central heating

[dmacca3]

hi can anybody help i have a woscester bosch combi boiler and the water pressure keeps dropping, it usually takes a few days before the radiators wont heat up. i have recently redocorated and removed the radiators , refitted and bled them and i cant find any leaks anywhere.
thanks dave

 

[adlplumbing]

if you can not find leak on the rads by using tissue paper then check the blow off pipe(prv) on outside see if it is dripping

 

[AkuraEngineer]

if you can not find leak on the rads by using tissue paper then check the blow off pipe(prv) on outside see if it is dripping

lol a blow off pipe! never heard it called that before haha

either you have a leak somewhere maybe rads pipework under the floor
your pressure releif valve is letting by or prv (blow off haha cor)
or your expansion vessel is flat and it needs pumping
or alternativly youve topped up the pressure to 1 bar bled a rad and maybe are a bit confused as to why the pressure has gone down so quick?

 

[dmacca3]

what should the pressure gauge be set to on a woscester bosch combi boiler
thanks

 

[kevplumb]

lol a blow off pipe! never heard it called that before haha

ain't been around pressurised heating much then


pressure should be 1 to 1.5 cold

 

[AkuraEngineer]

on most standard sealed systems or combi boilers you want to get the pressure between 1 and 1.5 bar as kev the plumber said do not make the mistake of topping it upto 2.5 or 3 bar as you have to allow room for expansion to take place which means if youve topped the pressure upto 1 bar when the heating is fully up to temperature the pressure will increase to maybe 1.5 bar this is normal, normal operation, accept it, its the law, laws of physics

having said that if you top the pressure up to 1 bar and it shoots over to 3bar almost immediately you proberly have a problem with your expansion vessel ill shut up now sorry