New boiler not working as pressure 0 bar! Help *PigletJohn* [blush]

[dabchick88]

We had our new combi installed on Friday and all was well until we went to admire it on Saturday and noticed the screen was flashing 0.5bar pressure. The heating was still working.
By today the boiler had shut down and was displaying 0 bar pressure. We currently don't have any taps in use as we are renovating (the house is a shell) so haven't been using water just heating.
I called the company that fitted the boiler and they said it was probably just air in the system and to fill it up to raise the pressure.
Is air likely to be the problem, I don't really understand why there should be air in he system, surely they should install a boiler so its going to work not shut down within 48hrs because of some air?
I will ring them again tomorrow as they said they would come and check it, I just wanted another opinion as I'm aware i don't really know much about boilers and what is normal or not and don't want to seem like an idiot if I'm making a fuss about nothing. I read somewhere that the most likely cause for a pressure drop is a leak. I cannot see any leaking water and again, surely this shouldn't happen so soon? any help appreciated

You need to use the filling loop to get the pressure up to the recommended amount - about 1.5? See how you go but you shouldn't need to keep doing it.

Doesn't sound too weird for a new boiler - if it kept happening I would be worried, but as a one off I would just fill it and see how it goes.

The filling loop is probably under the boiler, and will have two little taps which need turning on. The first time mine did it, the plumber explained what I needed to do, and I sensibly wrote it down in the back of the manual with a little drawing.

I was very glad I had done this, when it happened again about 18 months later (because I'd inadvertently left a tap in the bathroom slightly on all day.) I had no memory of what to do without the little drawing. So once you've found out which little taps need turning, make a note of it for next time.

It has nothing to do with leaving taps on.

If it is due to air, it may help to bleed the radiators.

Do not over-pressurise it.

Look at the pressure relief valve that (probably) comes out of the wall, outside, behind the boiler and is curved back so that any water squirts back against the wall, and not onto passers by. It should never drip.

The other cause of pressure loss is leaks, so look at visible pipes and especially underneath radiators.

Surely leaving a tap on will have a similar effect to a leak? (If it's for long enough.)

Nope.

Our pressure went on our newish boiler recently. If you look in the manual that came with it should show you how to refill the loop to regain the pressure.

Ours was caused by a tiny leak in a radiator in the bathroom which had become worse (never more than a small dribble which we hadn't noticed). So you probably need to bleed the radiators to remove any air. But also check for any minor leaks just in case.

You should be able to hear if there is air in the system if you'd had it switched on before it shut down because the pipes and radiators make knocking sounds as they fill up.

Ours has a key thingy which is stored in the underside of the boiler and needs be put into the bit under the loop part (sorry for lack of technical explanation but our manual explained it much better than this!).

Thanks everyone for help. The boiler was refilled on Monday to the correct pressure and the radiators were checked, but apparently didn't need fully bleeding. There were no signs of leaks from any of the radiators according to the engineer and he said the radiators still had water in them and he would have expected them to be nearly empty if there was a leak.
HOWEVER today at lunchtime the pressure had dropped again to below 1bar. I have now refilled it to the acceptable pressure but am worried that we shouldn't have to keep filling it up, its has now been twice in four days. Maybe this is normal for a new system and it could just be air in it? The only thing being used is heating (not water atm) and this is on for 2hrs am and 2hrs pm.
Should I be worried or just keep topping it up and hope for the best for now?

if there is a leak, the water comes out as long as there is pressure, then it stops. The radiators would not be empty unless you had at least TWO large holes.

the plumber is either pulling your leg or is an ignorant buffoon.

You have a leak.

Did you look at the pressure relief pipe?

I was told by my plumber that there doesn't have to be a big leak for the pressure to drop on the system. Ours was never more than a tiny dribble. It may be leaking from a pipe you can't see - under a floorboard rather than from the radiator.

The fact that you mention the flashing 0.5 makes me think you may have a vaillant ecotec boiler? They are prone to leaking from the diverter valve and rubber hoses within the boiler itself.

Although re-reading the op it's a new boiler so less likely. It will be a leak as PJ says. It has to be.

Our leak is a seep from a radiator valve and it lowers our pressure within a week. Barely damp but it doesn't need to be much, it's only emptying the tiny bit of water in the boiler.

Indeed we do have a vaillant ecotec Spanglecrab I'm impressed
We have now found a leak, what a relief. Hopefully it will get fixed tomorrow. The boiler is new but some of the pipework is quite old so lets just hope we don't get anymore leks springing up!

Also to put your mind at ease the newer ecotecs have done away with the dodgy rubber hoses and have re-designed the leaky diverter valve.

So we have been quoted about £100 to fix up this leak as it was coming from our old pipe work (not any new pipework they had laid) so wasn't included in what we had already paid.
The pipework is old and now there is a high pressure in the system leaks are apparently pretty normal.
They also suggested that because this might happen again and as we are doing the house up, laying new flooring etc that we might consider replacing all of the pipe work on the ground floor. This would prevent us having to rip up nice new flooring if the old pipes cant take the pressure. The suggested this would cost about £1000. Does anyone have an opinion on whether we should do this? All help very much appreciated

If you lay laminate or hardwood flooring, it will a sad day when if it comes up afterwards (and expensive).

Soldered joints on copper pipes seldom leak even if old, but if course you won't know until you look.

I presume they can lift the carpets and use the same cuts in the floorboards as were used when the old pipes were put in.

You don't need to pay gas engineer rates to lay pipes, it is a plumbing job. Ask what rate they have used, and if they think it will take more than two days. A small firm may not have a plumber.

When the pressure goes down on my boiler ( particularly after bleeding radiators) I have 2 small black taps at the front of my boiler underneath which I turn on till the pressure goes up to 1.5 - 2 on the dial and then I turn them back off. The boiler starts working properly and all is well again.

There are 2 small black taps at the back of my boiler underneath and these are not the ones to turn. I found it quite hard initially to locate the 2 small taps I needed at the front underneath but they were there. I have a back boiler if that helps.

Thank you PigletInABlanketJohn. Yes we were thinking laminate or engineered wood and that was my thinking exactly!
They said it was a couple of days work no more and that their standard going rate is £45 an hour I think.
The leak was from a pipe where the soldering was not good, so maybe this was just a one off on one of the joints. I have asked them to assess the situation when they repair the current leak this afternoon and then let me know what they recommend based on the quality of the rest of the pipes they can see. At the moment its very easy to gain access to the pipes as we can just lift the boards and the carpet is being binned. Obviously financially its in their interest to get more work/money but they seems snowed under at the moment so we'll see....

We had leaks after installing a new boiler. four in total. fixed the first three, temporary fix on the fourth while the plumber organised to come back and replace all the pipes under the wooden floorboards. unbudgeted for expense but so far no further problem. BTW everytime we fixed a leak, it would be okay for a week or two, then start to drop pressure a bit, then drop pressure quicker as the leak accelerated until all pressure dropped. always easier to find the leak then as it was usually gushing out. leaks were always at joints of old pipes. the higher water pressure seemed to test each weak joint in turn until it went, and then move to the next weak joint when we fixed the problem

Were they soldered joints that failed, or compression?

It's good that you've found the leak and can get it fixed. I might consider having the work done just because it's easier now - but depends on budgets of course. Gutting to spend time and money doing it up and then have a leak.

soldered joints. old system, copper pipes etc. changed from a vented system to a combi boiler and understand that slightly higher pressure from combi boiler. previous boiler was over 30 years old and never had a problem but changed as had separate boiler and water heater, both quite old and it seemed to make sense to have one more efficient boiler. a stressful couple of months to be honest! and cold

We are in the same situ as wufti I believe. Old back boiler. Old pipes with soldered joints. So frustrating as getting the engineers back is proving to be a bit of a nightmare, they haven't bothered to show up twice now! Just want some heating!