Combi hot water flow

EliteHeat

david29dpo wrote: »

Thanks, I understand all that but do any boilers regulate the flow to the temp set on the boiler?

Good grief.

david29dpo

whats with the sarcasm?

EliteHeat

david29dpo wrote: »

whats with the sarcasm?

You have had 6 separate answers to your question. You claim to understand each answer but then re-ask your original question - the same question that was answered by the post(s) you claim to have understood.

I would give up now if I were you, on account of the fact that there are only so many permutations of words that can be used to say the same thing

OK, I'm wasting my time, but I will have one more go ....

• Some boilers regulate the maximum flow of water through them, most don't.
• For boilers that do not, the user regulates the flow of water via the hot taps
• The flow of water determines the temperature of water
• The smallest combi uses less gas & generates less hot water than its bigger brothers.

macman

blackfive wrote: »

David29dpo are you getting confused between the control for the boiler thermostat and the control for the hot water temperature on these combi boilers?

The boiler thermostat control is for how hot the boiler heats up the central heating side of the boiler and the boiler will then cut out when the water for the central heating is up to the set temperature but the pump will continue circulatiing the water if the room thermostat is calling for heat.

The control for the hot water on the other hand specifically controls the heat input into the water for the hot taps. However the faster the flow the lower the temperature will be for obvious reasons.

Combi boilers are good for low occupancy but not for high occupancy as won't cope with the water demands of say, a family with teenage daughters all wanting to wash up, bath/shower and maybe using the washing machine at the same time. A conventional system using storage for hot water can cope with peak demands far better.

As Captain Mainwaring used to say, I think we're getting into the realms of fantasy here...:rolleyes:

Pssst

To summarise, Combis do not sit well together with people who;
Like lots of baths
Have big houses
Have more than one bathroom

If you have any of these,get yourself a high efficiency system boiler and a high efficiency water storage vessel..pressurised if you can run to it/need it.

ormus

normal combis are great. just dont have a bath.
if you really must have a bath, have it at 0200hrs when youre all alone.

Pssst

ormus wrote: »

normal combis are great. just dont have a bath.
if you really must have a bath, have it at 0200hrs when youre all alone.

Indeed and something else to consider.....if you have a combi which say, for arguments sake,has an input of 37 Kw this equates to around 126,200 Btu/hr.

For convenience lets say that nstural gas has a calorific value of around 1013 Btu/hr

This means your combi, on hot water is burning about 126 ft3 per hour.

Consider this...

You live in a street or cul de sac that was built maybe pre 1980. Maybe you live at the extremities of part of the network?

The gas network in your area was probably designed and installed during the "town gas" era long before 37 Kw combis.

Obviously Town gas had a lower CV so there is some gain to be made in heat delivery capacity when using Nat gas.

Now if all your street has had house refurbs and they all have 37 Kw combis,and its cold outside, they might just struggle to deliver the goods as they will all want around 20mb WP at appliance inlet.

I'm a great advocate of stored hot water.

I think way too many combis have been sold inappropriately and for the wrong applications.

rosalie-lavender

Pssst wrote: »

To summarise, Combis do not sit well together with people who;
Like lots of baths
Have big houses
Have more than one bathroom

If you have any of these,get yourself a high efficiency system boiler and a high efficiency water storage vessel..pressurised if you can run to it/need it.

We have a five bedroom house, two bathrooms, three teenagers and I bath every day, we also have a Combi boiler and I wouldn't go back to a conventional system. I really like our combi system. I am not sure how it would compare on running costs though with a different system. Incidentally there is no hot water control knob or external central heating temperature control on ours. If you specifically want that then I would check the boiler you are looking at has them. Our last boiler had both controls and I presumed it was standard until after our new one was fitted.

It is certainly true that you can make a cup of tea while you run a bath though but you get used to it and learn what you can do while it runs. Not much good if you are in a hurry though.

Agree with the poster that said teenage daughters all wanting to wash up is fantasy land, applies to teenage sons too.:rotfl: I presume my son that has just gone to university has discovered the washing up fairy doesn't actually exist.

manda1205

We had a oil fired Worcester (not sure of exact model but its outside too) boiler fitted, we too are noticing the loss of temp if we turn the bath tap hard on, we haven't had a combi before so we werent sure if this was normal or not, but now I see it is. Theres only 2 adults, 1 child in our house and we live out in sticks. We dont run 2 hot taps together as we have no need to. Sometimes though we get a real drop in temp on running a bath to the point you dont need to add any cold, cos its just warm.
Does anyone know if that is normal? Not sure if its just us needing to get used to having a combi or if theres something not right. Sorry to Hijack your thread, but hope someone could answer, thanks.

rosalie-lavender

manda1205 wrote: »

We had a oil fired Worcester (not sure of exact model but its outside too) boiler fitted, we too are noticing the loss of temp if we turn the bath tap hard on, we haven't had a combi before so we werent sure if this was normal or not, but now I see it is. Theres only 2 adults, 1 child in our house and we live out in sticks. We dont run 2 hot taps together as we have no need to. Sometimes though we get a real drop in temp on running a bath to the point you dont need to add any cold, cos its just warm.
Does anyone know if that is normal? Not sure if its just us needing to get used to having a combi or if theres something not right. Sorry to Hijack your thread, but hope someone could answer, thanks.

That is not a problem we have. I reckon to run about a third of the bath cold water before I put on the hot tap and my bath is lovely and warm. Ours is a potterton gas boiler though, not oil fired.