The combi debate continued .........

[gasbanni]

Cont .......

The combi was originally designed from instantaneous water heaters.

On a hot water demand combis still modulate.

You don't have to heat a cylinder up with a combi to do the washing up !!!!!

In most instances a combi is the best choice or perhaps a combi and an unvented then you've got the best of both worlds. But I wouldn't recommend that for a normal three bedroom semi.

I've installed this type of set up where they have three bathrooms, the combi produced hot water for a kitchen and downstairs utility with a shower room. Far better set up than having all the hot water draw off from the cylinder. They always have hot water available in the kitchen.

The combi does have a lot going for it, obviously not in every instance. Heat only boiler and a multipoint now there's a reliable set up !!!! And the multipoint doesn't need electricity and they modulate !!

 

[Roger928]

And the multipoint doesn't need electricity and they modulate !!

What are those? Have you a link?

 

[bernardgreen]

The efficiency when supplying hot water for washing up can be very low

Building Research Institute tests

Measurements of gas volume used and cold water run before hot water comes out of the boiler are being carried out by another research group. Early results suggest that over all efficiency is higher with a cylinder heated by a single but prolonged burn per day.

 

[Bodd]

They have thier purpose. Efficient is not the only concern for the home owner. It is the extra space created less risk of flooding for needlessly fitting tanks in the loft.
Unfortunately any monkey can fit one regardless if the water or Gas supply’s are adequate.

I get very few call backs to the ones I fit. They are a lot more reliable than they used to be and Some come with big warranty’s.

 

[Roger928]

They have thier purpose. Efficient is not the only concern for the home owner. It is the extra space created less risk of flooding for needlessly fitting tanks in the loft.
Unfortunately any monkey can fit one regardless if the water or Gas supply’s are adequate.

I get very few call backs to the ones I fit. They are a lot more reliable than they used to be and Some come with big warranty’s.

How do you couple solar energy with them?

 

[Bodd]

How do you couple solar energy with them?

Well that would be PV. Not really a benefit

 

[Roger928]

Well that would be PV

No.
Solar tubes and panels. I expect it can't be done.

 

[JohnD]

If you have gas and a HW cylinder, the cost of gas to heat it in summer is trivial.

A solar power diverter for the immersion heater costs about £250, and does not have a realistic payback, because the savings in gas cost are negligible.

For people who have to heat the HW electrically, solar PV panels or warm tubes may be worthwhile, and no need for a power diverter.

 

[gasbanni]

What are those? Have you a link?

Unfortunately they're a dying breed, I don't think you can buy a new one anymore.
Quite honestly they were one of the best gas appliances ever designed .....considered a dinosaur by young gas fitters .......I once got called to one ...never stopped working in 18 years hadn't been serviced ....didn't need servicing clean as a whistle new diaphragm working again, so it's efficiency wasnt like a new appliance. But it's carbon footprint Ilk bet was far less than new condensing boilers!!

 

[Roger928]

I don't think you can buy a new one anymore

Fat lot of use that is then.

 

[gasbanni]

Yes it is if you've got one keep it !!
The ones you can get now are fan flued .....

Oh sorry You can still get them Main still do them ! I haven't worked on one for ages.
If you have a main one installed the replacement just bolts on the existing flue.

 

[ReganAndCarter]

What are those? Have you a link?

https://www.plumbnation.co.uk/site/...MI-repitmC2wIVxm4bCh0VugmAEAQYASABEgJLafD_BwE

Or a Rinnai.

Or is Gasbanni referring to an Ascot?

 

[gasbanni]

The efficiency when supplying hot water for washing up can be very low

Building Research Institute tests

View attachment 141714

Measurements of gas volume used and cold water run before hot water comes out of the boiler are being carried out by another research group. Early results suggest that over all efficiency is higher with a cylinder heated by a single but prolonged burn per day.

In practical terms you want water hot enough to disperse the grease. Irrespective of the building regs. Combi = virtually instant hot water. Takes some beating, hot water cylinders have their place...but not very often . Just accept it.

 

[Bodd]

Yes it is if you've got one keep it !!
The ones you can get now are fan flued .....

Oh sorry You can still get them Main still do them ! I haven't worked on one for ages.
If you have a main one installed the replacement just bolts on the existing flue.

Yes we had an old Ascot

 

[ReganAndCarter]

They're still available.

https://www.ebay.co.uk/itm/Ascot-Water-Heater/392042675146?hash=item5b47907bca:g:5E8AAOSwKOJa7e9e