Intermittent problem with Grant Vortex boiler

[SPD]

Having similar problems with a 3 year-old Grant Vortex 15-26S. First of all the filling valve seized and had to be replaced. Then the expansion vessel started to leak and needed replacing. Over the past week the pressure has varied between 0.25 and 1.5, needing topping up every couple of days. I have no confidence in this brand - wish I'd stuck with Worcester! Plumber will be out again tomorrow to see if he can sort it out. I can't understand why Which gave Grant a 'Best Buy' rating .........

Grateful for any suggestions as to what the problem might be, given the expansion vessel has been replaced and the pressure checked.

Susan

 

[Boilerman2]

To be fair a lot of the complaints listed are likely to be "system faults" and nothing to do with the Grant Boiler!! lets keep it in perspective!! The Grant is one of the best oil fired boilers available, but only if installed into one of the "best Systems" !!

 

[SPD]

Boilerman, I don't think the problems my boiler is showing have anything to do with a poor system - it's all new, installed by a qualified engineer and plumber. No leaks on the rads or underfloor system (he's already checked that).

I'm also less than impressed with Grant's customer service. I contacted the Tech Dept and was promised a call back. Nothing. Emailed via their 'Contact Us' section, nothing. That's why I'm asking for advice from this forum.

 

[dcawkwell]

Installed my first grant a few months ago.
Not by choice customer has already bought it.
Can't say I was impressed. I usually install warmflow.

Didn't like the flue connection method.

Can't vouch for their combi boilers.

 

[boilergonbust]

Our Grant vortex is now 6 years old and once again we are going through this problem. After pressure vessel and make up loop was changed the pressure stayed constant for a couple of weeks but it is now cycling from 1 bar down to zero in 2 weeks. No sign of a leak in the system. I am getting our heating Tech. to check it out.
We had lots of problems in the first 2 to 3 years eventualy Grants technical director visited changed a lot of components and it ran OK until this summer.
Would not use Grants again, Have installed a Worcester in our other property with a 5 year warranty.

 

[Norcon]

If your fitting combi's then thats where you're going wrong.
They're the biggest heaps of over priced junk ever invented no matter what model. Everything crammed into a tiny box.
Wouldn't take the gift of one. Their main attribute is keeping boiler technicians in work.
My heat only Grant boiler is running non stop now for 14 years and never serviced. Only changed a £10 capacitor in that time.
I keep a spare burner just in case. Any problems , 10 minute job to change it over. Then the old one benched.
Murphy's law runs in reverse with that approach I find.
Best boiler ever.

 

[oilhead]

Went to a Grant Vortex combi last week, not quite 2 years old with a perforated plate heat exchanger. !st class service from Grant with the part, but after draining down to change it, 2 of the 3 AAV's would not seal.
I would suggest looking at these as they are a pain on any boiler. This why Worcester have manual vents.

 

[audiofred]

My daughter bought a house in Somerset last year (2012) and had problems with the boiler losing pressure and needing frequent topping up.

The boiler is a Grant Outdoor Vortex Combi about three years old.

The previous owner had clearly had the problem and we have the plumbers bills to prove it! The pressure vessel, PRV (pressure relief valve), low pressure switch and even the filling loop had all been replaced by their plumber.

It was clear to me that the pressure was rising too high and being released by the PRV, (I put a container under the discharge pipe to prove it). Then, when the water cooled, the pressure dropped too low to enable the boiler to start up again. The PRV on this boiler is set to 2.5 bar.

I decided to put an additional pressure vessel in the system, putting it under the kitchen sink and connected to the return pipe to the boiler. I also fitted a pressure gauge and filling loop with it, so if the problem persisted, I wouldn't have to go outside to recharge it! I reasoned that it would be best to fit a larger vessel than is theoretically needed, so I fitted an 18 litre vessel (setting the air pressure to 1 bar). This was then in addition to the 10 litre vessel in the boiler.

This has completely cured the problem. The pressure now never rises above 1 bar, even when the heating is working all day. Since the initial charge it has not needed topping up at all.

p.s I am not a professional plumber, just a reasonably competent DIYer. You can buy the parts required fro Screwfix or Tool Station etc., but I got the vessel, gauge, filling loop and a PRV as a kit on eBay for about £50. (The PRV was not needed as this already exists in the boiler).

 

[Agile]

Fred, all very well fitting an external EXV.

But before doing that what had you done to check and repressurise the internal one?

Tony

 

[oilhead]

External vessels solve most of the problems with oil combis and system boilers. Internal vessels are often undersized, Grant only put a maximum 12 litres into a 140,000 Bthu boiler.

 

[audiofred]

Hi Tony,
You asked what I had done to check and re-pressurize the existing vessel. This was a new one fitted in June 2012 by the previous owner's plumber. I checked that there was no water in the air side and that the pressure was 1 bar when the water pressure was zero. (1 bar is what Grant specifies).

I had previously checked for signs of leaks of course and I put some Screwfix No-Nonsense leak sealer in the system in case there was a leak where I could not see it.

By the way, because I could not be sure how much inhibitor was left in the system, I put some more in to make sure.

 

[SPD]

The boiler's still playing up. Plumber came around just before Christmas, checked pressure again in expansion vessel (OK) and checked for leaks on the system (none). It ran OK for about a week at 1 bar cold to 1.5 working, then when I checked this morning, before it fired up, it had dropped to 0.3 cold, from having been set on 1 bar cold a week ago. The puzzling thing is, after it's fired up and without repressurising, it reaches 1.5.

I had put a plastic bag over the PRV outlet, but there's no water in it.

I spoke to one of the Grant's engineers this morning, and he was puzzled as to what the cause could be, with the obvious culprits being eliminated. I checked the 2 AAVs as I was talking to him, and they weren't stuck.

The only other thing I noticed was that during the Christmas period the weather was quite cold so the boiler was running more frequently and the pressure stayed pretty constant. The last 2 nights have been quite mild, so it hasn't come on during the night; it's stayed off until the thermostat calls for a rise in heating at 0630. The 'off' period seems to have coincided with the pressure drops.

Grateful for any ideas ........

 

[SPD]

The story of woe continues. Boiler has been running pretty regularly during cold spell, with only brief periods when it wasn't required for the heating, and the pressure has ranged between 0.4 and 1.2. Last night was a mild one, so the boiler wasn't called for about 8 hours (house temp stayed above nighttime 18degrees). Checked this morning at 0615 - pressure had dropped to 0.1. Checked the bag I'd put on the outside PRV outlet - nothing.

The Grant Tech Dept man doesn't know what it is. I've called out the plumber/installer 3 times for the same problem without a solution. Can anyone out there help please?

 

[snb]

External vessels solve most of the problems with oil combis and system boilers. Internal vessels are often undersized, Grant only put a maximum 12 litres into a 140,000 Bthu boiler.

This is often the case. the smaller ones have the 12lt vessel and the larger have the 14lt vessel.

Most cases of pressure loss are caused because of installers not calculating the required vessel size.

This is because on gas boilers and with system oil boilers the vessels have enough size for at least 8 to 12 rads.

On oil combi boilers they have 40 to 70 lt stores attached but do not fit larger vessels. this often means more than about 6 to 8 rads and you will have problems.

grants are normally reliable. EXCEPT for their external combis which often have the store pcb fail due to corrosion.