Any boiler experts?

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Call in some one in close to you localy , just to take a look , he wont charge you a lot . And go from there . Do a google on it first .
 
Well I have a idea :) look at your boiler and see where the hot and cold pipes are going,many new systems have gate valves or full bore shut off handles especially heading for showers,if you can turn down the cold valve a little,which will starve the shower and so piping hot water again,
 
Does a combi boiler need system pressure? Dunno?

Our Vailant is a system boiler ( not combi) on mains pressure and if that falls below 1.2bar things go cranky. Top it up using the fill loop. 1.8 seems about right.
 
Well I have a idea :) look at your boiler and see where the hot and cold pipes are going,many new systems have gate valves or full bore shut off handles especially heading for showers,if you can turn down the cold valve a little,which will starve the shower and so piping hot water again,
That will also reduce the flow!
 
I have a Vailant combo and got exactly the same problem. Was dirt in the unit as others have said. Parts replaced and a magnetic filter added and has been fine ever since. The added bonus of the filter is it's much easier to add inhibitor to stop the corrosion in the first place.
 
Today’s boiler are very finely tuned bits of kit and so a filter of some sort is imperative.

I’ve been a plumber for 34 years and that’s roughly all I know about combi’s!!
 
Abs, as others have suggested, I would contact Vailant. They may offer a service which is a fixed fee, may be payable in installments, come out diagnose the problem, fix it, guarantee it, and cover the boiler for a specified time frame, so all future call outs and repairs are also covered within the specified period.
I did just that with a Worcester Bosch boiler, IIRC was circa £250. May sound a lot, but a new PCB was needed, so my payment was well worth it on the initial visit, as I was told the PCB and labour/call out charge would have been more than that in itself, not to mention it was covered for the next 9 or 12 months (can't remember which as it was 4 or so years ago).
I was pleasantly surprised, as not only going down this route made financial sense, you had an engineer who was familiar with the exact model he was working on.
 
Well many new systems do have separate valves on the shower feeds because if and when the shower needs a new cartridge it is easy to isolate the shower so the rest of the house still gets hot water,if it is a combi boiler system or a system boiler,with the latter I have always found that a essex flange and a pump on the hot water tank is the best way to get a power shower,plus if you put valves on the feeds you can as I have said isolate the shower if a combi then you have mains cold water and hotwater from the boiler so by restricting the cold water flow it will make very little difference to the flow from the shower as the hot water is the only one that is pumped,and it would put off the call to the boiler man which in November is twice the price than a call in May.Just a thought just maybe the boiler man turned down the hot water temperature at the boiler and now the cold water feed is much colder the boiler is giving out cooler hot water.
 
Does a combi boiler need system pressure? Dunno?

Our Vailant is a system boiler ( not combi) on mains pressure and if that falls below 1.2bar things go cranky. Top it up using the fill loop. 1.8 seems about right.
Hmm. The pressure is a bit low but I topped it up to half way. Will top it up a bit more and see
 
Hmm. The pressure is a bit low but I topped it up to half way. Will top it up a bit more and see

Don't top it up more than 1.5bar (when cold)

:thumb:
 
I have a Vailant combo and got exactly the same problem. Was dirt in the unit as others have said. Parts replaced and a magnetic filter added and has been fine ever since. The added bonus of the filter is it's much easier to add inhibitor to stop the corrosion in the first place.

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

Thanks
 
Valliant normally quite good and extended guarantee if installed by registered installer.
Try a call to Valliant first.
 
I had a similar issue when I moved into this 3 storey mansion. The drop in temperature was only really noticed when it started getting cold outside. Turned out that is was nothing to do with the boiler.... just the miles of unlagged copper pipe the cowboy builders had ran through the walls and two loft spaces. The only saving grace was we found it before it froze and burst.
 
Spoke to a plumber on the phone, he said sounds like the expansion vesssel, and heat exchanger...

Conveniently the 2 parts not included in the ‘Vailant fixed price guarantee’ FFS!
 
I doubt that it's the expansion vessel. Might be a blocked heat exchanger, though even that seems a bit off. Is it just the hot water that's not right or is it the central heating too?
 
Think about how the things work......just doesn't sound right.

The last time my heat exchanger went it was leaking so the boiler lost pressure and would need refilled.
I changed the heat exchanger myself and got British Gas in right at the back to put it under an all inclusive warranty.
 
I doubt that it's the expansion vessel. Might be a blocked heat exchanger, though even that seems a bit off. Is it just the hot water that's not right or is it the central heating too?

Central heating seems fine
 
Think about how the things work......just doesn't sound right.

The last time my heat exchanger went it was leaking so the boiler lost pressure and would need refilled.
I changed the heat exchanger myself and got British Gas in right at the back to put it under an all inclusive warranty.

The pressure was dropping on mine too but I found a leak in a radiator today and fixed it so. I hope that’s the end of the pressure issue :(

Is it the main heat exchanger that was wrong with yours?

Abs
 

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