Pressure rising hot water on

[alan alkeson]

Hi my Main Combi pressure goes into red when using hot water. I was told today that expansion vessel may be blocked as i had a new boiler fitted onto old rads. I just hoped id get some idea if that could be the fault.

 

[terryplumb]

What does pressure rise to when central heating is running ?

 

[alan alkeson]

It doesnt it stays under 2 just rises from 1.5 but thats just normal expansion isnt it?.
thanks for replying cheers Terry

 

[terryplumb]

Go around all your radiators and bleed them of air. If lots of air comes out top up pressure to 1 bar . Then see what effect this has on pressure . Your EV is suspect.

 

[alan alkeson]

Thanks Terry no air out of rads so you thinking expansion ?. I was pricedjust 5 min ago on powerflush and clean EV £480. I said "ok but guarantee it will be fixed" "we cant guarantee that" so basically its £480 to flush the system and maybe im wrong but flush clean vessel ? it wont will it ?.I have got to get it fixed but not pay for jobs that arent going too sort it.

 

[alan alkeson]

I am going to undo the ev pipe connector and see if its blocked

 

[terryplumb]

I am going to undo the ev pipe connector and see if its blocked

Are you sure you know what your doing Alan ? Who advised you on the powerflush ?

 

[terryplumb]

Do you have a magnetic filter on the system ?

 

[ianmcd]

your expansion vessel only comes into the equation when the heating is operating, running HW only will not effect the expansion of the system water, if everything is working properly, power flush most definately not the answer