Glow worm 30 CXI F5 fault **Solved**

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Glow worm 30 CXI

Writting this up to help others.

TLDR/Summary (Failing relay on control board, controlling power to pump, causing overheat, F5 fault to be displayed)

F5 fault was being displayed on the boiler.

The system was 10 years old, no filters fitted, inhibitor added to the system ~5 years ago. 10 radiators, 2 trvs seemed to be stuck, no bypass radiator as we may
have fitted a trv to one 5 years ago(oops?). Boiler located 1st floor, radiators and shower located on ground floor . ( Second combi boiler is fitted adjacent )

Plumber 1 who did the yearly gas certficiate was unable to come. but suggested to bleed the rads. (done)

System was then cleaned with x800 (1.5 hours)
Plumber 2 said it was likly the small plate to plate heat exchanger, the cost to clean or replace (including labour was similar), this was replaced, other checked were carried out, including pump. Water seemed to be hotter quicker)
system ran fine for a day before presenting f5 fault.

System washed out using filling loop
X800 added for 2.5 days, only 1 day the sytem was running

Thermisters were checked with a multimeter, giving values of 10.89, 11.13k Ohms reducing to 2.93 when hot. (lower values when getting hotter)

Note the system overheating was never observed after reseting the thermal cutout (little red button on the top left pipe you have to press)

After next fault F5 was presented, boiler reset. "Kettling" was now heard from the boiler, plubmer now suggested replacing the main heat exchanger. A full Recondtioned unit on ebay was £70.
This was fitted after some delay. Removed one did not appear to be blocked. Pump working fine, hot water and heating again working well.

F5 presented after a day, all thermisters and diverter head swapped with adjacent boiler to aliminate any issues here.

Boiler power was reduced, as it was on max (on board it says Eco) , this is done by adjusting the pot on the little board.
Rest worked fine

next day (not sure exact order of events)
F5 again, reset and kettling again !? pump opened and did not appear to be turning, screw driver inserted and it started.

Pumps capictor was checked and its value was only half (911.6) of what was written on capacitor , other boilers pump was even lower (802.3 instead of 2,500 (2.5uF)). Motor widings
were checked and their resistence were similar and within spec (168.9 and 181.6 ohms) (not replaced yet as don't know where to obtain them from, RS components sell similar)

next day
F5/ reset
Pump not moving (gas turned off btw) no voltage reading being presented at pump side. (F1 would eventually come on and is reset by powering off and on)


(Plumber suggested swapping control boards)

Control board, no voltage at connector ( connector cover comes off exposing contacts) pump appeared to come on (can't obesrve as bleed screw needs to be closed due to circuit board being live) the relay can be heard clicking on and off and on. ( Using a multimeter here must be taken with caution)

Boards swapped and now other boilers pump is not running.

Switched back and control board replaced

Diagnosis, faulty relay which was on its way out was stopping the pump from running, intermittenly , when the pump was tested it always worked. When it did not work, pipe work was overheating and the safety stat was kicking in

notes
The D.H.W cold inlet filter was replaced as it was brittle (put washer in first or use suitable lubricant),C.H return heating filter was cleaned and carefully put back (orientation is important)
Magnaclean filters were fitted to both boilers

The replacement board was a board that had died previoulsy and was repaired by replacing a majority of the capacitors on the board with higher rated ones).
Replacement boards are available from around £40+ but ensure they are actually refurbished not just removed from an old boiler)
 
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Great update.

Is "it needs a new H/X" now a standard greeting from a plumber?
 
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DP

Joined
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Country
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Glow worm 30 CXI

Writting this up to help others.

TLDR/Summary (Failing relay on control board, controlling power to pump, causing overheat, F5 fault to be displayed)

F5 fault was being displayed on the boiler.

The system was 10 years old, no filters fitted, inhibitor added to the system ~5 years ago. 10 radiators, 2 trvs seemed to be stuck, no bypass radiator as we may
have fitted a trv to one 5 years ago(oops?). Boiler located 1st floor, radiators and shower located on ground floor . ( Second combi boiler is fitted adjacent )

Plumber 1 who did the yearly gas certficiate was unable to come. but suggested to bleed the rads. (done)

System was then cleaned with x800 (1.5 hours)
Plumber 2 said it was likly the small plate to plate heat exchanger, the cost to clean or replace (including labour was similar), this was replaced, other checked were carried out, including pump. Water seemed to be hotter quicker)
system ran fine for a day before presenting f5 fault.

System washed out using filling loop
X800 added for 2.5 days, only 1 day the sytem was running

Thermisters were checked with a multimeter, giving values of 10.89, 11.13k Ohms reducing to 2.93 when hot. (lower values when getting hotter)

Note the system overheating was never observed after reseting the thermal cutout (little red button on the top left pipe you have to press)

After next fault F5 was presented, boiler reset. "Kettling" was now heard from the boiler, plubmer now suggested replacing the main heat exchanger. A full Recondtioned unit on ebay was £70.
This was fitted after some delay. Removed one did not appear to be blocked. Pump working fine, hot water and heating again working well.

F5 presented after a day, all thermisters and diverter head swapped with adjacent boiler to aliminate any issues here.

Boiler power was reduced, as it was on max (on board it says Eco) , this is done by adjusting the pot on the little board.
Rest worked fine

next day (not sure exact order of events)
F5 again, reset and kettling again !? pump opened and did not appear to be turning, screw driver inserted and it started.

Pumps capictor was checked and its value was only half (911.6) of what was written on capacitor , other boilers pump was even lower (802.3 instead of 2,500 (2.5uF)). Motor widings
were checked and their resistence were similar and within spec (168.9 and 181.6 ohms) (not replaced yet as don't know where to obtain them from, RS components sell similar)

next day
F5/ reset
Pump not moving (gas turned off btw) no voltage reading being presented at pump side. (F1 would eventually come on and is reset by powering off and on)


(Plumber suggested swapping control boards)

Control board, no voltage at connector ( connector cover comes off exposing contacts) pump appeared to come on (can't obesrve as bleed screw needs to be closed due to circuit board being live) the relay can be heard clicking on and off and on. ( Using a multimeter here must be taken with caution)

Boards swapped and now other boilers pump is not running.

Switched back and control board replaced

Diagnosis, faulty relay which was on its way out was stopping the pump from running, intermittenly , when the pump was tested it always worked. When it did not work, pipe work was overheating and the safety stat was kicking in

notes
The D.H.W cold inlet filter was replaced as it was brittle (put washer in first or use suitable lubricant),C.H return heating filter was cleaned and carefully put back (orientation is important)
Magnaclean filters were fitted to both boilers

The replacement board was a board that had died previoulsy and was repaired by replacing a majority of the capacitors on the board with higher rated ones).
Replacement boards are available from around £40+ but ensure they are actually refurbished not just removed from an old boiler)

Issue is X800. Great chemical, works wonders. Also kills pump if the jungle juice is not flushed out of the system completely. This is often overlooked. Have seen results of this. Often chemical cleaning is rushed. Do it the way manufacturers recommend will take time.

Have used X800 often, no issues.
 
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