Boiler pressure question

longwalks1

We had a new Worcester Bosch combi boiler fitted 3 months ago, it replaced the old open system with 2 tanks in the loft. Water pressure in all our taps improved massively as we expected. One thing I’ve noticed is with the shower on full, and running the downstairs toilet tap on full, the boiler loses pressure (on the gauge on the front of the boiler) after a few minutes. Is this normal?

I was under the impression that any loss in pressure is a leak, but I can’t find one?

If running the shower and taps on full was taking too much water from the boiler, could the drop in pressure be because the boilers not filling quick enough?

Ruski

Pressure gauges on Combi's are system pressure, not 'hot water pressure' - so if you run hot water and the pressure drops - and stays dropped - then you have a problem. It's under warranty, get 'a man' in Demonstrate what is happening and let them worry about it.

HTH

Russ

n.b. unless Worcester Bosch have a new boiler which has a 'hot water pressure' gauge... then ignore this post!!!!!

Ectophile

The pressure gauge on the front tells you the pressure in the central heating system, not the hot water. There should be no connection between them - the central heating system is full of corrosion inhibitors, and you don't want those in your hot water.


Combi boilers can't do central heating and hot water at the same time. When you turn on a hot tap, it turns off the heating. If you use hot water for long enough, the heating could cool down and the pressure drop a bit.


The pressure gauge will go up a bit when the heating is on, and back down again when it goes off. It drops below the "normal" mark on the gauge when cold, then you've lost pressure. If it's a new system, that could possibly just be trapped air escaping. I would only worry if it keeps doing it.



Otherwise, there's something odd going on. It definitely shouldn't go down and stay down when running the taps.

longwalks1

Thanks guys, totally makes sense now (trying to educate myself a little)


Ectophile - have played around with it some more and we did have the shower and hot tap running on full for 10 or more minutes, and the pressure does rise again once we switched off.


Thanks both