for the second winding. the simple obvious question, when it took several presses of the button to get it going, did you hear the motor start up every time or did the motor only start the final time that it worked? Pull that bloody sensor out for a look, it only takes seconds. Link to comment Share on other sites More sharing options...
dpmiller Posted November 30, 2020 Share Posted November 30, 2020 a really "cold" start can take more juice *or* one pole of the motor is a tiny bit soft and has problems kicking the pump over (can't remember if it's a gear pump or a trochoid in the riello) But a low cap will make the motor hum and maybe turn slowly before tripping or timing out. so have you wiped the photocell yet? Link to comment Share on other sites More sharing options...
dpmiller Posted November 30, 2020 Share Posted November 30, 2020 is that an RDB? Diagnostics here, gives timing indications etc RDB 535 Fault Finding Chart.pdf 1 Link to comment Share on other sites More sharing options...
Onoff Posted November 30, 2020 Author Share Posted November 30, 2020 3 minutes ago, dpmiller said: a really "cold" start can take more juice *or* one pole of the motor is a tiny bit soft and has problems kicking the pump over (can't remember if it's a gear pump or a trochoid in the riello) That's what I was getting at. If it's already tried to start it's "nearly there". No, I'll pull the sensor first thing when I get in tonight. Link to comment Share on other sites More sharing options...
Gone West Posted November 30, 2020 Share Posted November 30, 2020 1 hour ago, dpmiller said: so have you wiped the photocell yet? 1 hour ago, Onoff said: No, I'll pull the sensor first thing when I get in tonight. Too much contact with Zoot. 1 Link to comment Share on other sites More sharing options...
Onoff Posted December 6, 2020 Author Share Posted December 6, 2020 The BiL is an old school diesel fitter by trade. He questioned whether it could be a "sticky" pump. Talking to him and he reckons one trick is to mix up a gallon of engine oil with the same amount of kerosene and pour that into the tank. This on the basis that kerosene isn't a particularly good lubricant. Saying that, touch wood, since replacing the cap (still the old fridge/freezer salvaged one) and wiping the photocell (which didn't look dirty to me) we've not had a lockout. I've a brand new Riello cap sitting here along with complete bowl filter. Could cold weather combined with a dirty filter cause lockout? Thinking in cold weather the oil is more viscous etc. Link to comment Share on other sites More sharing options...
dpmiller Posted December 6, 2020 Share Posted December 6, 2020 cupful of ash-free 2-stroke oil if you must, or a gallon of diesel. But tight pumps tend to gall and seize in a non recoverable manner... No, I'd be happy it was the cap tbh although the filter is worth a change. / you can see efficiency improvements by installing a Tigerloop, havng a constant head of pre-warmed de-aerated oil *does* work. Link to comment Share on other sites More sharing options...
Onoff Posted December 6, 2020 Author Share Posted December 6, 2020 22 minutes ago, dpmiller said: cupful of ash-free 2-stroke oil if you must, or a gallon of diesel. But tight pumps tend to gall and seize in a non recoverable manner... No, I'd be happy it was the cap tbh although the filter is worth a change. / you can see efficiency improvements by installing a Tigerloop, havng a constant head of pre-warmed de-aerated oil *does* work. Oil tank outlet is 6' - 10' above the boiler inlet. Pipe runs downhill, underground...somewhere. I always find it odd that when we run dry, after refilling, it's not a case of oil comes pi$$ing out at the bottom of the pipe(hill). I invariably have to suction it through. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now