DIYbanter - View Single Post - Potterson boiler keeps cutting out after a few minutes

marcusb3495

wrote:
Hi, this is my first post so please bear with me :-)

I have a potterson conventional boiler in my kitchen (downstairs) and a
hot water cylinder in the airing cupboard in an upstairs bedroom. I
have a control panel that sets when the h/w and c/h comes on. I have a
grundfos selectric 15/50 pump, also in the airing cupboard. Recently
this pump started making a loud whiring/vibrating noise (a bit like the
noise made by Dr Who's tardis) when the hot water came on at 6:30am
ready for baths etc. The boiler still worked, the h/w and c/h still
worked but this noise was too much to take each morning.

I turned the pump up to 3 (was on 1) to see if this would fix it but
made it worse.
I assumed, not being a plumber in any way, that it could be air stuck
in the pipes so I drained one of the upstairs radiators to see if this
would fix the problem. Needless to say it made it worse!! Now when the
h/w or c/h (or both) come on the boiler starts, the pump starts but
after a few minutes the boiler starts making a noise like it is boiling
which increases and then it cuts out (i assume this is to stop it over
heating much like a kettle).
The pump in the airing cupboard continues to work (i assume as i can
feel it vibrating and changing the speed makes it faster/slower) but
the pipes above and below it don't get hot.

Any suggestions would be very welcome before I call an engineer which
could cost an arm and a leg, and how could I enjoy my nice warm house
with only one arm and one leg?!?

i am an heating engineer--from what you have said sounds like you have
a blocked cold feed-very common this time of year--i have had 4 this
week
which means you have not enough water in system
if you take your big screw out of the pump and see no water dripping
then it proberly going to be your cold feed blocked--(if the pump is in
the airing cupboard)
also when the screw is out you be able to see or feel the pump running
just gentily poke a screwdriver in there --if theres no noise then its
your pump

a good tip ,,put your heating on occasionally in the summer --just for
minutes becuase it doesnt half help--so many people leave it off for
6months then expect that it going to work--if you didnt start your car
for 6months would u expect it to start?