Finding PROPER heating engineers in our area (Hants/Surrey)

[Deleted member 105431]

You forget in the calculation, A combi is 10 x less reliable than a heat only boiler, and any gains plus a lot more besides will be eaten up in repair costs.

Efficient they may be, eco, friendly they certainly aint.

Get coat and exit quick

do u have any info to back this up? what about failure rates on system components such as zone valves, external pumps, expansion vessels,prv's etc?

any cheap boiler be it combi or heat only is generally not cost effective long term (dust to dust)

 

[doitall]

Why would the poster need a WB42CDi for a 3bed house with one bath.

A 150 litre cylinder would be plenty and the boiler half that size.

 

[corgiman]

Why would the poster need a WB42CDi for a 3bed house with one bath.

Might have HUGE rooms and a MASSIVE bath DIA??

Tee hee

 

[doitall]

Why would the poster need a WB42CDi for a 3bed house with one bath.

Might have HUGE rooms and a MASSIVE bath DIA??

Tee hee

Like a hot tub in the garden

 

[doitall]

You forget in the calculation, A combi is 10 x less reliable than a heat only boiler, and any gains plus a lot more besides will be eaten up in repair costs.

Efficient they may be, eco, friendly they certainly aint.

Get coat and exit quick

do u have any info to back this up? what about failure rates on system components such as zone valves, external pumps, expansion vessels,prv's etc?

any cheap boiler be it combi or heat only is generally not cost effective long term (dust to dust)

Let assume the system is installed as it should be.

A honeywell flow share valve is at least tens times more reliable than a combi equivalent. external Grundfos pumps average half the price of a combi or system boiler, same pump different case, Why!!!!!!!. Expansion vessel goes, 15 minute job to change, combi 2 hours plus to take the boiler off the wall strip it down put it all back together replace any parts, check the flues and re-commission. Prv's as above 10 min job easy access, strip half the boiler down just to find it.

As I said before Generic parts, are generally half the price of manufacturer specific. and in most cases twice as reliable.

The more gadgets the bigger the failure rate.

 

[doitall]

Oh, and one more thing, the heating don't go cold every time you run a bath

 

[tonybhoy]

Oh, and one more thing, the heating don't go cold every time you run a bath

Doesn't get cold in Bath does it?

Hot water is priority on any system so a depleted unvented takes about 15minutes to recover fully which is a lot longer than a decent sized combi anyway you hardly notice the drop in temp unless you have teenagers who practically live in the shower

 

[tonybhoy]

Why would the poster need a WB42CDi for a 3bed house with one bath.

A 150 litre cylinder would be plenty and the boiler half that size.

All relative though isn't it. I was simply quoting costs for equipment I've bought recently. Hardly massive savings with a smaller boiler and cylinder though.

 

[doitall]

Have you ever tried to get kids to shut doors and turn off lights

Mine used to open the window so the estate could here the music, then complain it's cold

 

[Agile]

You forget in the calculation, A combi is 10 x less reliable than a heat only boiler, and any gains plus a lot more besides will be eaten up in repair costs.

Efficient they may be, eco, friendly they certainly aint.

I dont know where you dream up your figures!

A Viessmann or a Vaillant have all the same combustion parts in the "heat engine", the same pump, the same or similar control systems.

The only difference is the addition of a DHW flow switch, a diverter valve, a passive secondary heat exchanger and a DHW temperature sensor.

The only additional parts to fail in a combi are those specifically used for DHW production. The diverter valve is removed from the equation because one is still required for a storage system.

A combi uses just 0.14 kWh per day if not used. That costs 2p per day.

A cylinder loses about 2.4 kWh per day. Costing 29p per day!

This complaint of waiting for heat affects both types and is primarily because so few installers lag the HW pipes.

Tony

 

[doitall]

You forget in the calculation, A combi is 10 x less reliable than a heat only boiler, and any gains plus a lot more besides will be eaten up in repair costs.

Efficient they may be, eco, friendly they certainly aint.

I dont know where you dream up your figures!

A Viessmann or a Vaillant have all the same combustion parts in the "heat engine", the same pump, the same or similar control systems.

The only difference is the addition of a DHW flow switch, a diverter valve, a passive secondary heat exchanger and a DHW temperature sensor.

The only additional parts to fail in a combi are those specifically used for DHW production. The diverter valve is removed from the equation because one is still required for a storage system.

A combi uses just 0.14 kWh per day if not used. That costs 2p per day.

A cylinder loses about 2.4 kWh per day. Costing 29p per day!

This complaint of waiting for heat affects both types and is primarily because so few installers lag the HW pipes.

Tony

Facts the Tony, how reliable is a diverter valve in a combi boiler compared to say a Honeywell that has fitted correctly, and howmuch would you charge to change a Viessmann and Vaillant DV.

Why is the average combi pump twice the price of an generic one.

How much to change an expansion vessel or would you just fit a remote one, £100 to cheap ? or is it nearer £150.

Why should a combi not be used and not a cylinder, you either want hot water or you don't.

A heat only boiler doesn't have a pump, its remote, you're thinking of a system boiler.

I'm not an idiot that knows nothing and pretends as well you know.

 

[Agile]

A heat only boiler doesn't have a pump, its remote, you're thinking of a system boiler.

A heat only boiler will still need a pump in the system and since they are mostly made by either Grunfos or Wilo, the pump will have the same reliability if its in the boiler or external.

The same with a diverter valve. An external diverter valve is still needed in a conventional system and judging by the number I have to repair they are equally reliable outside the boiler as inside.

The costs of parts is another matter. However, many boiler pumps can be replaced with generic pump heads ( if you know which to use ).

I would therefore disagree with your statement that a combi is 10 X less reliable than a conventional boiler.

Tony

 

[doitall]

So why is one pump more than twice the price of another almost identical generic pump.

Why did a certain boiler manufacturer change the design of the pump so the generic head wouldn't fit.

How much is an Vaillant combi pcb compared to the same boiler heat only

 

[Agile]

So why is one pump more than twice the price of another almost identical generic pump.

Why did a certain boiler manufacturer change the design of the pump so the generic head wouldn't fit.

How much is an Vaillant combi pcb compared to the same boiler heat only

All because the boiler makers dont make much profit from boiler sales and have to make it from spare parts. No difference from cars!

The more unique a boiler pump the less likely a boiler repairer will not be able to find a suitable generic pump.

Tony

 

[Locoblade]

Back on track slightly, what about the efficiency question I posed yesterday about whether combis running at full chat supplying a bath are running as efficiently as a smaller boiler heating a tank over a longer period beforehand? If I recall correctly, I read on here comments suggesting that many combis don't condense on the water heating circuit, is that true, and if so, I assume that does affect their efficency somewhat?

Tony mentioned that the average cylinder loses 2.4kw per day, but if the boiler ran more efficently and so needed to output 2kw less energy per day to heat that water compared to a combi, then overall the losses are tiny. Im not saying this is true or accurate, but we don't seem to have all the figures to hand to actually qualify whether a combi is significantly more effient or not, its just an assumption based on storing water losing heat is always going to be less efficient.

Tony(bhoy) - regards the relative costs up front, yep I accept that a cylinder system is going to cost more up front so if you factor that in then its going to take a long time to recoup the additional investment even if the more expensive system was more efficient (which its unlikely to be), but as discussed previously there are benefits to having a cylinder so although I may be happy to pay for the benefit up front, I wouldnt necessarily want to do that AND pay for it again and again with significantly higher running costs, IYSWIM.