Baxi 133 HE Plus Serious problem Please HELP !!!

[baxpoti]

Is the summer/winter switch set correcttly!
All external controls demanding heat

From top to bottom
What are the 4 LEDs showing in c/h mode?
This might point you in the right direction

Have you tried disconnecting the dhw flow switch?

 

[andy1234]

Hi yes the switch is in winter mode and only the on led light shows green all the rest are off unless you turn on the water.

i have disconnected the dhw valve and still nothing

 

[baxpoti]

check that you have 230v on the terminal block all connections except first (and last)
Its not unknown for these terminal blocks to be fitted back to front.

First connection should be neutral then links for room stat and timer
So the orange and neutral should have 230v
check this with a multimeter

 

[andy1234]

ive checked all volts and they seem fine, check from pcb and to stats im just totally lost

 

[baxpoti]

Process of elimination

Disconnect room stat and timer, put the original links back in (put a live on the orange)

 

[andy1234]

yep ive disconected the stat & timer

 

[baxpoti]

Have you got 230v on the orange to earth?

Is your boiler at a high point in the system? If so

Eliminate primary flow switch

Link out the primary flow switch, black wires with a connection block just below the flow switch, disconnect the block and link the two upcoming black wires

WARNING
If it does work it may get very hot very quick
This should only be done to prove the flow switch, works or not
DO NOT leave link in place

 

[andy1234]

yes ive got 230 on orange to earth
the flow switch works fine as i put a screw drive in the connection and it lit up as you said pipes and boiler got reall hot

 

[baxpoti]

Is your boiler at a high point in the system?

You linked out the primary flow switch y/n ?
(not the dhw flow switch)
Does the boiler normally get this hot?
Was this the flow switch that was replaced?

If so (with all that you says been changed and done) I can only assume you have a 'restriction' in your flow/ return pipework.

 

[andy1234]

sorry where is the primary flow switch ?
the other day the boiler worked fine for 2-3 days, the themostate on the pipe was slightly bent and i straightened it out and the boiler worked, dont know if this was the fault as it has stopped working again.
the one with the 2 black wires & a seperate one with 2 red wires going to the stats (themostates).

so i will order these today and see if that cures the problem.

 

[baxpoti]

sorry where is the primary flow switch ?

Next to the stats

You haven't answered these;
You linked out the primary flow switch y/n ?
(not the dhw flow switch)
Was this the flow switch that was replaced?
Is your boiler at a high point in the system?

 

[andy1234]

i have linked out the primary flow switch. it was the dhw flow switch that was replaced,
not sure what you mean that is the boiler at a high point ?

 

[baxpoti]

not sure what you mean that is the boiler at a high point ?

Is it in the attic? or higher than most rads?
The primary flow switch needs testing (and probably changing as it's so intermittent). Link it out temporarily to test c/h

 

[andy1234]

the boiler is just in the garage

the central heating has started working by itself now, but stopped again this morning.

 

[baxpoti]

the boiler is just in the garage.

Another spanner in the works;
The boiler incorporates an integral frost protection feature. It will operate in both summer and winter modes. If the boiler temperature falls below 8°C (± 5°) then the boiler will fire until a temperature of 15°C (± 5°) is reached.

Get the primary flow switch changed.