Worcester 28i junior- hot water but no central heating

[Sammi Brown]

Can anyone help, been attempting to fix worcester 28i junior so far fan replaced , pcb replaced, flow sensor replaced but still only have hot water and no central heating, when put on for heating pilot fires burners light but after 5-10 mins boiler cuts out.
Any ideas of which path to take next.

Thanks in advance

 

[diamondgas]

:welcome: to the forum Sammi Brown

That's one heck of an expense you've shelled out so far, is this your own appliance? When you say "cuts out", what do you mean exactly? Any flashing lights, bells or whistles?

 

[Sammi Brown]

pilot light flashes, once reset hot water still functions, problem just appears to be heating , can feel pump vibrating but my thinking is its going to vibrate even if its fault due to still trying to work,

 

[willys warmer]

Does the boiler start banging ? These boilers are only low water content so won't take long to start making noises, if so check pump has 240v, sounds like pump

 

[diamondgas]

I take it you're not over familiar with how the boiler operates sammi Brown? However if the appliance is staying alight for 5-10 minutes then you're ruling out a lot of things ... Initially thoughts are that you're describing some kind of blockage or flow restriction? Do any of the radiators warm up? What kind of temp difference do you get between the F&R pipes?

 

[dean.]

fire up in service mode, feel flow and check if the pipe is heating, if its not the diverter valve could be stuck it dhw, causing the boiler to cut out.

 

[Sammi Brown]

no banging noises , had chap look at it but he prefers problems that dont involve alot of fixing

 

[diamondgas]

no banging noises , had chap look at it but he prefers problems that dont involve alot of fixing

Get someone who can be bothered!

 

[Sammi Brown]

u r so helpful diamondgas thankyou :icon9:

 

[diamondgas]

u r so helpful diamondgas thankyou :icon9:

You're welcome

What do you mean by "pilot light flashes"? 1/sec or 4/sec ? No doubt you're aware that it makes a difference yeh?

 

[diamondgas]

Bye the way Sammi Brown .... I'll ask the question again, any radiators heating at all? Flow pipe to the radiators getting hot?

 

[Mickyplumb]

You're welcome

What do you mean by "pilot light flashes"? 1/sec or 4/sec ? No doubt you're aware that it makes a difference yeh?

If it's standard efficiency, no diverter, no sec heat exchanger either. I'm 99% sure of this.

 

[Sammi Brown]

no radiators not getting warm / hot / tepid etc

 

[Sammi Brown]

flow pipes hot, return pipes warm but will cut out in approx 4mins

 

[diamondgas]

If it's standard efficiency, no diverter, no sec heat exchanger either. I'm 99% sure of this.

You're dead right The standard eff has the flashing fault indicator/reset button Pump works for heating only yeh?

 

[zeebeedee]

Mate I'd ask on here for a Gsr engineer in your area especially if you replaced a flow switch when your heating was the bit playing up, it sounds like you have cost yourself a fortune in the completely wrong areas.

 

[diamondgas]

flow pipes hot, return pipes warm but will cut out in approx 4mins

Trying to get on the same page here Sammi Brown so forgive me When you say "cut out" do you mean flame shuts down without any fault indication?

 

[Mickyplumb]

You're dead right The standard eff has the flashing fault indicator/reset button Pump works for heating only yeh?

Spot on Diamond :wink_smile:

 

[Sammi Brown]

yes i just switched heating on ran for 4-5mins max , radiators upstairs got warm but downstairs didnt, then pilot goes out but still ignites when demand for hot water , no flashing lights

 

[zeebeedee]

You're dead right The standard eff has the flashing fault indicator/reset button Pump works for heating only yeh?

Took me ages to realise that was the reset button! :blush5:

 

[Sammi Brown]

flame shuts down, but still ignites for hot water demand

 

[Mickyplumb]

flame shuts down, but still ignites for hot water demand

I'm guessing then it's not gas lock out. If gas supply can run and keep up with hot water demand, then gas demand on heating demand should be a doddle. I think that if you remove the multiplug (CAREFULLY) from the PCB, then it will override any sensors, thermistors etc. I'm not sure how this helps diagnose but it helped me once on a junior. Let me think for 5 mins.

 

[diamondgas]

yes i just switched heating on ran for 4-5mins max , radiators upstairs got warm but downstairs didnt, then pilot goes out but still ignites when demand for hot water , no flashing lights

I'd be wanting to learn some history about your system Sammi Brown TBH! Has this just happened or been going on for a while? How long? If recent then more likely to sway towards the pump, If there's an inherent issue then system design ... Are you/have you been filling the system periodically? those kinds of things make a difference when diagnosing circulation problems. Could be a faulty pump or a blockage somewhere. Not sure if these boilers have an integral filter on the heating circuit! If they do it may be as simple as cleaning that out

If your not comfortable working on the plumbing of the boiler I'd advise getting some one else in! There's a place on here [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL] where you can request help and then check out the respondants posts etc. to get a feel of who they are

 

[Mickyplumb]

I'd be wanting to learn some history about your system Sammi Brown TBH! Has this just happened or been going on for a while? How long? If recent then more likely to sway towards the pump, If there's an inherent issue then system design ... Are you/have you been filling the system periodically? those kinds of things make a difference when diagnosing circulation problems. Could be a faulty pump or a blockage somewhere. Not sure if these boilers have an integral filter on the heating circuit! If they do it may be as simple as cleaning that out

If your not comfortable working on the plumbing of the boiler I'd advise getting some one else in! There's a place on here [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL] where you can request help and then check out the respondants posts etc. to get a feel of who they are

I'm thinking, these don't have a heating flow switch do they ? So, could it just be the pump packed up ? The upstairs rads maybe getting hot through gravitation ????

 

[Sammi Brown]

history is changed flow sensor 6 months ago as it developed a leak, other than that this problem has occured in the last month, changed fan due to it being faulty when checking initial problem , changed pcb which had some signs of problems dried cracked solder, prior to changing pcb had no hot water either but since changing pcb have ho****er now but no heating,