Glow Worm Boiler Problem - SOLVED! Seized 3-port valve.

SaabmanBOF

SaabmanBOF

SaabmanBOF

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Good morning everybody. I have a problem with my Glow Worm Flexicom 18 SX; it only fires up if the hot water circuit is also calling for heat. Once fired up, the rads heat up as normal, until the hot water is up to temp, when it shuts down. Pressing the minus button for five seconds brings up codes 5 and 30, neither of which is in the decode list.

Is this something I can fix myself, or (probably...) is it time to send for a pro?
 
F5 is a overheat fault but it didn't list 30.

By the way I googled Glow worm Flexicom 18 SX fault codes 5 and 30
 
Thank you for that; I should have been more exact. The problem doesn't seem to be an overheat malfunction, though. I don't get F5 or F30 displayed, just the figure 5 then the figure 30, alternating, and the boiler isn't actually locking out; if I turn up the temperature on the hot water 'stat on the tank, it fires up and runs OK. If I was using lots of hot water, I might never have known I had a problem at all...
 
Are you sure? The problem isn't with the distribution of the circulating water, it's that unless the hot water cylinder is calling for heat, the boiler does not fire at all. I can't see how the motorised valve would affect that.
 
You've already said you don't get error codes, just status codes. The hot water side works and operates the boiler, you can get heat into the radiators at this time which indicates the 2port or 3port has operated or part operated, but not made the electrical switch to signal the boiler to operate.

Mick
 
Motorised valves have permanent power from the spur switch. It's the valve or valves that signal the boiler to run, not the clock or thermostat. Unless you have a combi.(Which you don't) ;)

Mick
 
NOW I understand! Thank you again.

It's a Honeywell 40004805-001, a 3-port.

There's no sound of movement within it when I turn the boiler power on or off; I've given it a few sharp taps with a hammer, but that made no difference. It makes no difference whether the control lever is set to auto or manual, either. I guess I should just go ahead and replace it?
 
Honeywell are quite reliable, it's probably just the synchron motor that's not opening the valve (heating) enough to activate the microswitch. The motor is replaceable.
http://amzn.eu/d/4r93YNF

Edit: above link is from a very quick search, you can pick them up from screwfix, b&q, wickes etc.

Mick
 
Thank you again; that is very helpful. I presume actual replacement of the motor is quite straightforward, but can I easily remove the silver box from the valve assembly with the valve assembly in situ, or will I need to have the whole thing on the bench?

STOP Press: Found it on line. Easy Peasy... I have the lid off, and the round motor casing is very hot, so I presume it has seized. I'll sort it as soon as I get a new motor.

Note to self: remember to turn off the power to the boiler before doing the job...
 
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Motor replacement can be done without removing the head. You need to kill the power though, and be able to crimp connect two wires, polarity doesn't matter.
If access is poor, then you can remove the head (two diagonal torx screws) but only if there is NOT a red gasket in place between the hydraulic valve and motor head.
Removing the motor normally is one tiny screw and slightly rotating the motor to unlock it's position.
 
I have replaced the synchron motor (awkward for access, but very easy otherwise). It still doesn't work. ******! There is a slight change, in that if I select central heating only, the pump runs for about half a second, then cuts out. All else is as before; I still have no F codes. Double ******!!

Where should I look next, or should I give up and send for an engineer?
 
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Synchron motors are the common reasons for valves not operating the heating. The pump energizing could just be a test signal from the boiler. To test any further you need a multimeter and some basic skills in operating one, to test the heating circuit. If you're not sure about doing that, then yeah get a professional out m8.

Mick
 
No need, thank goodness. It must have found out I was threatening it with a multimeter; I tried it again an hour later, and now it is working normally again! Let's hope it keeps doing so...

Thank you again.
 
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