Old Worcester Bosch 28i junior

[Peter J Brown]

hi guys got phone call yesterday to go and look at a boiler fault, on arriving was informed that another company had been there three times in the last month. Was told that the first visit they checked all the electrical connections ie fan, air pressure switch and gas valve , the fellow said the boiler started working and the put it back together and left! It went again and they came back out and changed the air pressure switch boiler lit and they left! It went again not long after and they came back and changed the PCB boiler up and running and left,,,, for it to break down yesterday I went and checked fan and components same as they did on the first visit, tool the hoses off and blew through and the orange one had water in it. Put it back together it lit and I analysed it and put the u gauge on it all seemed great told the customer I would be back to check in the morning, to receive a phone call in the morning saying all was great and that’s the best hot water we have had! Only for to receive a phone call tonight to say boiler back off, the guy said when it’s off the red light blinks really fast and sometimes comes on itself??? Any ideas guys? Noticed the seals on the casing looked a bit worn and no sure if it an overheating issue? But would it just come back on without it being reset mmm mmm!

 

[AMGasServices]

The pumps are common.

Also check the silicone tubes from the fan to the air pressure switch. The ends go brittle to the heat.

Find the Fault finding sheet attached from the manual.

 

[Peter J Brown]

Thanks for that seemingly if you pull the red tube off and back on it works again or if you take the main casing off it works? There was a pcb fitted a few weeks ago by another company I was thinking pcb fault and fan wasn't going quick enough to activate switch but with the new board fitted kinda throws that out!

 

[Peter J Brown]

The customer says their rads and water are warmer than usual

 

[Eyes]

Is this the standard eff 28i jnr with oval lockout light/ reset button or the old 28i RSF?

 

[Peter J Brown]

The Old 28i Eyes. All points to aps but guy said it was replaced but am doubting it as the wee end that the hose goes on had a wee broken bit mmmmmmm! No sure if the company recycles old parts

 

[Eyes]

Certainly sounds like APS, haven't seen one of those in years if its the one I'm thinking of, APS is down low on RHS with common, normally open, normally closed. Would do no harm to inspect/replace silicone tubes to APS, if original will be well brittle and leaking, check venturi is clean and not melted. First relay on PCB can carbon up and give problems but this has been changed for a new one? better check relay lol, spindle on thermostat knob that goes into pot on PCB is easily broken and is possibly the cause of the high temperatures, from memory there is quite a good functional flow diagram and fault finding guide towards the end of the manual, might be worth a download, I would set a link here but am a bit of a techno phobe, don't know where to start.
Also from memory, the red light on this boiler only flashes if its electrical related, thermistor, harness, PCB, overheat reset is top left capillary type, again haven't seen one in years, would defo download manual.

 

[Peter J Brown]

Going tomorrow as I have a spare aps it's up on the left side but as you say Eyes it's an old chap no been near one in a while

 

[Eyes]

Ahhhh, Soooooo, it must be the JNR, lol, yeah, check old APS for heat distortion on the negative hose connection, PCB power to fan has possibly been dropping out causing APS to open but not in time to stop heat damage to APS over a period of time, especially if user has been constantly resetting, PCB has been changed so that should be remedied but APS defo now suspect.

 

[Peter J Brown]

As big Arnie said Eyes......Al be back

 

[Peter J Brown]

Forgot to update guys yip APS had heat distortion on the back side renewed and working

 

[sammathias]

2nd hand PCB??? I had similar fault the other week. PCB wasn't telling fan to go into 2nd speed causing it to lockout. Flames could be seen coming out from under burner into combustion chamber.