New Grant boiler losing pressure but still working?

[braduk80]

Hi everyone,

We've recently had a new Grant oil condensing boiler (26K) fitted by a reputable local firm which, other than a faulty flow switch which was changed after a couple of days has been working well.

Recently, after 2 or 3 weeks of its installation the boiler has been firing up at around 3 or 4am for about 10 minutes and making a massive noise (gurgling, water sounds etc). The pressure guage was at zero despite the low pressure light not being on and the central heating & hot water still working.

I bled the radiators (lots of air in the upstairs, fine downstairs) and repressurised to 1 bar. Within a few hours it was back to zero. I repeated the exercise and again, it dropped to zero.

Speaking to the company they felt it could only really be a leak in our closed system which is causing the loss of pressure. He did say that the boiler might be dumping out of the little white pipe and to put a balloon over it to check whether it fills up. I've not done this as yet (primarily as I've not been around in daylight hours and the pipe is high up as the boiler is located upstairs in the eaves of our main bedroom).

Sorry for the long winded explanation - my questions are:

- Is it likely we've got a leak? Most of our pipes are cemented in and so would be very difficult to find. Our previous boiler never lost pressure. If we do have a leak could the "power flush" they conducted on install be the cause of this?
- Is it significant that despite the pressure being displayed as zero that the low pressure light hasn't come on? In addition is it not odd that both the central heating and hot water appears to be working perfectly?
- What could be the reason for the loud gurgling noises the boiler is making when firing and is this possibly related to the other symptoms?

Again - sorry for such a long post! The plumbers / central heating company that installed it didn't seem keen to visit us to check it out and before digging my heals in to ask them to come back I wanted to know whether we feel it is something they should be investigating.

Thanks in advance for any help, advice or direction you guys might be able to give me.

Cheers,
Brad

 

[lufcmark]

My advice would be to get your installer back...The more you tamper with it yourself the more you leave yourself open to blame or warranty issues.

 

[lufcmark]

By the way I am assuming that your installer supplied the boiler.

 

[slapper]

If I fit a sealed system,I give the customer notice that any leaks incurred thru a pressurised system,is not the responsility of the installer.

No body can guarantee that leaks wont happen, the installer should have highlighted this before commencement of work.

Cheapest option if there is a leak is using a leak sealing agent into system,as a temp or permanent cure. Good Luck

 

[braduk80]

Thanks for the replies guys.

Got back home tonight, checked the boiler - pressure zero & low pressure light on this time.

Repressurised again to get some hot water for tonight and as soon as I turned the boiler back on, it started to drop from 1 bar slowly down.

Went outside to check the pipe to see if it was emptying but nothing obvious. The main vent pipe was arcing out steam though (is this usual?)

Went back inside and pressure was up to 1.5 bar (first time this has happened) so decided to turn it off. As soon as I did, the pressure gauge jumped to 2 bar after the power was off. Presumably this could be a faulty pressure guage?

I don't *think* we've got a leak; at least not one of the order that causes the boiler to rapidly drop from 1 bar pressure to zero.

I'll give the installers another call tomorrow; but in the meantime does anyone recognise the symptoms? Is it likely to be a fault with the boiler or do all signs point to a leak somewhere?

Thanks for all your help

 

[Tibbot]

Seems you're describing a combi. Yes/no which model is it eg Vortex pro 26 combi, system or regular with external sealed system components?

 

[braduk80]

Yes indeed - Grant Vortex Combi 26e. Sealed system although not sure against your question there.

 

[Tibbot]

Has the installer fitted another external expansion vessel or just relied on the one in the boiler (red round vessel in behind case)? If so expansion capacity is inadequate unless you have only a couple of rads.

The existing vessel may have lost its air pressure and need recharging. Make sure you vent air when refilling with water there are 1 or 2 manual air vents (depending on version).

Grant had problems with leaking primary pressure switches and HW flow switches (machined too deep and sticking) both cured.

By steam from main vent I presume you mean from flue. This is condense pluming and is normal.

 

[braduk80]

Interesting - thanks so much for that. The company were adamant that it could really only be a leak in our pipes - I'll call them back again tomorrow and ask them to come out to check into it. Sounds like you've come across this issue before.

It's annoying as they convinced us to install a new boiler (our old Potterton Flowsure statesman kept overheating within minutes but the overheat didn't kick in so the temprature kept rising!) at a cost of around £2,850 and then as soon as we've paid were happy to leave us high and dry.

Really appreciate the feedback

 

[Tibbot]

(our old Potterton Flowsure statesman kept overheating within minutes but the overheat didn't kick in so the temprature kept rising!)

Too late to ask then if anyone tested or checked the thermostat phials were actually inserted in their pockets

 

[braduk80]

Couldn't be sure if they were tested although apparently the thermostats were changed (plumber 1 did this). This didn't solve that particular problem and the second plumber believed it was due to a scaled up heat exchanger although advised that the boiler was also underpowered for our house. He also said that parts were difficult to get as Potterton no longer made that particular type of boiler (he was generally disparaging about Potterton's oil boilers). In the end we got a 3rd plumber out as the second suggested we consider a new boiler and the 3rd plumber came to the same opinion.

Unfortunately, not having the first clue about boilers I had to assume that these firms were being honest with me and not just trying to flog me a new boiler!

As I understand we didn't have another external expansion vessel fitted - is this a given for this particular model for a house of around 15 radiators? The boiler is still under warranty so I presume I could ask Grant to check the primary pressure switch for a fault too?

Again - thanks for your help. Very good of you!

 

[leakydave]

Grant Boilers are my number 1 choice as far as oil goes. Not had too many problems with ones I've installed.

 

[Tibbot]

As I understand we didn't have another external expansion vessel fitted - is this a given for this particular model for a house of around 15 radiators? The boiler is still under warranty so I presume I could ask Grant to check the primary pressure switch for a fault too?

As you have the 'e' model don't worry about switches as they seem to work, most probably new type anyway.

Expansion vessel is a must. The built in boiler one is the biggest that Grant can fit in the case and they clearly instruct you need another on the system. The size of this is calculated by the installer.