Any boiler experts?

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Our Vailant boiler has one heat exchanger which services both hot water and central heating. There is a motorised diverting valve that directs the flow to either or both loops/circuits. So for our system if the central heating works and the hot water doesn't, it ain't the boiler.

Which model boiler do you have?
 
The expansion vessel is pressurised circular flat vessel divided across its width by a rubber seal and is pressurised on one side. It's purpose is to balance the pressure evenly in the system and take up expansion as the Htng water temp rises, and expands. Some have a shrader valve on top where pressure may be checked, if it has lost pressure due to failure of the diaphragm when the Htng comes on, the water heats and expands the pressure gauge will rise into red zone and to save explosion, pressure relief valve will open and complete loss of pressure and system fill will occur. This then is unlikely in your case as you still have Htng. When system is cold some should be filled to 0.5 bar most up to 1.0 bar, when Htng on gauge will read 2.0 to 2.5bar at most. At 3.0 bar danger and pressure relief opens. The heat exchanger is unlikely to be scaled up unless the boiler is getting old. You live in a hard water area. There is no scale master, or softener fitted in the mains water fill, and possibly sludged, if there is not a magnatec sludge connection originally installed in the system. Your best bet is to get someone round to look at it who knows what he's talking about, a Vailant engineer. Would be best, yes it will cost a few bob, but it's really the only answer, it's a bit like your MB combis , are complex and different manufacturers have differing designs depending on types of system requirement. Good luck it may just be something simple.
 
The expansion vessel is pressurised circular flat vessel divided across its width by a rubber seal and is pressurised on one side. It's purpose is to balance the pressure evenly in the system and take up expansion as the Htng water temp rises, and expands. Some have a shrader valve on top where pressure may be checked, if it has lost pressure due to failure of the diaphragm when the Htng comes on, the water heats and expands the pressure gauge will rise into red zone and to save explosion, pressure relief valve will open and complete loss of pressure and system fill will occur. This then is unlikely in your case as you still have Htng. When system is cold some should be filled to 0.5 bar most up to 1.0 bar, when Htng on gauge will read 2.0 to 2.5bar at most. At 3.0 bar danger and pressure relief opens. The heat exchanger is unlikely to be scaled up unless the boiler is getting old. You live in a hard water area. There is no scale master, or softener fitted in the mains water fill, and possibly sludged, if there is not a magnatec sludge connection originally installed in the system. Your best bet is to get someone round to look at it who knows what he's talking about, a Vailant engineer. Would be best, yes it will cost a few bob, but it's really the only answer, it's a bit like your MB combis , are complex and different manufacturers have differing designs depending on types of system requirement. Good luck it may just be something simple.

Vailant fixed price £249 repair may be what I go with
 
Is it the main heat exchanger that was wrong with yours?

Vokera, only has a single heat exchanger in it.
Had a problem after that of being clogged up with gunk that caused the pressure relief valve to go as the water couldn't circulate properly. Cleaning the muck away sorted this.

Have a Vaillant at work that I think since 2001 has had every part replaced at least twice!
 
Booked with Vailant, £49.98 per month for 6 months. Including all parts even main heat exchanger etc.

6 months of cover by Legal & General

Doesn’t cover sludge/scale but then the plan will be fully refunded so no cost

Being sorted on Friday

Very happy
 
Hi, do you remember what parts were replaced? Was it the ‘heat exchanger’ as this isn’t included in the fixed price repair

Thanks
Pretty sure it was the heat exchanger. The unit had got blocked so restricting the flow. Most noticeable when running a bath as only slow flow was hot. Open the tap fully and the water went Luke warm. Had it replaced and th magnetic filter installed and all fine now. Think the big improvement has been that I can add inhibitor via the filter so no more corrosion in the pipes. Filter comes out clean now when I check. All has been fine for a few years now so fingers crossed!
 
Booked with Vailant, £49.98 per month for 6 months. Including all parts even main heat exchanger etc.

6 months of cover by Legal & General

Doesn’t cover sludge/scale but then the plan will be fully refunded so no cost

Being sorted on Friday

Very happy
That's what I did and then cancelled after a year.
 
That's what I did and then cancelled after a year.

Did they include replacing the heat exchanger then even though it was damage from limescale? I guess it’s up to the engineer?
Clutching at straws here LOL

and who did you use to install the filter? I see a magnaclean one in screwfix for £80
 
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Did they include replacing the heat exchanger then even though it was damage from limescale? I guess it’s up to the engineer?
Clutching at straws here LOL

and who did you use to install the filter? I see a magnaclean one in screwfix for £80
They installed the filter when they did the repair. Is a magnaclean one. Very easy to use. Said it shouldn't have been installed without one. Not limescale damage is sludge. If you get corrosion in the pipes then there are metal particles in the water which can sludge up the pump or heat exchanger. When you take the filter magnetic element out to clean you can fill up the body with inhibitor to keep the system right. Have had no air or sludge since. I made a fuss as the unit was still very new
 
They installed the filter when they did the repair. Is a magnaclean one. Very easy to use. Said it shouldn't have been installed without one. Not limescale damage is sludge. If you get corrosion in the pipes then there are metal particles in the water which can sludge up the pump or heat exchanger. When you take the filter magnetic element out to clean you can fill up the body with inhibitor to keep the system right. Have had no air or sludge since. I made a fuss as the unit was still very new

How much did they charge you for the filter mate?
 
How much did they charge you for the filter mate?
Can't r,ember exactly. Wasn't much though. You just cut the feed pipe and put the filter inline. Easy extra when the system is already drained for the boiler repair.
 
Can't r,ember exactly. Wasn't much though. You just cut the feed pipe and put the filter inline. Easy extra when the system is already drained for the boiler repair.

Okay I will ask them mate thanks, I’m praying they will fix it on Friday as I’ve had enough lol. Hope they will cover the sludge if that’s the issue
Thanks pal
 
Well Sir,have you had your boiler fixed yet? Hope so! What was the cause of the problem, and is all now ok?
 
Well Sir,have you had your boiler fixed yet? Hope so! What was the cause of the problem, and is all now ok?

Hehe thanks for asking, well... due to this that and the other.. and the engineer being ‘sick’ LOL It’s scheduled for tomorrow... I just want an end to this and be able to have a nice schorching hot shower LOL
 
Vailant Engineer here as we speak, arrived nice and early at 9am. Straight to work with the diagnostic apparatus, fingers crossed :D
 
Finished in just over an hour.

Pump and plate heat exchanger replaced. Excellent service, all parts in van so no waiting. Great!

Very happy especially with the price as I’m covered for another 6 months too, at £300 all in. Really happy.

Abs
 
Well Abs so he changed the heat exchanger and the pump,not sure what model Valiant boiler you have but those with a hours time fitting would be £300 minimum,and could be depending on model £500,so good result
 
Well Abs so he changed the heat exchanger and the pump,not sure what model Valiant boiler you have but those with a hours time fitting would be £300 minimum,and could be depending on model £500,so good result

It’s a Turbomax.

Yeh plus I am still covered for the next 6 months!
 
Update:

The 6 months, £49.98 per month plan is finished.

Now the price has dropped to £28 per month, retaining full cover with Vailant directly.

This also includes the annual service.

Just booked this in and it was hassle free. Very happy, no need to worry about the boiler now :p and we can rest assured it will be repaired properly, first time.

Thanks again for everyones help and the suggestion to contact the manufacturer directly, which I wouldn’t have dreamed of doing otherwise (as its out of warranty and I assumed they’d butcher my wallet). Maybe it’s my experience of Mercedes main dealers? Lol

Regards,
Abs
 
Mah!!!!

Who needs a boiler in the uk. This weather’s gonna last forever surely! :D
 

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