Recommend a 24kw Combi

[hard-work]

Bernard, an ATAG with flue heat reclaim is very efficient indeed in DHW. You can get a super insulated cylinder that wastes little heat, but they cost. And they take up space and have complex controls on them looking like a space capsule. Read what I wrote. Overall a high flow quality combi beats a cylinder any time, when all aspects are taken into account. In small British homes, and boy are they are small, why would anyone put in a space consuming cylinder when there is no need to do so? It is madness to go that route.

An Intergas and Ferroli Modena combis do not even use the pump in the summer, saving electricity. They spin it for a few seconds once a day to prevent seizure.

 

[Dan Robinson]

Can you expand on that ?

I know you don't agree with the BRE report.

You are being fairly balanced and I've no fan issue with anything you've written. However with you and That other muppet feeding of one another this thread only had one trajectory.

 

[bernardgreen]

And they take up space and have complex controls on them looking like a space capsule.

A vented cylinder does not need to have so many safety devices.

I agree that modern compact "home" desigms do not provide space for a cylinder, but that is likely to change. It may not happen in the very low cost end of the housing market where build cost is critical in getting sale price as low as possible. Architects ( or building design technicians ) are seeing how poorly a combi performs, often this is in feed back from tenants / owner occupiers to the developers who built the houses.

Please do not be rude or derogatory about Dan Robinson. He is an experienced heating engineer and while he and I do not always agree his opinions are valid.

 

[bernardgreen]

only had one trajectory.

True but my aim was to put the other case to the general readership.

 

[hard-work]

A vented cylinder does not need to have so many safety devices.

I agree that modern compact "home" desigms do not provide space for a cylinder, but that is likely to change. It may not happen in the very low cost end of the housing market where build cost is critical in getting sale price as low as possible. Architects ( or building design technicians ) are seeing how poorly a combi performs, often this is in feed back from tenants / owner occupiers to the developers who built the houses.

Please do not be rude or derogatory about Dan Robinson. He is an experienced heating engineer and while he and I do not always agree his opinions are valid.

Sorry Bernard, I have read Doddy on a number of occasions and he falls short. He is an insulting *******. The insults come out when points are out of his range. But he is fun. So do not take him seriously.

Bernard, homes are getting smaller. But that is beside the point. A good, high flow, quality, combi beats a cylinder any day. Defending needless cylinders is like those Luddites who defend internal combustion engine cars over EVs. They have no case but constantly droll on and on and on. Even when proven wrong, their minds cannot grasp it, they are so conditioned or just plain not bright people.

Get out of this, "we always do it like this." Read my post again, especially on how to pipe a combi up. In mains pressure systems, shower is king, all flow and pressure must prioritise towards the shower. Once that is understood it is much easier, with a nice system giving no problems to the homeowner.

Those who complain about combis generally have a model which is too small for the DHW and/or not piped up properly.

 

[hard-work]

Bernard, the days of baths are receding. Many new homes have walk-in showers, many with double shower trays with no doors. Many rip out baths and fit walk-in showers as I did. Older people prefer walk-in showers rather than slipping in baths causing injury. A 90 year old neighbour just slipped in his bath - not nice. In walk-in showers they can just put a plastic chair in there if they need to sit. A high flow combi does these showers very well.

Gledhill listened to architects and came out with the thermal stores that do not need discharge pipes or overflows and no chance of explosions. This meant the store can go anywhere in a home not just on an outside wall. This gave architects greater scope for internal design of a home. A combi gives that flexibility as well.

 

[hard-work]

A vented cylinder does not need to have so many safety devices.

Bernard? Now stop that.

 

[JohnD]

Many new homes have walk-in showers

possibly because many new homes are designed to be cheap and tiny.

I am not convinced that British people prefer a home with no bath.

 

[hard-work]

possibly because many new homes are designed to be cheap and tiny.

I am not convinced that British people prefer a home with no bath.

Walk-in showers are not cheap. The mood is changing towards walk-in showers. Fitting one was one of the best things I ever did.

 

[JohnD]

Walk-in showers are not cheap.

but tiny homes are. Relatively.

possibly because many new homes are designed to be cheap and tiny.

 

[hard-work]

but tiny homes are. Relatively.

You do have a point. But even in large homes walk-in showers are what people want. They are a great attraction to sell.

 

[bernardgreen]

Older people prefer walk-in showers rather than slipping in baths causing injury. A 90 year old neighbour just slipped in his bath - not nice. In walk-in showers they can just put in a plastic chair in there if they need to sit. A high flow combi does these showers very well.

Have you heard of cold shock and the effect it can have on people. Mostly it happens when people fall into cold water, but can and does occur when the temperature of the shower water drops suddenly. Person in shower, someone opens another hot tap fed from the same combi....with a cylinder feeding the shower the rate of change of temperature is slow

http://www.coldwatersafety.org/ColdShock.html

Threat No. 2
Heart and Blood Pressure Problems
Cold water immersion causes an instantaneous and massive increase in heart rate and blood pressure because all the blood vessels in your skin constrict in response to sudden cooling, which is far more intense in water than in air. In vulnerable individuals, this greatly increases the danger of heart failure and stroke.

 

[hard-work]

Have you heard of cold shock and the effect it can have on people. Mostly it happens when people fall into cold water, but can and does occur when the temperature of the shower water drops suddenly. Person in shower, someone opens another hot tap fed from the same combi....with a cylinder feeding the shower the rate of change of temperature is slow

http://www.coldwatersafety.org/ColdShock.html

Bernard, read my post on how to pipe up a combi system. I can be in my shower and the daughter turns on the kitchen tap. A slight glitch is felt in the flow, not temperature, that is all. I have 6 litre per/min regulators on the hot and cold of kitchen sink taps. It works very well indeed. All the flow I need. It does not affect the shower greatly. The shower is prioritized to take flow and pressure. Easy to do.

If it is as severe as you say, the combi is too small and/or it is piped up wrong. Having your head smashed against a tiled wall is not nice when slipping in a bath.

 

[John D v2.0]

You can get a super insulated cylinder that wastes little heat, but they cost. And they take up space and have complex controls on them looking like a space capsule. Read what I wrote.

I thought I was the only one with a phobia of space capsules, turns out it's a compelling argument against hw cylinders?

 

[hard-work]

I thought I was the only one with a phobia of space capsules, turns out it's a compelling argument against hw cylinders?

You have a valid point. But there are many other more compelling arguments against these projectiles. If it is an unvented cylinder that goes wrong it could be a projectile. Maybe they should have the word NASA down the side of them.

We could kid the Ruskies every home has a nuclear weapon ready to launch against them