Water is not hot when taps on full - PLEASE HELP! Driving me MAD!

[Loiner_of_Leeds]

Hello, I wonder if anyone can help? I have a fairly large house, combi-boiler feeding about 10 radiators, two showers, two bathrooms. Rarely are all the radiators/showers.baths on at the same time - EVER.
We have to fire the radiators up in order to 'warm' up the water.
The main problem we seem to have is this (and being a busy working family with a toddler, it IS an issue)...
If we run a bath, we have to basically let the tap 'trickle' in order to get any lovely hot water out! This takes about 30+minutes to half fill a bath(!)... If we put the tap on full flow, that water is STONE cold... The same with the shower(s) - we either get up, put the shower on, go and put the kettle on, go for a long walk, whatever... come back 15 minutes later and the shower is just starting to get warm!
As you can imagine, two people getting ready for work in the morning and getting a toddler ready for nursery, it's just not acceptable to waste all this water for such a long amount of time, in order to get a luke-warm 5 minute shower/bath!
I'm 40, lived in loads of different types of places, large and small and up until this house, always managed to put a tap on FULL blast and the water comes out steaming hot! We just can't understand it.
Any plumber we've had always says something like "You need to have your tap on just a little for the water to be hot flowing" – but it just doesn't sit with me, as in my flat of 6 years, once lived in a 7-bed house, my old 2-bed house - all combi boilers, all water flowing fast and hot! I just haven't got the patience to drip feed water into a bath, nor the time with a baby in the house...
Any suggestions? I would do anything for a hot FAST bath or shower! If I can go back to my plumber and tell him the EXACT solution, that would help:)) MANY thanks in advance!

[ummmm]

Same with my old (large) house...We had to turn it on gradually.

[RATTER15]

Sounds like you need a bigger boiler. I work in a huge great house (35 bedrooms) and our water is scolding hot at all points of the house and even when taps are on full.

[Ellipsis]

I used to have this problem when I first moved in to my current house. When I did the house up I replaced the combi boiler with a much beefier model (still a combi) and the problem went away. Your problem is that your boiler simply isn't up to the job...

[HowardKennitby]

^

Sounds like what they said. Can you post the type and model number of your boiler? That might help the experts.

[gingejbee]

Yes, as above - too weedy a boiler for the job. And do you really have to fire up the rads to get some heated water from your taps - not right, surely?

[jomifl]

Not wishing to state the obvious but it seems that the boiler is not producing enough heat either because the gas supply is restricted in the supply (pipe too small, or stopcock partially closed, jet partially blocked) or the control system is malfunctioning or detecting a fault such as restricted air flow. Does this problem still happen with the rads off? It may be too much to expect the boiler to produce a bathful of hot water and heat the house simultaneously.

[The Builder]

Loiner, I guess you've turned the heating and hot water temperature controls up to max? Normally, with a large enough boiler, settings of approx three quarters is about right.
As the others have said, it does sound as though the boiler is underpowered, but .............. before you write it off, have it serviced. Ask the guy to test or replace the thermistors. The boiler could well be ok , but not being allowed to run up to its full temperature because of faulty temp control components.

[Loiner_of_Leeds]

Hi there - thanks for all your replies:))

Just rang my other half - who's at home - it's a:

Baxi Combi 105E (serial no: MBK0403)

The water is even colder when the radiators are off. The radiators being on seems to improve the situation slightly.

The boiler was put in by the previous owner (and he was a cheapskate) so it wouldn't be a surprise if the boiler weren't actually up to the job!

There are three floors (ground, first and second)... (with two further floors [hard to explain... iggeldy-piggeldy Victorian house!] one further upper-floor leading up to a bathroom, one lower-floor leading into the en-suite bathroom) – the boiler is located at the back of the house on the second floor in the en-suite... Not sure if this has any baring on the issue...

I wasn't sure if the fact it's quite a big house (not unusually massive), would also be a factor?? The rooms are very big and the radiators are all miles away from each other. We rarely have all the radiators switched on (only when friends and relatives are staying over)...

We did have a blockage once, but this was resolved by a Brit Gas Engineer. This was the geezer who also did something (whilst my other half was there) that meant the taps can barely be turned on to get a trickle of the rare hot water... before his visit, we could open the (taps) valves a 'little' more!

I (stupidly) thought it might be something simple like increasing the water flow or turning 'something' up... all dials (rad heat/water heat) are up to the max anyway and the pressure sits in the normal range.

Oh, dear.... don't want to have to buy a new boiler ;(( LOL!

[The Builder]

The size of the house will have no bearing on the HW temperature, Loins. HW always takes precedence over CH in most systems. All the combis I've ever had (gas and oil) let you open a tap completely.
Try and find a "proper" heating engineer (most plumbers, quite understandably, can't be expected to keep up with all developments in modern boilers.)
Several minor bits and pieces to eliminate first, before you replace the boiler.

[jomifl]

If you only get cold water from the hot taps when the rads are off it suggests that the sensor that detects that the hot taps are on doesn't detect this state so the boiler only ignites when the rads are on. It may simply be that a wire to/from the sensor has become disconnected or the sensor is malfunctioing. A proper boiler specialist as TB suggests should sort this out fairly quickly. You would be surprised at the things plumbers will do to bodge a problem that they don't understand how the system works. Quite often they make it worse. If you get hot rads then the problem cannot be too serious.

[Ellipsis]

Builder, could you take a look at this link ...

http://www.partsarena...I05-2288/I05-2288.htm

It talks about two modes, a "Central Heating Mode" (section 3.1) and a "Domestic Hot Water Mode" (section 3.2) - it couldn't be as simple as the boiler being in the wrong mode, could it?

Otherwise, Section 4.1 shows the power of this boiler:

4.2 Combi 105e

Appliance Type C12 C32
Appliance Category CAT II 2H 3P
Heat Input C/H & DHW (Gross)
Max Min
kW 34.3 11.9
Btu/h 117,036 40,610
Heat Output Max Min
kW 31.0 10.4
Btu/h 105,776 35,490

Is that enough for the heating requirements of this house - 10 radiators, two showers, two bathrooms?

[Loiner_of_Leeds]

Hi Jomifl - we do get some hot water when the radiators are off, but it's nothing to write home about! LOL! Same problem... just let the tap run for about 10 minutes before the water is sufficiently hot. This 10 mins only applies to the kitchen tap (it's a lot longer for the water to hot up for the bath). Annoying when you want to wash up a couple of mugs and you say goodbye to a few sink's worth of water!

Hi TB - will def get an engineer out this time. Our plumber is a good local chap, but maybe we do need a person who works on boilers specifically day in day out..?

Ellipsis - would be interesting to hear TB's thoughts on your find;)) - thanks

Thanks to you all.

[giveup]

My daughter had this problem and eventually got a new combi boiler. Not only does she now have instant hot water but her water bills have practially halved.

[Loiner_of_Leeds]

Hi GiveUp,

That's one of my main arguments, too - the water! It's SUCH a waste! I hate wasting water for apparently no good reason:)

I should be able to open a tap on fully and get very hot water within a few seconds, but the Brit Gas Eng CONVINCED my other half that this WAS NOT possible and that we need to 'drip-drip-drip' the water into the bath/sink at a snail's pace in order to get piping hot water! Had I have been there, that wouldn't have (pardon the pun) washed with me!

Never had this problem prior to living in my current house, whereas my other half has only had one other place - so not much to compare it to... whereas I've lived in loads of places - so I know it's not right!:))

[The Builder]

Well Ellipsis, that link goes a long way towards de-mystifying the subject doesn't it? Very clear.
What you say certainly makes a lot of sense. Loiners' problem does rather look as though the boiler can't make up its mind which job it should be doing ..... result being somewhere between the two.
So, .............. diverter valve (sends water to either CH or HW) faulty/sticky?
Simple little flow sensors that determine when the heating is satisfied - faulty?
Temp sensors - simple devices that could mess everything up if faulty.

Most difficult item to check (except for simple substitution) is the circuitboard. The various sensors may be ok, but the board is not implimenting the data properly.

I agree that it does look like a mode-related problem.
Anyway, the diverter valve is electro-mechanical, so not difficult to test. They have been known to respond to a bit of a whack!
Replace/test a few flow sensors/temp sensors/thermistors etc before moving on to circuitboard and other more costly items.

[Loiner_of_Leeds]

THANKS VERY MUCH both TB and Ellipsis, and ALL of you really... Obv the boiler is not coping very well and needs a good seeing to (I have been know to whack things, but...)! I will get our engineer to try the things you've said before moving on to more costy stuff!
Cheers guys, thanks again and have a good day:))

[The Builder]

Pleasure, Loins. Do let us know how it turns out :o)

[Ellipsis]

Loiner, now I'm home I have just checked the power rating (max heat output) of my own boiler (a Baxi 130HE) and the numbers look similar to your Baxi 105E. My house also has 10 radiators, a bath and and two showers so you should be fine with your current boiler if you can get it working ...

[Loiner_of_Leeds]

Hi there,
Heating Engineer at home right now (I'm at work) - will let you know the outcome... Just to say; I don't want all the taps on at once (lol!) - Just one tap, on full, would be nice! ...watch this space!