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Ask Andrew Smith Your Own Question
Andrew Smith
Andrew Smith, HVAC Technician
Category: HVAC
Satisfied Customers: 3623
Experience:  City & Guilds Plumbing and Heating Engineer
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I need help I have an a high flow 400 electronic The worst

Customer Question

Hi I need help I have an a high flow 400 electronic
The worst for wear it was leaking from the manifolds but has now stopped , I have checked stats , red light is flashing fast can you help as can't afford to replace
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Welcome! We keep going until you have all of the information you need.[b/]. Extensive training & coaching also available.

Tell me a bit about your technical background please so that I can coach you appropriately

This is might well be nothing that you will be able repair yourself or simply push a reset button to get going again.

It will most likely need to be seen by a professional Worcester technician.

If you can tell me which direction you are from the center of the nearest city I can look for a well rated service outfit in your area.

.We can go from there if you wish.

Customer: replied 1 year ago.
I'm an electrician and I won't be calling Worcester engineers hence the reason for asking on here
Customer: replied 1 year ago.
Relist: I still need help.
Expert:  Andrew Smith replied 1 year ago.
Hi my name is ***** ***** I will try and sort your problem in the shortest possible time.
Ok, tell me what happens when you reset the boiler.
Any noise - fan whirring, clicks, etc and how long before the red light comes on?
Customer: replied 1 year ago.
Yep click from boiler and whirring noise
Customer: replied 1 year ago.
Red light flashing fast on central heating , no light on hot water
I know I need to change a few bits ie diverted valve. And have a spare
Already tried another circuit board
Expert:  Andrew Smith replied 1 year ago.
Ok, does it get start ticking?
Or just the fan, a 5 second delay and then flashing light?
Customer: replied 1 year ago.
Yep 5?second delay no ticking
Sorry trying to sort my boys out
Expert:  Andrew Smith replied 1 year ago.
Ok, sounds like a problem with your air presure switch.
Do you want to take the cove off and we can go through it together?
Expert:  Andrew Smith replied 1 year ago.
Can you confirm this is the model you have, as they have made a few with the same name;
https://www.worcester-bosch.co.uk/cache/file/174/installation-and-servicing-instructions-for-highflow-400-electronic-rsf--discontinued-march-06.pdf
Customer: replied 1 year ago.
Yes electronic one
Expert:  Andrew Smith replied 1 year ago.
ok good.
Are you able to take the outer case off?
If so then reset the boiler and tell me if you see the fan running?
If you do turn it off and give a good squirt of wd40 on the spindle to see if we can make it spin faster.
Let me know what you find
Customer: replied 1 year ago.
Fan impeller at the top not spinningAnd cover off ?
Expert:  Andrew Smith replied 1 year ago.
Ok, can you check power to the fan?
Check L and N, both against Earth and each other
Customer: replied 1 year ago.
Will do in 30 mins
Expert:  Andrew Smith replied 1 year ago.
No problem - come back to me when you have
Customer: replied 1 year ago.
No power to fan
Expert:  Andrew Smith replied 1 year ago.
Ok, the power comes straight from the PCB - can you check for power there and hopefully it is a defective APS not closing or the cabling to the fan
Customer: replied 1 year ago.
Just to not I think the expansion vessel diaphragm has gone as well
Yes that's where I checked there's also no voltage on the aps terminals
Unless there volt free
Expert:  Andrew Smith replied 1 year ago.
No should be 240V
Does the pressure rise excessively when heating?
Customer: replied 1 year ago.
No voltage there mate
Expert:  Andrew Smith replied 1 year ago.
I sent you the link for the manual, you should download it.
There is a wiring diagram and a fault finding chart.
Let me know if you need help, but to be honest I would just be repeating what is in the manual
Customer: replied 1 year ago.
Where so that's it is it
Expert:  Andrew Smith replied 1 year ago.
Ok, we can go through it together if you wish.
Page 49 - do you have power both sides of fuse 1?
Expert:  Andrew Smith replied 1 year ago.
Do you have time to go through the fault finding together, but you will need a mutlimeter
Customer: replied 1 year ago.
Yes please I have oneReady when you are
Expert:  Andrew Smith replied 1 year ago.
Can you take the cover off and expose the PCB.
Firstly check power each side of Fuse 1
Let me know what you find
Customer: replied 1 year ago.
Yep done
Expert:  Andrew Smith replied 1 year ago.
Do you have power both sides of F1?
If so then check power both sides of F2
Let me know what you find
Customer: replied 1 year ago.
Fuses are fine
Power both ends of both
Customer: replied 1 year ago.
Fuses are fine
Power on both ends of f1
Nothing at f2
Expert:  Andrew Smith replied 1 year ago.
ok, i need to know what the lights are doing;
The green power light, the hot water light and the central heating light?
Customer: replied 1 year ago.
Central heating light flashing fast
No light on hot water
Expert:  Andrew Smith replied 1 year ago.
ok, pointing to a sensor fault;
Visually inspect all three temperature sensors on the appliance (combustion chamber cover needs to be removed to see the central heating / primary sensor). Are they electrically connected and look o.k. ?
Customer: replied 1 year ago.
Looks like the G3 thermostat is faulty as
Pulled cable off and the lights have changed to alternate flashing on ch and hw
Expert:  Andrew Smith replied 1 year ago.
That's good, it should only cost about £25 to swap it, but you will need to drain the boiler to do it.
Customer: replied 1 year ago.
Is there a way to test the boiler without it
As it's open circuit won't it run without it or is it monitored ie resistance
Expert:  Andrew Smith replied 1 year ago.
It is a thermal resistor, so the boiler needs the resistance to be between certain criteria for the PCB to know the temperature.
You should be able to get one tomorrow if you call your local Parts Center in the morning.
Customer: replied 1 year ago.
Cool thank you
Expert:  Andrew Smith replied 1 year ago.
No problem - come back if you need me again