Low/no voltage at boiler and pump connections on PCB

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Low/no voltage at boiler and pump connections on PCB

Post  mark_r on Wed Jan 08, 2014 1:11 am

Hi Guys,

I've got a problem with a Boilermate 2000. My boiler and central heating pump appear not to operate when there is a demand for heat or hot water from the central heating programmer. Having got my multimeter out I have seen that the voltage to each component at the PCB is about 2v when there a demand from the programmer. The funny thing is that if I disconnect the wiring of the component at the board and measure the voltage then I get 230v.

Would I be right in thinking the PCB is at fault or should I be looking elsewhere? I would state that I've changed the PCB on the boiler thinking this was the issue. Each of the boiler components has been checked and work.

Yours,

Mark

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Re: Low/no voltage at boiler and pump connections on PCB

Post  mike on Wed Jan 08, 2014 3:37 pm

Can you read the red bar display?
Can you read through the fault codes?
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Re: Low/no voltage at boiler and pump connections on PCB

Post  mark_r on Thu Jan 09, 2014 1:37 am

Hi Mike, do you mean the LEDs when you say the red bar display? If so all LEDs are lit when the fault occurs. Excuse my ignorance.

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Re: Low/no voltage at boiler and pump connections on PCB

Post  mike on Thu Jan 09, 2014 12:42 pm

Right well try and go through the fault codes as per the book or instructions perhaps on inside the front cover.
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Re: Low/no voltage at boiler and pump connections on PCB

Post  mark_r on Sat Jan 11, 2014 5:07 am

Morning Mike,

Thanks for the advice, this is what I have so far.

As per the instructions I turn the BM2000 off at the supply and set it to boiler mode, set the heating system room stat to full and then turn on the electrical supply to the BM2000. There is nothing shown on the display, 4 green LEDs are all lit at the bottom. These LEDs are lit regardless of their being a demand for heat/hot water at the programmer or not. If I disconnect the wiring to the heating pump or boiler I get 213V at the terminals, if connected to the components this drops to about 1V. The incoming voltage is @40V.

When switched to the emergency functions the display does not come on either. The relevant pumps run though. Interestingly I'm only getting tepid hot water and no heat when set to emergency mode, I've measured 240V at the heating element when the emergency function is set. Could this mean I have an additional issue.

Prior to moving in 3 weeks ago the house had been empty for 6 months so I'm not sure of the background to the system.


Let me know if you need more info.

Mark


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Re: Low/no voltage at boiler and pump connections on PCB

Post  mike on Sat Jan 11, 2014 10:58 am

I would check does the unit take water.
Hose on unit and drain, see if water level goes down in F & E tank.
Also use both drain off's.
Heater problem, are the fuses in? or mcb's on?
If you have no red bars on the display, then the main board has failed.
Remember you will NOT get any heating if the unit temperature drops below 60c.
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Re: Low/no voltage at boiler and pump connections on PCB

Post  Mario.S on Sat Jan 11, 2014 11:57 am

mark_r wrote:Morning Mike,

Thanks for the advice, this is what I have so far.

As per the instructions I turn the BM2000 off at the supply and set it to boiler mode, set the heating system room stat to full and then turn on the electrical supply to the BM2000. There is nothing shown on the display, 4 green LEDs are all lit at the bottom. These LEDs are lit regardless of their being a demand for heat/hot water at the programmer or not. If I disconnect the wiring to the heating pump or boiler I get 213V at the terminals, if connected to the components this drops to about 1V. The incoming voltage is @40V.

When switched to the emergency functions the display does not come on either. The relevant pumps run though. Interestingly I'm only getting tepid hot water and no heat when set to emergency mode, I've measured 240V  at the heating element when the emergency function is set. Could this mean I have an additional issue.

Prior to moving in 3 weeks ago the house had been empty for 6 months so I'm not sure of the background to the system.


Let me know if you need more info.

Mark

Sorry for the late replay
This sounds very likely , you need a new pcb. If no display showing on the pcb and all your neon are on, the processor on the pcb is crashed. The part is a GT155 Gledhill PCB.
also as Mike mentioned, check water contended in F&E tank, overflow and filling valves .
If your Boilermate has the Switch - electric backup system, you could use this temporarily, till you have the new GT155 PCB.
Hope this helps and happy new year Mario at Mario's Boiler Service

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