Combi Boiler - how long should I have to wait for hot water?

PinkFloyd

PinkFloyd

PinkFloyd

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I've recently had a new Combi Boiler fitted (Worcester Greenstar 25SI Compact) to replace an ~18 year old British Gas C1 that failed and currently I'm not overly impressed.

When I turn the kitchen hot tap on, I can have the water running for up to 30 seconds before the boiler fires and starts actively heating water. Until then I just get waves of hot and cold water, presumably some warmth from residual heat in the boiler? The tap is around 2 metres from the boiler, maybe 3-4 metres of pipe in total, I never had this issue with the previous boiler that would fire almost immediately.

I also seem to constantly be having to bleed the radiators since the change so I'll be calling up the company that did the fitting work to get their thoughts, I just wanted to get a bit of guidance on what's considered normal on a new boiler?

Any help would be hugely appreciated!
 
Was gonna ask how far it is from the boiler.

My boilers in the loft resulting in having to let the down stairs taps run to get hot water.

Are you sure it comes straight from there and not some convoluted route up to where the boiler used to be and back down etc
 
Had a new boiler fitted in August, hot in the kitchen after about 10 secs and it goes up to the bathroom first and back down again boiler fires immediately

Rads needed bleeding couple of times and boiler pressure topping up but it's been fine in that regard ever since

On mine there is a setting that can delay when it fires for hot water on demand, maybe it's set incorrectly on yours but mine is a different make

I would definitely be contacting the installer doesn't sound right
 
my Worcester Greenstar has an eco option that turns off a pre-heat hot water function making it more economical but a longer wait for hot water
 
kitchen with adjacent combi boiler(no-tank), that is cold (pre-heat off/central heating off), fires < 5s, but will be 10L of water/40s before is hot for washing up, with pre-heat on more like 5L / 20s.
.... so depends on pre-heat/CH
bathroom upstairs <20m maybe 18L/80s
 
As above, sounds like EcoMode is on. Turn it off, so that you have pre-heat for the water enabled.
Though 8.9l/min at 40c doesn't sound much. I'd also look at the water temperature the boiler is set to.

The radiators shouldn't need 'constant' bleeding though. I had a new boiler (also moved to the loft), and all new radiators. I think it's been bled once about a week after it was all installed.
 
Hi All, thanks for the prompt responses! Eco/preheat modes definitely seeming like they're part of the issue here. The fitter mentioned enabling Eco mode to stop it constantly keeping a small amount of hot water ready to go to save gas, which sounded like a good thing, but if that's actually stopping the boiler firing up quickly when I actually want more than a splash of water it's annoying. I've disabled Eco and will see how much of a difference it makes. Water temp is set high, around 55 degrees from memory.

Don't think there is a convoluted route to the kitchen sink, but I guess there could be pipe work running alongside the soilpipe to/from upstairs where there used to be an immersion heater in the loft. Although if that was the case I'm sure I'd have had a similar issue previously. Also when I run the hot taps upstairs I can definitely hear expanding/banging in the pipes in this column, which I don't get on the downstairs top.

As for the radiator bleeding, maybe I'm not doing a proper job of it so needing to do it again and again? I'll do some research :D
 
I've always had the eco mode enabled on my combi. It fires up as soon as the tap opens and there's no big delay in getting hot water. I have to pull off the standing water in the pipes from the loft, but that'd have to happen even if eco mode wasn't on.
 
It should fire almost immediately on opening a hot water tap regardless of whether its in Eco mode or not.
Are you sure it doesn't fire for 30 secs or presuming as that's how long it takes before providing constant hot water ?
Is your cold water pressure to the boiler good ?
If yes to both of the above I would be looking at the DHW flow sensor.
 
My combi isn't instant, but it lives in the garage, if the CH is running though, it comes through hotter, sooner.
 
Agreed, sounds like a sensor or config issue to be honest. Ours takes 10 to 15 seconds from turning a completely cold tap on to hot water flowing, and thats coming from the garage with no preheat or anything.
 
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