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JBM HVAC
JBM HVAC, HVAC Technician
Category: HVAC
Satisfied Customers: 146
Experience:  Self Employed Air Conditioning, Heat Pump, and Gas Residential Installation/Service technician
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Worcester Bosch 30 Si 3 years old. Has blue indicator light

Customer Question

Worcester Bosch 30 Si 3 years old. Has blue indicator light flashing along with red reset button, indicating reset required. On pressing reset reverts to exactly the same condition as just described. The fan doesn't start and neither does the pump although there are the usual whirring noises as the boiler prepares itself to operate. Checked condensate drain and although it's clear now could have possibly been blocked up until just before I checked it. Pump checked and turns freely. Any ideas?
Submitted: 8 years ago.
Category: HVAC
Expert:  JBM HVAC replied 8 years ago.

Hello,

I'm going to attempt to help you out.

First i have a question for you. Was this problem an "all of the sudden problem" or was some type of was the unit worked on, manually shut off, or anything like that?

Expert:  JBM HVAC replied 8 years ago.
Another question, is this a gas or oil system?
Customer: replied 8 years ago.
It's gas.
Expert:  JBM HVAC replied 8 years ago.

Ok, i've done a little bit of research online, and i believe i may have found something that may be able to help you.

 

www.worcester-bosch.co.uk/cache/file/275/user-instructions-and-customer-care-guide--for-boilers-manufactured-from-august-2008.pdf

 

Around page 11 it talks about faults.

Customer: replied 8 years ago.
I've already done the reset bit and it just reverts back to flashing blue indicator and reset button. I'm looking for an indication of which part is at fault although I appreciate fault finding without the appliance in front of you is difficult. Could it be the PCB for instance?
Expert:  JBM HVAC replied 8 years ago.

Yes, it is difficult, but i will attempt to try. If i am not able, i will opt out and allow another expert to try and help you out.

 

Ok is there anyway you can reset the reset, so to speak?

 

Can you shut off power to the reset, does that reset it?

 

If you can get the unit to try to start and tell me what happens as its trying i should be able to help you figure out whats wrong.

Customer: replied 8 years ago.
No, switching off at the mains just gets me back to flashing reset and slow flashing blue indicator. What usually happens is the fan comes on along with the pump so I guess it's either a switch or sensor or the PCB itself. There didn't seem to be any voltage coming out of the control board to the pump although that may be because it's already in reset condition. On one occasion the pump did run briefly but there was still no fan and it still went to reset condition.
Expert:  JBM HVAC replied 8 years ago.

I see, ok. Well the Venter Motor (fan) is designed to power vent the exhaust gasses out the flue. There is a pressure switch that is activated when this fan turns on that signals the board that it can begin the ignition process.

 

However what you've described to me is that the fan isn't running currently.

 

Which could mean one of three things, the fan motor has failed, or the thermostat isn't calling for heat, or the stat is calling for heat but the board isn't letting the fan turn on(which could be due to a failed circuit board or because of the lockout)

 

Do me a favor, try and hold the reset button in for a full 60 seconds and see if this resets the system.

Expert:  alex hewitt replied 8 years ago.

Please could you let us have the light sequence on the blue light and the reset light. This is the worcester fault code.

 

Alex

Expert:  alex hewitt replied 8 years ago.

For example blue light flashing fast and no reset light or flashing slow with reset light lit.

 

Alex

Customer: replied 8 years ago.

I see what you're getting at. Would a faulty fan prevent the pump from running? Also the thermostat you mention would be the overheat, flue or limit stat rather than the room thermostat.

Blue indicator light flashes slowly..on/off every second approx.

Reset button flashes on/off apprx twice a second.

 

 

Expert:  alex hewitt replied 8 years ago.

Cool, sorry to interupt but always good to sart with the fault codes.I'll leave you in capable hands.

 

Alex

Expert:  JBM HVAC replied 8 years ago.

No problem alex, if you think you can better answer this question feel free.

 

A faulty venter motor or pressure switch would prevent the system from beginning its ignition sequence (gas valve open, ignitor initiates, ignition, flame sensor sensing flame, circulator circulation hot water)

 

As far as whether that could keep the pump from running, it really depends how the pump is wired in. If it is wired in that whenever the stat calls for heat that the circulator may start, or it may have to wait for the system to ignite.

 

If anyone of those switches you mentioned are open or faulty, it could keep the system from activating.

Customer: replied 8 years ago.
If the pressure switch is activated by the fan in order to initiate the ignition sequence then the fan may be it although looking at the fault codes the fan isn't mentioned. Thanks for the replys I appreciate it's difficult without being in front of it.
Expert:  JBM HVAC replied 8 years ago.

Well your best bet is to go with what the book says as to what the problem is. Sorry i was not able to better help you.

If you have more questions feel free to ask.

JBM HVAC, HVAC Technician
Category: HVAC
Satisfied Customers: 146
Experience: Self Employed Air Conditioning, Heat Pump, and Gas Residential Installation/Service technician
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