Combi has boiler - losing pressure.

[BerryMummypudding]

We had a combi gas boiler fitted in October.
It's a Ideal vogue combi 40

If I put my washing machine and dishwasher on at same time the boiler looses pressure

Is this normal?

If you are in UK then the washing machine and dishwasher will almost certainly take from the cold feed only so there is no connection between the two

My first question would be why are the machines connected to the hot water ?

Washing machine is usually cold fill.Dishwashers can be both, but newer ones also cold fill. So should not be affecting your boiler.

Best call a plumber qualified to look at gas boilers and also have him check the connections to your machines.

Not normal.
A new boiler probably needs a pressure update after a couple of months, then again in 2-4 years.

Get someone out to check it, sounds like some sort of leak.

Oh! So what would be a reason that the boiler looses pressure. It was put in in October, I had to fix pressure in boiler in December and again today. Surely that's not right?

Or maybe it is.

It's bloody annoying as boiler is in loft.

Good point @Dearg can't remember last time a dishwasher or washing machine had a hot water feed.

Does the pressure go up again ?

No, it's not normal for it to lose pressure. You either have a slow leak somewhere or the boiler is faulty.

A boiler circulates the water for the radiators in a sealed pressurised system.
Your hot and cold water supplies that you bathe and wash in, and run appliances from is separate to the heating system.

When the washing machine is on, cold water is drawn, but this is a separate system. So the loss of pressure to the boiler must be from something else than your washing machine.

Reasons for losing pressure can include:

Auto air vents purging air from a new installation
Leaking valves / jonts on radiators or pipe unions
Cracked heat exchanger - water from leak will drain down combi drain to waste
Pressure relief valve not sealing - you should see staining etc from PRV drain
Pressurisation tank internal split on diaphragm
Pin holes in pipes or fittings

Are you saying you go up into the loft to look at the boiler when you use the washing machine and/or dishwasher?

Anyhow ... if you've only had it a couple of months get the installers back to look at it.

I've got the guy who installed my boiler 15 years ago coming to look at the thermostat on Friday!

@Tumbler2121 no. We realise there is something wrong when we have no hot water or radiators don't heat. At that point I go up there and can see the low pressure warning on the digital screen.

I was just checking this isn't a normal thing before I call the installer back.

Sounds like there is a leak somewhere. I would definitely get them back.

We had this, there was a leak, get them back ASAP.