no central heating or hot water

[mug51]

hey,

i have recently replaced a blocked pipe in my system (out pipe from towel radiator).
i have since filled up the system to 1 bar and i am getting no heating or hot water. what happens is when i turn on the hot water tap with ch on, the pressure goes up, and ignition light cuts off then pressure falls back.

ive tried bleeding all the radiators but no luck and ive tried unscrewing the auto air vent with no solution.

could you guys please help?

edit: its a combi boiler, worcester 24cdi

 

[glasgowgas]

have you vented the pump as well??

switch off combi, remove central screw from pump ( a tea towel underneath pump head will help)

water should dribble out in a steady very slow trickle, also spin pump impellor to make sure its not stuck

replace screw check system press is 1 bar ish and run ch

if pressure rises to 3 bar exp vessel dead/needs recharged

 

[mug51]

thanks for the reply glasgowgas, havent vented the pump, but just looked up venting pump in the faq bit and it says to loosen auto air vent. i done that earlier, would that mean i havent the pump?

at the moment im draining the ch system, as in faq. what would be the best way to fill the system to make sure no air is in there? all i know how to fill it up is using the grey filling knob. would i keep a radiator bleed valve open when filling?

got a call from BG guy and says its gonna be £150, but wont be today, he thinks its air in the system

 

[glasgowgas]

im gonna get a coffee, back in 5 mins, this could take a while

 

[kevplumb]

View media item 17592
and spin the pump while you have the screw out

 

[glasgowgas]

right first thing first. close all drain cocks

remove front cover from combi

make sure all rad air vents are closed

fill combi to 1.5 bar showing on gauge

start from downstairs start venting rads of air. as soon as water comes out in a steady flow close rad air vent

go back to combi, check pressure, top up to 1.5 bar

go to next downstairs rad and repeat

after all rads are vented and pressure is at 1.5 bar, close auto air vent and open it back up 1/4 to 1/2 of a turn. the auto air vent now stays in this position forever and ever

now to vent the pump, you need a decent flat bladed screwdriver, fairly thin flat screwdriver and a tea towel

place tea towel underneath pumphead, remove centre silver screw with large flat bladed driver, water will come out, not like opening a tap, just a steady dribble. using thin flat driver rotate impellor to make sure its not jammed or stuck

replace central screw in pumphead

check pressure and top up to 1.5 bar if reqd

combi,pipework and rads are now all free of air

turn on central htg and check and monitor temp and pressure

you will get some hissing from auto air vent, thats ok its meant to do this

post back when you have done all this, its pretty straightforward, if you think you have missed something, start from the start and work progressively through

small edit, you have a sealed system, remember any time you take from the system (ie venting rads at a later date) you have to put back into the system (ie filling through filling loop)

 

[mug51]

right first thing first. close all drain cocks

remove front cover from combi

make sure all rad air vents are closed

fill combi to 1.5 bar showing on gauge

start from downstairs start venting rads of air. as soon as water comes out in a steady flow close rad air vent

go back to combi, check pressure, top up to 1.5 bar

go to next downstairs rad and repeat

after all rads are vented and pressure is at 1.5 bar, close auto air vent and open it back up 1/4 to 1/2 of a turn. the auto air vent now stays in this position forever and ever

now to vent the pump, you need a decent flat bladed screwdriver, fairly thin flat screwdriver and a tea towel

place tea towel underneath pumphead, remove centre silver screw with large flat bladed driver, water will come out, not like opening a tap, just a steady dribble. using thin flat driver rotate impellor to make sure its not jammed or stuck

replace central screw in pumphead

check pressure and top up to 1.5 bar if reqd

combi,pipework and rads are now all free of air

turn on central htg and check and monitor temp and pressure

you will get some hissing from auto air vent, thats ok its meant to do this

post back when you have done all this, its pretty straightforward, if you think you have missed something, start from the start and work progressively through

small edit, you have a sealed system, remember any time you take from the system (ie venting rads at a later date) you have to put back into the system (ie filling through filling loop)

you are a genius, it worked
thank you ever so much

 

[mug51]

oh i got one more question, since i drained my central heating system, i imagine i need some sort of water treatment put in.

do i put in inhibitor, central heating protector or both?

thanks

 

[glasgowgas]

pop in 1 litre of Sentinel X100 and you will be ok

 

[mug51]

pop in 1 litre of Sentinel X100 and you will be ok

great

thanks again