GLOW WORM, NO HOT WATER

[wecda2]

HI, could anyone out there point me in the right direction to locating the fault on my combi boiler.
I have a Glow worm 24ci boiler which is 18 months old; since it was installed it has never been used as the property has been unoccupied.
Now that we need to use the boiler, I find the heating is working fine but the water at the taps just gets Luke warm.
After reading the manual I have checked the water flow rate, and checked that the inlet water restrictor is fitted, I have also checked the 3 way valve and its actuator all seem fine. Any ideas?

 

[ChrisR]

Does the boiler fire up when you open HW tap? Turn CH off while you try it.

 

[wecda2]

Hi Chris, yes the boiler fires up when i open the tap, and i have tried it with heating off.......Still the same mate!

 

[ChrisR]

Yes I thought it would be the same, need the info for diagnosis.

There's a 3 way valve which should be keeping the heat away from the radiators. Turn CH off and let it cool. Then turn tap on while feeling fat pipes under boiler. Probably one will get hot - it shouldn't.

Valve/actuator may be stuck, or burned out. Part rrp is less than £100 if you need one.

Mfrs instrs are on the net. Find the bit and whack it with a screwdriver handle - you might be lucky!

 

[wecda2]

Already had the actuator out, it looks fine and moving ok.
Flow pipe from boiler is not getting hot but just warm, i think this is just heat induction from 3 way valve...........Thanks

 

[Gas-geezer]

sounds like the flow sensor could be jammed, isolate cold water feed on boiler open hot tap remove sensor blow down sensor should spin if not replace with new sensor

 

[corgigazza]

Have had similar problems on these and solved by turning down the dhw flow rate on the bottom water inlet isolatioon valve to the correct flow rate this is also what heat call do as i called them out to a newly installed one with the same fault, to prove this run a tap at a lower flow rate, see if the water get hot

 

[wecda2]

Thanks for your suggestions, I have checked the flow sensor, that’s working fine its clean and not stuck, when I disconnect it the boiler will not fire up so must be working.
If I turn down the cold water feed the water will get hot but the flow rate drops to about 5 liters per min, hot but far to slow.
Could it be the heat exchanger? If so what would cause it to fail on a boiler that’s not old and hardly been used?...........Cheers

 

[gasman24]

hot water heat exchangers gone mate..........

 

[Gas-geezer]

Is boiler cutting out when hot tap open, if not does the burner modulate down when tap open fully if either of theses happens probably blocked plate to plate can be caused by not flushing system when installing boiler other possibility is low gas pressure should be at about 12mb flat out i think the delta t rise is 35deg so if mains supply is say 10deg the max flow rate will produce 45deg which is luke warm if say you restrict flow to 6/7 litres per min youll get hotter water boiler ok for showers but not very good for baths suggest changing to 30kw boiler for better perfomance

 

[PEDANTICVINDICTIVEMAN]

Phone glowworm technical and get ripped off at 50p a minute, not bad business idea, make shiitte boilers and then make a profit when people phone for advice.