What might make combi produce low dhw flow?

[WaterTight]

Mum just moved into new place. I am not GSR but can do rest plumbing. She has a logic 24 combi. Hot at all outlets flow resembles what you might get from a fortic in a flat. Boiler fires fine, water gets hot, just poor flow. Cold is fine/normal. Is this something a gas safe guy will have to investigate/fix or something I can look at?

Thanks

 

[Chalked]

24 kw is about 9 litres a min.
Might look poor through a bath tap. Measure flow into a jug and time it. That will give you litres a minute. Bet it's not far off.

 

[WaterTight]

It's the lowest flow I've ever seen on a combi and have worked on taps on hundreds of combis. I would guess from checking it out it would be maybe 4 litres a min tops.

 

[townfanjon]

Yep dont expect much out of a 24 KW

 

[townfanjon]

It's the lowest flow I've ever seen on a combi and have worked on taps on hundreds of combis. I would guess from checking it out it would be maybe 4 litres a min tops.

Bloody hell lol

 

[WaterTight]

tbh she's not fussed but doesn't seem right to me and if it was a reasonably simple fix, even if needing a gas safe chap I'd recommend it for her. Just want an idea.

 

[ShaunCorbs]

dont know if they have but check the strainer

 

[Harvest Fields]

Is your mum in a hard water area?

 

[Scott_D]

Are flow restrictors fitted?
Could be the strainer partially blocked?

 

[WaterTight]

As said, not GSR so no knowledge about boiler parts/workings.

Would the strainer be this thing on the right? And how do I 'check' it?

It is a hard water area yeah. Not sure if flow restrictors are fitted or where I would check that, unless you mean at/on the taps?

 

[Chalked]

Probably scaled up heat exchanger

 

[Scott_D]

The strainer is inside the boiler
Flow restrictors may be inside the isolation valves for each tap

 

[Harvest Fields]

Probably scaled up heat exchanger

That's where I was heading, could even be a scaled up inline scale reducer. The long chrome thing on the left. Or has someone part turned off the flow valve to the boiler?

 

[WaterTight]

Would a scaled up inline scale reducer just reduce hot flow, normally? I can check that one.

I can't do anything within boiler as not GSR.

Will check there aren't flow reducer on iso's to taps.

Given the boiler then if I managed to increase the flow would it suddenly struggle to keep water hot if taps turned on too much? At the moment water nice and hot. As I said my mum isn't too bothered and don't want to swap one problem for another but would like to increase her hot flow if I could, mainly because filling a bath would currently take a month.

 

[WaterTight]

Oh and is the "flow valve to the boiler" something I can check not being GSR?

 

[townfanjon]

WT , yep bin the scale reducer ( at least for now) , only other thing is the flow turbine in the boiler could be prone to crud , but you would need to go in the boiler for that .

 

[joni os]

Divide the Kw rating of boiler by 3 to get expected flow in litres/min.
24Kw should give 8 litres/min. If you can confirm cold water flow to boiler exceeds 8 litres/min then problem is most likely scaled up domestic hot water heat X. Could be faulty diverter valve but in hard water area any heatX more than 6 years old is worth replacing even if problem is elsewhere. Need to be GSR.

 

[WaterTight]

Very helpful. Thanks all.

 

[king of pipes]

I had one with a similar problem i had to strip down the whole hyroblock and clean it out as it had not been used for over a year there was a obstruction once removed all was ok 9-10 litres a minute regards kop

 

[WaterTight]

The house had been vacant for a couple of months. Not sure if that could be a factor?