WORCESTER HEATSLAVE 15/19 PRESSURE RISING

[NACD]

I have a worcester heatslave 15/19 oil boiler which has a rising pressure problem.The pressure gauge rises slowly when in use and then drops when not in use.I have disconnected the filling loop and checked the expansion tank which seems to be fine ie correct pressure and no water showing .The pressure also drops when the hot water tap is running which leads me to believe that the heat exchanger is the problem .I would appreciate it if anyone could adsvise me as to what the problem might be.Thanks in advance for any help offered.

 

[MrGassafe]

Unless you have to top up the pressure with the filling loop then there is no problem.

It is normal for pressure to rise when boiler is hot and drop back when
cold.

 

[NACD]

Unless you have to top up the pressure with the filling loop then there is no problem.

It is normal for pressure to rise when boiler is hot and drop back when
cold.

Thanks MrGassafe for your reply,I know that the pressure rises when the boiler is working but it,s the amount it rises that worries me.It keeps going up until it blows off through the pressure relief valve which leads me to believe that it is getting mains pressure somehow which is why I think it might be the plate heat exchanger .I also think that there may be a problem because when the boiler is running, turning on the hot water tap allows the pressure to drop.Any advice would be gratefully recieved.

 

[Agile]

If cold into the boiler is turned off and running on CH then a cold pressure of 1.5 Bar should go to to about 1.8 Bar.

Merely having air pressure in the EXV means nothing! It needs to be emptied and repressurised in accordance with the FAQ.

Turning on hot water taps should have no effect on pressure in the boiler and if it does this with the filling loop removed indicates the secondary heat exchanger is leaking.

Tony

 

[NACD]

If cold into the boiler is turned off and running on CH then a cold pressure of 1.5 Bar should go to to about 1.8 Bar.

Merely having air pressure in the EXV means nothing! It needs to be emptied and repressurised in accordance with the FAQ.

Turning on hot water taps should have no effect on pressure in the boiler and if it does this with the filling loop removed indicates the secondary heat exchanger is leaking.

Tony

Thanks Tony for your reply the filling loop is disconnected but the pressure is still creeping up and it does drop when the hot water tap is run I think you may be right that the secondary heat exchanger is the problem .Can these be fixed or will it have to be replaced?.