Glow.Worm 24hxi - Cutting Out (Non "F" Fault)

[mg-max]

Chaps,

My boiler, (24hxi) is only 2 years old. Now I have noticed this AM that it is cutting out and yo-yo-ing as it reaches temperature. Even if I tune it down to 50-odd it cuts out, cools, re-starts.

I looked in the manual to see why and all it states is a "low flow" for the water. I am don;t know why this would suddenly be an issue, (or how to increase it... how do I do that?)

I have have "F" errors before, though my own error and know how to re-set the cut off valve, so it's not that.

It's not my house thermo that's broken, I checked that. (To the best of my ability)

So, my 2 questions are:

1. What could be causing a yo-yo.
2. How do I increase water flow (if needed?)

Many thanks

Max

 

[heatingman]

Is the boiler temp slowly creeping up in 2/5 deg increments, cycling on/off

 

[mrmardy]

All the advice about the pump is bunkin! READ:
The fault is with the boiler software and whats more Glowworm know this too!

Listen to what the problem is :The boiler goes to full flame for 60secs and refuses to modulate down on fire up until 60sec as elapsed! If during this initial 60secs on full flame it over shoots set point by more than 2c it will cut out.... 77c if set to 75 c say..( not pump not blocked just crap software!)

Now why does it do this after two years? Because the heat exchanger is scaling up and it cant pass on the heat as quickly into the water. Even if you get it to run for more than 60sec it will get to 75 modulate the flame (but by too much reduction!)and the temp drops (73c ish).It then puts flame back on but too high and it flies back upto 76 and modulates flame again! ( no steady modulation. It yo yo's)More often than not it will go to 77c and cut out! Now if you open up the radiators to full guess what its happy again until the system water is all hot again. (eg return water is 65c plus) so if it was pump or blocked it wouldn't run happy when cold would it now?

The only other thing is make sure you have a bypass that can dissipate enough heat and give enough flow through boiler when the TRV's all close. Preferably on Glowworms a radiator with no TRV.....( mines the one in the room with the thermostat..) An auto-bypass is all very well an good for when the zone valves are closed but you cant beat one none TRV radiator in any system!

Yes the pump can make problem worse and so can blockages. But the real problem is Glowworms crap firmware!

The solution is in the hidden settings but glowworm have to come and twiggle with these. And even then you are lucky if they send someone who knows what to do! Good luck... ( buy a decent boiler next time lol...)

 

[Dan Robinson]

You certainly are mardy.

Check the attitude at least until you have a reputation.

 

[MJGas]

Well done you sir. Replying to a 5 year old thread

 

[Dan Robinson]

Another flash in the pan smart a7se no doubt

 

[MJGas]

Did that bloke who turned up saying he was a gas lecturer ever get in the CC?

 

[Dan Robinson]

Don't think so. Imagine the car wreck that would have been when Adam and DM got to him?

 

[mrmardy]

No attitude here that needs checking. just trying to be helpful to save customers and fellow diynot's from need less expense...

ive seen change pump, flush system,change thermistors, change pcb, try turning it down....some of these things might help but the basic problems are poor modulation and glow-worm and there engineers not sorting out firmware... And ive been told that in the level 2 diagnostics /settings are some settings that can greatly help, But Gloworm dont publish these and only a hand full of there engineers know how to configure them?

Just stating some home truths about glowworm and some heating engineers who just swap this and that until they stumble onto the real problem or give up and suggest a new boiler! Im sure you know the type hey Dan?

 

[Dan Robinson]

TVR is a car mate.

Nowt wrong with glow worm.

 

[mrmardy]

TVR is a car mate.

Nowt wrong with glow worm.

No wonder Im having problems....lol I need a TRV then!

If there is nothing wrong with it how do you cure the yo yo problem?How do you alter the 60 full flame part of cycle?