Downstairs hot tap not firing up boiler.

I wanted to rule out a faulty new sink mixer tap...ie. when you open the hot tap they could be a possibility that water is drawn across the mixer from the cold side and an insufficient amount from the hot pipe.
 
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The manual indicates the boiler should come on with a flowrate exceeding 3 litres/min.
I would check the cold inlet valve under the boiler is fully open and if so check the turbine and the combined filter and flow limiter in the turbine inlet connection. Probably worth pulling out the flow limiter and blowing through the turbine to check it spins freely.
 
I've uploaded pics of the tap and the pipes feeding the tap chaps. However, I've made my mind up that I'm getting a new boiler. I've had a few problems with this one over the last few years to be honest - expansion vessel has gone, twice. PRV has gone. Condensate pipe has cracked underneath and the flue outside is dripping water outside directly above the kitchen door, which often drips on my head and freezes up on the step in the winter, and I've almost broken my neck slipping on it. Enough is Enough. This latest leak i've had has caused me to put a hole in the ceiling in order to find the leak.

What I need to know is whether a new boiler will be triggered by this tap at a flow rate of 4 litres/min? If you guys have any recommendations for which model I should go for then I'd appreciate the advice. Although it's tempting to just carry on with this boiler, I have a strong feeling that I'm just delaying the inevitable.

One thing I have just discovered though is that if I restrict the cold tap flow using the isolator then this has improved the flow rate on the hot side of the mixer slightly? Does this sound feasible?

Thanks in advance guys, all your advice is much appreciated!
 

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The manual indicates the boiler should come on with a flowrate exceeding 3 litres/min.
I would check the cold inlet valve under the boiler is fully open and if so check the turbine and the combined filter and flow limiter in the turbine inlet connection. Probably worth pulling out the flow limiter and blowing through the turbine to check it spins freely.

Where could I find a manual? that would be VERY useful!
 
I don't know any combi boiler that needs 4 l/ min + to trigger a demand for DHW .
You need to establish ....
1. Why your flow is so poor.
2. Why your boiler doesn't fire up with the flow you have ,when clearly it should .
As Gasguru and I have pointed out ,the parts within the boiler that can affect the flow to the taps ,and their correct functioning to activate the boiler ,need investigation.
What is the flow rate of cold water only from the kitchen tap ?
Boiler manuals can be downloaded from various sites.
 
I don't know any combi boiler that needs 4 l/ min + to trigger a demand for DHW .
You need to establish ....
1. Why your flow is so poor.
2. Why your boiler doesn't fire up with the flow you have ,when clearly it should .
As Gasguru and I have pointed out ,the parts within the boiler that can affect the flow to the taps ,and their correct functioning to activate the boiler ,need investigation.
What is the flow rate of cold water only from the kitchen tap ?
Boiler manuals can be downloaded from various sites.

Hi Terry,

The Guy who fitted the kitchen mentioned that I had poor mains pressure, so I've no idea how that could be fixed. I don't think I have any control over the pressure coming in. I am getting a decent flow out of the shower upstairs, but its DEFINITELY not getting as hot as it used to. I used to have to have it resting on it's limiter on the thermostat, but now I have to turn it right the way up to get it hot enough, and even then its lukewarm.

I'm just thinking that the boiler must be just worn out and is giving up the ghost?

The flow rate from the cold side of the mixer tap seems a bit stronger than the hot side, so I've adjusted it on the isolator so the cold is now a bit LESS than the hot, and to be honest it appears to have made a difference. The boiler seems to be kicking in every time I turn the hot side on now. I'm not sure if this is just a fluke, but honestly it seems to be kicking in every time now.

It's very probably just luck though, and bugger all to do with what Ive adjusted.
 
The manual indicates the boiler should come on with a flowrate exceeding 3 litres/min.
I would check the cold inlet valve under the boiler is fully open and if so check the turbine and the combined filter and flow limiter in the turbine inlet connection. Probably worth pulling out the flow limiter and blowing through the turbine to check it spins freely.

Thanks Gasguru, but I'm not sure Im qualified to take out the flow limiter. Is that something I could do easily?
 
:rolleyes::rolleyes::rolleyes::rolleyes: I didn't notice it's a Greenstar version of the 28i....
Worcester don't appear to quote a minimum flowrate for the DHW to kick in on these models.
You should not remove the outer casing to access the turbine as it forms part of the safety system of the boiler.
 
Hi Terry,

The Guy who fitted the kitchen mentioned that I had poor mains pressure, so I've no idea how that could be fixed. I don't think I have any control over the pressure coming in. I am getting a decent flow out of the shower upstairs, but its DEFINITELY not getting as hot as it used to. I used to have to have it resting on it's limiter on the thermostat, but now I have to turn it right the way up to get it hot enough, and even then its lukewarm.

I'm just thinking that the boiler must be just worn out and is giving up the ghost?

The flow rate from the cold side of the mixer tap seems a bit stronger than the hot side, so I've adjusted it on the isolator so the cold is now a bit LESS than the hot, and to be honest it appears to have made a difference. The boiler seems to be kicking in every time I turn the hot side on now. I'm not sure if this is just a fluke, but honestly it seems to be kicking in every time now.

It's very probably just luck though, and bugger all to do with what Ive adjusted.
Altering the flow on the cold to the tap ,without any pressure change ,can't really make any difference to the boiler firing up. Are you really Anti the idea of getting an engineer to visit ?
 
Altering the flow on the cold to the tap ,without any pressure change ,can't really make any difference to the boiler firing up. Are you really Anti the idea of getting an engineer to visit ?

Not at all! I'd welcome a good engineer! I'm not sure if I mentioned it, but I've actually had an emergency boiler engineer out who diagnosed a leak on my boiler which was coming from the PRV valve, but instead of dumping it outside out of the little copper pipe, it was leaking inside and has leaked that much that i now have a hole in the kitchen ceiling. He's coming back to fit a new expansion vessel on tuesday as well as a new PRV valve and he's going to replace a piece of cracked condensate pipe, which was also leaking. I asked him about the tap downstairs and he blamed the flowrate even though he hadn't measured it, and suggested I should get a 'large bore' isolator on the hot supply. He wasn't really interested to be honest.

I have a £500 limit on my emergency boiler cover and I've been told that I've almost reached that by getting these new components fitted. It's not actually coming out of my pocket, just out of my insurance allocation of boiler repair money, if you know what I mean.

Ad far as I can work out (an I am a manufacturing Engineer by trade) then if I'm getting a flow of 4 litres/min on the hot side and the boiler isn't firing then it must be some kind of flow sensor issue. Maybe some kind of diaphragm that detects a small pressure change or something? All I know is that I need a reliable boiler, and after 15 years (mostly of neglect, if I'm honest!) then it's almost certainly time to start thinking about a new one.

Like, why on earth would the PRV valve blow off INSIDE the house? I don't get it? I've totally lost confidence in this boiler because I've now got a very unsightly hole in the ceiling and need a plasterer as well to patch that up!
 
Turn off the isolater to the cold side of the tap try it then. Faulty tap if the boiler then fires up.
 
Ok ,sounds like you have had enough of " Junior" !! 15 years ain't a bad age to have lasted ,given the fact that you have neglected it somewhat .
But changing the boiler isn't going to improve the taps performance.
 

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