Is low pressure dangerous?

[carlosuk]

Hi,

I live in a rented house which has an Ideal Classic FF230 Sealed System boiler, and had to have British Gas come out a few days ago as the pressure kept going too high and thus opening up the pressure release valve, which was as I suspected down to there not being enough pressure in the expansion vessel, which the engineer rectified.

Once the system heated up again, he went to see if there was water dripping out of the PRV, which to be fair their wasn't so he left.

The next evening, I noticed the cold pressure had dropped down to just above 0.5 bar, which was quite a drop as the engineer had topped it up to 1.5 bar the day before, so I topped it back up again and went to check the outlet from the PRV, which again didn't appear to be dripping and all seemed fine.

I have noticed today that the pressure when cold dropped to almost 0 bar, and when checking the outlet from the PRV, there is a stream of ice running from it suggesting that water is being released from there, so I have notified the landlord to get British Gas back out, and have topped up back to 1 bar.

What worries me is that the pressure seems to be dropping quite quickly, and am concerned as to will it damage the boiler if it fires up with such low pressure, as I don't want it to pack up with the weather being what it is, and as BG will be coming out at some point, should I not be worried in the mean time?

Many thanks,
Carl.

 

[twgas]

keep an eye on the pressure so it doesnt get too low - easier said than done, but it is fairly important.
There should be an overheat 'stat on the boiler if it's on a sealed system so there shouldn't be a major problem but if you turn the boiler stat down to about 2 it will help prevent probs.

 

[ChrisR]

See Boiler Pressure Problems in the faqs. The man should have let the pressure off the system and chacked the expansion vessel precharge pressure.

 

[carlosuk]

See Boiler Pressure Problems in the faqs. The man should have let the pressure off the system and chacked the expansion vessel precharge pressure.

Hi ChrisR,

This is what he did, he released all the pressure using the PRV and then checked the pressure in the expansion vessel which he found to be too low and then pumped it up again and recharged the system to 1.5 bar.

Thanks.

 

[carlosuk]

keep an eye on the pressure so it doesnt get too low - easier said than done, but it is fairly important.
There should be an overheat 'stat on the boiler if it's on a sealed system so there shouldn't be a major problem but if you turn the boiler stat down to about 2 it will help prevent probs.

Hi Mick,

The boiler does have an overheat stat, so can I summise that if the pressure drops too low overnight, worst case scenario this will activate stopping the boiler from firing up (and cause a freezing cold house!)?

Carl.