can we change to a combi?

[Doctor Drivel]

We have recently moved to a house with an ancient floor mounted Baxi Boiler (FS601 OF). It works fine, but we would like to change it for something more energy efficient. However, we have been told by a plumber that it could be a problem fitting a combi if we have a single pipework system, without changing all the pipework (and possibly rads. too). How can we tell? and what sort of boiler would suit if a combi is such a problem? Hope you can help. Thanks.

Combis are the same as normal non-condensing or condensing boilers, except the have a simple water section.

If the pipework is a one pipe you have problems with any type of boiler not just a combi. The one-pipe system "may" have to be converted to a two pipe setup. It can be kept by having a gate valve in the upstairs and downstairs rad circuits. Then throttle back to slow the flow to allow flow through the rads. One-pipe systems don't like high flows as the hot water by-passes the rads. One pipe systems are not good for condensing boiler system either - modern boiler have to be condensing.

Combis score in eliminating tanks and cylinders and giving instant DHW for ever.

Look at the Ethos combi, they are highly cost effective.
http://www.ethosboilers.co.uk/products_54c.php
It actually gives 23 litres/min @ 35C temp rise, capable of supplying two bathrooms. It takes an OpenTherm room temp controller. The Honeywell Cronotherm will do. It modulates the burner via the controller.

It also keeps the DHW heat exchanger warm too (user selectable). The DHW heat exchanger is a coil of copper pipe with three small pipes inside that. The temperature sensors just clip on the pipes in he boiler, so easily serviced as no drain downs. It also has an outside weather sensor as well.

They sell between £1,200 and £1,300 inc' delivery plus VAT. They are cheap for what they are. A floor mounted W-Bosch Highflow 440 goes for £1,550 and drops off in flowrate when the store is depleted. The Ethos 54C is an infinitely continuous combi - never runs out of DHW and the flowrate never drops too. Great for body jet showers, where many have to spend a fortune upgrading cylinder sizes when fitting them as they run of water quickly. These never run out.

Designed in the UK, and made in Holland. They use a Giannoni heat exchanger, Grundfos pump and Honeywell 3-way valve. It is a commercial boiler downsized for domestic. The case is small too for the output. It is not like the Vaillant ecoTEC937, which is the size of a washing machine on the wall. This along with the MAN Micromat (ECO-Hometec) are about the best high flowrate infinitely continuous combis around.

You can fit a secondary DHW circulation loop with it giving instant DHW at the taps. They sell a kit, or make it up yourself using check valves and a bronze pump.

The only down side is that it only modulates down to just under 10kW.

If you want backup have an in-line instant electric heater. Switched off normally and the DHW from the combi runs right thought it. Switch on and temporary DHW.

Take no notice of inexperienced uninknoewledage people. Combis are brilliant!!!! The only way to go.

 

[oilman]

Combis score in eliminating tanks and cylinders and giving instant DHW for ever.

Some of what you say in your posts is valid for some circumstances, however this sentence might make some think there is more than a coincidence in your username.

 

[Doctor Drivel]

Deleted.

Nothing but abuse.
Not having it
Mod 10

 

[corgiman]

Combis score in eliminating tanks and cylinders and giving instant DHW for ever.

Some of what you say in your posts is valid for some circumstances, however this sentence might make some think there is more than a coincidence in your username.

I recognise drivel when I read it!!! You do come to mind.

Oh good here we go again

Yawwn

 

[Doctor Drivel]

Combis score in eliminating tanks and cylinders and giving instant DHW for ever.

Some of what you say in your posts is valid for some circumstances, however this sentence might make some think there is more than a coincidence in your username.

I recognise drivel when I read it!!! You do come to mind.

Oh good here we go again

Yawwn

Good!! go to sleep, where many "plumbers" have been for decades.

 

[Balenza]

Doctor Drivel wrote

Not so. As combis command the lions share of the market, they are cheaper and more deals are on them

Their only designed to last a few years and then the insides start failing and the manufacturers charge a mint for spare parts which is where they make their money IMHO.
Hell would freeze over before Id swap my cylinder and tank (and simple boiler set up) for a combi. No sirreeeee.

 

[corgiman]

Combis score in eliminating tanks and cylinders and giving instant DHW for ever.

Some of what you say in your posts is valid for some circumstances, however this sentence might make some think there is more than a coincidence in your username.

I recognise drivel when I read it!!! You do come to mind.

Oh good here we go again

Yawwn

Good!! go to sleep, where many "plumbers" have been for decades.

beat you to it Dr Boring, Snooooore

 

[Balenza]

Mikej2005 wrote

We've got an electric shower as a back-up for hot water.

Thats handy. If you wanted to wash the dishes then you could just extend the shower hose with some extension piping to the kitchen sink.

 

[Doctor Drivel]

Doctor Drivel wrote

Not so. As combis command the lions share of the market, they are cheaper and more deals are on them

Their only designed to last a few years

They are not!!

and then the insides start failing and the manufacturers charge a mint for spare parts which is where they make their money IMHO.
Hell would freeze over before Id swap my cylinder and tank (and simple boiler set up) for a combi. No sirreeeee.

The same components are in system boilers. Buy a good quality combi and then no problems.

 

[oilman]

The same components are in system boilers. Buy a good quality combi and then no problems.

But not all of the components used in combies are used in system boilers. Components that are fitted inside the boiler cabinets live at a higher temperature. Consequently they fail sooner than those that live at lower temperatures.

Look at thr forum postings, most boiler problems come from combi boilers.

 

[Doctor Drivel]

The same components are in system boilers. Buy a good quality combi and then no problems.

But not all of the components used in combies are used in system boilers. Components that are fitted inside the boiler cabinets live at a higher temperature. Consequently they fail sooner than those that live at lower temperatures.

Look at thr forum postings, most boiler problems come from combi boilers.

Oh not one of these blind people again!!! millions of them!!! All of the system is inside the casing in a combi. If the 3-way valve goes at a cylinder it is never reported as "boiler" fault. Get real and look.

 

[oilman]

You're quite a defensive type aren't you? I assume you are able to differentiate between a "system" boiler and a "combi" boiler. Let us know if this is ok so far and we'll take the next step. However, if you are going to throw your toys out of the pram, you will have to carry on playing with yourself.

 

[Bahco]

Where should this Ethos combi go in the list?

Is it top rated or other?

 

[Doctor Drivel]

You're quite a defensive type aren't you?

NO. I attack!!!

I assume you are able to differentiate between a "system" boiler and a "combi" boiler.

You are extracting the urine I see. Not very well either.

 

[Doctor Drivel]

Where should this Ethos combi go in the list?

Is it top rated or other?

It is a very well made boiler. Highly specced, high quality, small case size, high DHW output and cheap for what it is. 23 litres/min @ 35C temp rise. In other word it give what a heat bank or unvented cylinder can deliver and at higher pressures.