Plumbing emergencies!

[park381]

Originally Posted by derekgas

Thank you, I will tell the boss, though i'm sure she knows, she is pretty good at what we do!

Have just added to my previous post, do you service a boiler combi or system as per the manufacturers specification and guide lines

[derekgas]

Originally Posted by park381

Not bad, a well designed website, one thing your website does not tell me is that the boiler is serviced to the manufacturers specification. Do you strip and clean the combustion chamber, and clean off the burner ass.?

In respect of servicing, the conventional (non condensing) boilers are stripped and cleaned, condensing boilers are not to be touched inside the heat exchanger for 3 years, the way to check these is by testing the gas pressure (must be 18 millibar) and the flue gas/air ratio must be as per manufacturers instructions. Just as important is the water quality, we test each service to determine water quality, this is because poor system water = short lifespan of the boiler. As explained on the website, many engineers don't have the equipment or capability to service condensing boilers, I was recently told by 3 'engineers' that they service modern boilers, 'the old way', this is impossible.

[park381]

Originally Posted by derekgas

In respect of servicing, the conventional (non condensing) boilers are stripped and cleaned, condensing boilers are not to be touched inside the heat exchanger for 3 years, the way to check these is by testing the gas pressure (must be 18 millibar) and the flue gas/air ratio must be as per manufacturers instructions. Just as important is the water quality, we test each service to determine water quality, this is because poor system water = short lifespan of the boiler. As explained on the website, many engineers don't have the equipment or capability to service condensing boilers, I was recently told by 3 'engineers' that they service modern boilers, 'the old way', this is impossible.

I would assume that a large %age of the boilers you work on are "the conventional type"

[derekgas]

Originally Posted by park381

I would assume that a large %age of the boilers you work on are "the conventional type"

It is fast becoming the other way around, we installed 45 last year, 37 year before and 32 year before, customer base is about 6,500 in total, half of them regular annual service customers, and currently 361 on breakdown cover, 25% on cover are condensing boilers.

[park381]

Originally Posted by derekgas

It is fast becoming the other way around, we installed 45 last year, 37 year before and 32 year before, customer base is about 6,500 in total, half of them regular annual service customers, and currently 361 on breakdown cover, 25% on cover are condensing boilers.

25% sounds about right, what would be a normal charge for your company to

1. Flush out a system
2. Replace a conventional combi (say a potterton puma 80) with a condensing combi boiler of the same rating.
Would the customer be looking at say £1500 -£2000 or more

Are combi boilers the answer, are they energy efficient?

[derekgas]

Originally Posted by park381

25% sounds about right, what would be a normal charge for your company to

1. Flush out a system
2. Replace a conventional combi (say a potterton puma 80) with a condensing combi boiler of the same rating.
Would the customer be looking at say £1500 -£2000 or more

Are combi boilers the answer, are they energy efficient?

Powerflushing is £300, a Worcester Bosch 30si, with 5 years guarantee, a magnaclean unit, powerflush, manual (mechanical timeclock), horizontal flue, and 2 years free servicing is about £2100.

[park381]

Originally Posted by derekgas

Powerflushing is £300, a Worcester Bosch 30si, with 5 years guarantee, a magnaclean unit, powerflush, manual (mechanical timeclock), horizontal flue, and 2 years free servicing is about £2100.

That is a big investment, so the home owner could be looking at £2500 to replace his conventional combi with one that complies with L1 of the building regs.

But what about my question regarding combi boilers, are they energy efficient?

[derekgas]

£2500 is nearer the cost for a 35cdi which condenses in hot water as well as heating mode, or for conversion from regular boiler (with tanks) to a combi, regular combis are around 75% efficient, condensing combis are around 90% efficient, the best I have had is 96% efficiency with it going flat out, an average is more like 90.3, the difference in different machines is negligable with condensing boilers, but quality and reliability is a different matter.

[park381]

Originally Posted by derekgas

£2500 is nearer the cost for a 35cdi which condenses in hot water as well as heating mode, or for conversion from regular boiler (with tanks) to a combi, regular combis are around 75% efficient, condensing combis are around 90% efficient, the best I have had is 96% efficiency with it going flat out, an average is more like 90.3, the difference in different machines is negligable with condensing boilers, but quality and reliability is a different matter.

I will go along with that, but my point was are combi boilers energy efficient, what about the cold water draw off before you get hot water, more so on "longish" pipework runs, is that not a waste of water?

What are your thoughts on the companies that advertise on Ebay and still sell conventional combi boilers that you as a corgi reg contractor could not install because they do not comply.

[derekgas]

Long piperuns should be avoided where possible, most modern combis have a pre-heat system, so if the boiler is installed in the cylinder cupboard, the length of wait should be similar to that with a cylinder, a combi of any description is more efficient than storing water, it is worth noting that with a combi, you need good water pressure (cold), no matter how big the boiler is, it can only provide an equivalent amount of hot water that is available from the cold mains, if pressure is not good enough, then a hot tap opened downstairs will drop the pressure to an outlet being used upstairs at the same time, the only way to guarantee hot water throughout in this case is a 'y' plan system (keep the cylinder), but then the system efficiency is affected.

[park381]

Originally Posted by derekgas

Long piperuns should be avoided where possible,

That may be all well and good in a new build house, but not always possible in an existing house. Most boilers are sited in a kitchen with the bathroom not directly above.
Have seen installations where combi boiler in installed in a garage, and the cylinder (first floor) has been removed, pipework linked so the hot water flow is to the first floor before coming down to the kitchen, that is a lot of water to waste, may be a wrong application/position of the combi boiler.
In most cases where a normal system boiler/cylinder is replaced by a combi boiler that is what happens.

With a combi there is always the drop in temperature of the incoming mains cold water in winter, all combi boiler manufacturers use the 35* temperature rise as a yard stick, so in winter the temperature of the hot water produced is relative to the reduced temperature of the incoming cold water. That is unless the combi boiler is way oversized.

[park381]

Very interesting conversation, Merry Christmas derekgas.

Am going for my Christmas Dinner now

[derekgas]

Originally Posted by park381

That may be all well and good in a new build house, but not always possible in an existing house. Most boilers are sited in a kitchen with the bathroom not directly above.
Have seen installations where combi boiler in installed in a garage, and the cylinder (first floor) has been removed, pipework linked so the hot water flow is to the first floor before coming down to the kitchen, that is a lot of water to waste, may be a wrong application/position of the combi boiler.
In most cases where a normal system boiler/cylinder is replaced by a combi boiler that is what happens.

With a combi there is always the drop in temperature of the incoming mains cold water in winter, all combi boiler manufacturers use the 35* temperature rise as a yard stick, so in winter the temperature of the hot water produced is relative to the reduced temperature of the incoming cold water. That is unless the combi boiler is way oversized.

You are right, I always try and utilise the airing cupboard for that reason, if the garage is used, I would usually try and arrange the pipework to a more suitable position, if a combi is used correctly and correctly sized, the temperature difference should only be relevant to the time taken to run a bath, the temperature control should be set that when a basin or sink tap is opened, the water is the correct temp, then turned up to facillitate the running of the bath, otherwise, the tendency is to run the water too hot, then use cold water to cool down what you just paid to heat up = innefficiency. Also. with Worcester, the stated temperature rises are minimum rises, they are actually better than quoted, ie a 30si usually does 14 litres pm at 35c rise in mild weather.

[derekgas]

Originally Posted by park381

Very interesting conversation, Merry Christmas derekgas.

Am going for my Christmas Dinner now

Merry christmas park381.