Hi

I have a Prima F50 boiler and have had a cycling on\off issue for the
past couple of weeks. Sometimes the boiler fires immediately, sometimes
it will take upto an hour or 2. When in the cycle phase, the fan comes
on for about 10secs before going off again

Seems to be a very common issue with this model range and probably
requires a new pcb?

However! I have noticed a second issue over the last couple of days -
with only the HW switched on, one of the radiators still gets damn hot!
All radiators are TRV equipped except the bathroom and downstairs
hallway. It is the bathroom radiator that is coming on only.

I am guessing (and it's only a guess!) that the boiler is always
heating for the time that the hot water is switched on for some reason?
- and the bathroom radiator is somehow linked into this as some sort of
overheat protection??

My timer is a 7day jobby that has seperate controls for CH & HW. CH is
definitely currently switched off

Is it possible that the pcb is responsible for both faults or could it
be something else? Your advice is much appreciated!

On Tue, 13 Jun 2006 02:54:49 -0700, hyypermonkey wrote:

Hi

I have a Prima F50 boiler and have had a cycling on\off issue for the
past couple of weeks. Sometimes the boiler fires immediately, sometimes
it will take upto an hour or 2. When in the cycle phase, the fan comes
on for about 10secs before going off again

Seems to be a very common issue with this model range and probably
requires a new pcb?

However! I have noticed a second issue over the last couple of days -
with only the HW switched on, one of the radiators still gets damn hot!
All radiators are TRV equipped except the bathroom and downstairs
hallway. It is the bathroom radiator that is coming on only.

I am guessing (and it's only a guess!) that the boiler is always
heating for the time that the hot water is switched on for some reason?
- and the bathroom radiator is somehow linked into this as some sort of
overheat protection??

My timer is a 7day jobby that has seperate controls for CH & HW. CH is
definitely currently switched off

Is it possible that the pcb is responsible for both faults or could it
be something else? Your advice is much appreciated!

Air pressure switch, pressure tubes, inlet to pressure tubes (my
favourite) or PCB.

IIRC the PCB is just a carrier for an 11 pin, 3 pole change over relay
module.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards

In message . com,
writes
Hi

I have a Prima F50 boiler and have had a cycling on\off issue for the
past couple of weeks. Sometimes the boiler fires immediately, sometimes
it will take upto an hour or 2. When in the cycle phase, the fan comes
on for about 10secs before going off again

It's either a pcb problem or an air pressure switch problem

most commonly the pcb


Seems to be a very common issue with this model range and probably
requires a new pcb?

My website www.cetltd.com


However! I have noticed a second issue over the last couple of days -
with only the HW switched on, one of the radiators still gets damn hot!
.... ...


Is it possible that the pcb is responsible for both faults

No, it sounds more like a layout / diverter valve problem



--
geoff

In message .uk, Ed
Sirett writes
On Tue, 13 Jun 2006 02:54:49 -0700, hyypermonkey wrote:

Hi

I have a Prima F50 boiler and have had a cycling on\off issue for the
past couple of weeks. Sometimes the boiler fires immediately, sometimes
it will take upto an hour or 2. When in the cycle phase, the fan comes
on for about 10secs before going off again

Seems to be a very common issue with this model range and probably
requires a new pcb?

However! I have noticed a second issue over the last couple of days -
with only the HW switched on, one of the radiators still gets damn hot!
All radiators are TRV equipped except the bathroom and downstairs
hallway. It is the bathroom radiator that is coming on only.

I am guessing (and it's only a guess!) that the boiler is always
heating for the time that the hot water is switched on for some reason?
- and the bathroom radiator is somehow linked into this as some sort of
overheat protection??

My timer is a 7day jobby that has seperate controls for CH & HW. CH is
definitely currently switched off

Is it possible that the pcb is responsible for both faults or could it
be something else? Your advice is much appreciated!

Air pressure switch, pressure tubes, inlet to pressure tubes (my
favourite) or PCB.

IIRC the PCB is just a carrier for an 11 pin, 3 pole change over relay
module.

I think you are thinking of the old Netaheat there


The Prima uses a 407677 - aka profile pcb

.... unless there's an Prima F which is different from the old Prima,
that is


--
geoff

raden wrote:
In message .uk, Ed
Sirett writes
On Tue, 13 Jun 2006 02:54:49 -0700, hyypermonkey wrote:

Hi

I have a Prima F50 boiler and have had a cycling on\off issue for the
past couple of weeks. Sometimes the boiler fires immediately, sometimes
it will take upto an hour or 2. When in the cycle phase, the fan comes
on for about 10secs before going off again

Seems to be a very common issue with this model range and probably
requires a new pcb?

However! I have noticed a second issue over the last couple of days -
with only the HW switched on, one of the radiators still gets damn hot!
All radiators are TRV equipped except the bathroom and downstairs
hallway. It is the bathroom radiator that is coming on only.

I am guessing (and it's only a guess!) that the boiler is always
heating for the time that the hot water is switched on for some reason?
- and the bathroom radiator is somehow linked into this as some sort of
overheat protection??

My timer is a 7day jobby that has seperate controls for CH & HW. CH is
definitely currently switched off

Is it possible that the pcb is responsible for both faults or could it
be something else? Your advice is much appreciated!

Air pressure switch, pressure tubes, inlet to pressure tubes (my
favourite) or PCB.

IIRC the PCB is just a carrier for an 11 pin, 3 pole change over relay
module.

I think you are thinking of the old Netaheat there


The Prima uses a 407677 - aka profile pcb

... unless there's an Prima F which is different from the old Prima,
that is


--
geoff

I've definitely got a 407677 pcb in the 50F

Thanks for the replies, i'm going to order a new pcb from geoff
intially (the boiler is in the region of 10 years old i am guessing -
previous occupants had it installed).

Seems the best way forward for me - i'm no expert on heating systems
as you can probably spot from my post

On Tue, 13 Jun 2006 20:30:17 +0000, raden wrote:

In message .uk, Ed
Sirett writes
On Tue, 13 Jun 2006 02:54:49 -0700, hyypermonkey wrote:

Hi

I have a Prima F50 boiler and have had a cycling on\off issue for the
past couple of weeks. Sometimes the boiler fires immediately, sometimes
it will take upto an hour or 2. When in the cycle phase, the fan comes
on for about 10secs before going off again

Seems to be a very common issue with this model range and probably
requires a new pcb?

However! I have noticed a second issue over the last couple of days -
with only the HW switched on, one of the radiators still gets damn hot!
All radiators are TRV equipped except the bathroom and downstairs
hallway. It is the bathroom radiator that is coming on only.

I am guessing (and it's only a guess!) that the boiler is always
heating for the time that the hot water is switched on for some reason?
- and the bathroom radiator is somehow linked into this as some sort of
overheat protection??

My timer is a 7day jobby that has seperate controls for CH & HW. CH is
definitely currently switched off

Is it possible that the pcb is responsible for both faults or could it
be something else? Your advice is much appreciated!

Air pressure switch, pressure tubes, inlet to pressure tubes (my
favourite) or PCB.

IIRC the PCB is just a carrier for an 11 pin, 3 pole change over relay
module.

I think you are thinking of the old Netaheat there


The Prima uses a 407677 - aka profile pcb

... unless there's an Prima F which is different from the old Prima,



It's a while since I saw one and I incorrectly thought it was like an
overgrown Netaheat.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards