In praise (faint) of combi boilers

[Dan B]

This flat is the first place I've ever lived with a combi boiler that claims to heat water on demand. My finding so far is that (a) I have to run an an entire basin of lukewarm water before it gets hot, (b) a couple of minutes later it may arbitrarily decide I have had enough hot water and go back to cold - which makes the occasional bath a less than special occasion; (c) to add insult to injury, the central heating doesn't seem to have enough oomph (however these things are measured) to heat the whole flat at once: to get the living room radiator to radiate requires turning several of the others off.


Is this normal, or is my boiler underspecified for the dwelling size, or is it in some way shagged? Either of the latter two diagnoses would come as no surprise, tbh

 

[colly]

I had a combi boiler fitted about 2 years ago. No problems at all with enough hot water at mains pressure and it heats the house up in no time at all and keeps it warm.

It could be yours is too small or simply needs a service and or adjustment.

 

[bobg]

This flat is the first place I've ever lived with a combi boiler that claims to heat water on demand. My finding so far is that (a) I have to run an an entire basin of lukewarm water before it gets hot, (b) a couple of minutes later it may arbitrarily decide I have had enough hot water and go back to cold - which makes the occasional bath a less than special occasion; © to add insult to injury, the central heating doesn't seem to have enough oomph (however these things are measured) to heat the whole flat at once: to get the living room radiator to radiate requires turning several of the others off.



Is this normal, or is my boiler underspecified for the dwelling size, or is it in some way shagged? Either of the latter two diagnoses would come as no surprise, tbh

Mine did all those things till last week when a local firm recommended that I replace the heat exchanger ( whatever that is ) Its wonderful now!!

 

[marinyork]

This flat is the first place I've ever lived with a combi boiler that claims to heat water on demand. My finding so far is that (a) I have to run an an entire basin of lukewarm water before it gets hot, (b) a couple of minutes later it may arbitrarily decide I have had enough hot water and go back to cold - which makes the occasional bath a less than special occasion; © to add insult to injury, the central heating doesn't seem to have enough oomph (however these things are measured) to heat the whole flat at once: to get the living room radiator to radiate requires turning several of the others off.


Is this normal, or is my boiler underspecified for the dwelling size, or is it in some way shagged? Either of the latter two diagnoses would come as no surprise, tbh

One of the houses at university did all of that. Really wound me up, might as well have ripped the whole lot out (we live in a mild climate) and not had any central heating and saved a fortune in cash each year.

A mate who has a combi boiler has a very long cable run and their gas bills actually went up and not down, despite the boiler should be much better as it's far more efficient. A bloke across the road from them with an identical boiler fitted around the same time it works fine.

 

[Maz]

The efficiency of the boiler will depend on a number of factors, e.g.
The rating of the boiler relative to the volume of the rooms required to heat.
Whether the piping is lagged (if it runs along external walls/cold temps., etc)
Age/type/size of radiators and if they are the right size for the room
Water pressure
Temperature setting on the boiler, etc

 

[subaqua]

One of the houses at university did all of that. Really wound me up, might as well have ripped the whole lot out (we live in a mild climate) and not had any central heating and saved a fortune in cash each year.

A mate who has a combi boiler has a very long cable run and their gas bills actually went up and not down, despite the boiler should be much better as it's far more efficient. A bloke across the road from them with an identical boiler fitted around the same time it works fine.

Cable run ?? do you mean pipework.

in answer to the OP I suspect its shagged. and the symptoms do sound like

a) heat exchanger
b) temp sensor
c) diverter valve fault

get a Gassafe registered fitter/engineer to have a look at it.

 

[PaulSB]

We had a combi boiler fitted in April and it's marvellous though for the first ten days or so I was worried. We had similar difficulties to those you describe. I read all the instructions very thoroughly, got to understand all the different settings, and over a few days worked out what suited our house. With our old boiler the system was simply on or off, the combi seems to require more than this. Water temperature, rad settings, operating temp etc all need to be balanced. Also check the radiator valves are correctly set.

Our gas bills have dropped by 60% in six months though I await the winter one with interest. EDF didn't believe our readings till I explained we had a new boiler.

Our thermostat is wireless and can be moved round the house. We also did this until we found the spot which gave us the best result.

 

[subaqua]

We had a combi boiler fitted in April and it's marvellous though for the first ten days or so I was worried. We had similar difficulties to those you describe. I read all the instructions very thoroughly, got to understand all the different settings, and over a few days worked out what suited our house. With our old boiler the system was simply on or off, the combi seems to require more than this. Water temperature, rad settings, operating temp etc all need to be balanced. Also check the radiator valves are correctly set.

Our gas bills have dropped by 60% in six months though I await the winter one with interest. EDF didn't believe our readings till I explained we had a new boiler.

Our thermostat is wireless and can be moved round the house. We also did this until we found the spot which gave us the best result.

our gas bill is great. we pay by DD so build up a winter surplus which we then eat into when its particularly cold. we have gone from £40a month to £20 a month since we got the combi. you are right that setings need to be tweaked for the heating but the OP is complaining about hot water from the tap.

 

[Dan B]

I can complain freely about both - here I am sitting in the living room wearing nearly as many layers as I do for an fnrttc - but it was my attempt yesterday to take a bath that triggered this particular rant. Thanks for all comments, and yes it does sound like it's not supposed to be this way. Time to hassle the landlord

(Cold water pressure is fine, btw. Visitors to our house have no problem inadvertently spraying themselves with water that ricochets off the bottom of the kitchen sink when they turn the tap on)

 

[marinyork]

Cable run ?? do you mean pipework.

Yes. The boiler was moved on the orders of the nomenklatura and so meant a much longer run.

 

[Norm]

Hmm... a combi boiler, huh? You may remember, from the shaving thread, that similar issues with a combi are what lead to me shaving in cold water for 3 or 4 years.

 

[Aperitif]

Keep the faith Dan - make sure the pressure is at 11/2 Bar - or whatever, for your system and it will save lots of money.
you may shiver to pieces but the new year will bring riches...

 

[User482]

British gas are at my house, right now, for the second time in three days. It seems I have a rubbish combi and a rubbish engineer.

 

[threebikesmcginty]

British gas are at my house, right now, for the second time in three days. It seems I have a rubbish combi and a rubbish engineer.

It would've been better if they sent a heating engineer I guess, still while he's there he could empty the bins.

 

[User482]

It would've been better if they sent a heating engineer I guess, still while he's there he could empty the bins.

I'm not convinced though - have you ever used British Gas?