Louise France - domestic heating, plumbing and gas engineer
The engine room in the basement of a house in Wilberforce Road.

Oso 300 litre mains pressure twin coil cylinder. The client wanted to future proof the installation, so a solar cylinder was installed. Both coils have been connected to the central heating, until the panels are fitted. Isolation valves were installed to make the swap simple without the need for a drain down.
The red cylinder is an expansion vessel for the central heating, the white one for the hot water.

Vaillant ecoTEC plus 428 installed on the system above. It has a magnetic filter on the return pipe (above boiler) and a condense pump beneath it, to allow for the condense to be pumped vertically. Although this is an open vent boiler it has been turned into a sealed system to improve performance. The 18 litre red expansion vessel in above picture accommodates the expansion of the water in the system.

This Gledhill high efficiency cylinder is Part L1 compliant. The red expansion vessel has an 18 litre capacity to accommodate the volume of water in the column radiators in this large house. A Magnaclean Twintech is fitted on the return pipe. A Grundfos Alpha 2 circulating pump and Honeywell motorised valves in a S plan configuration. This is hooked up to a Vaillant ecoTEC plus 438 open vent.

Vaillant mains pressure system -
ecoTEC plus system boiler, 155 litre uniSTOR unvented cylinder, Fernox TF1 filter, Honeywell 7 day twin channel programmer and the brilliant CM907 programmable room stat which in particular seems to make a significant improvement on peoples comfort levels and fuel efficiency.
Beneath the sink is a water softener. These require regular topping up with rock salt to maintain the 'softness'. Interesting developments with alternative ways of getting soft water in London, coming soon...

Vaillant's super-compact open vent boiler, the ecoTEC plus 438 packs a punch. This has been turned into a sealed system.

Being open vent, the ecoTEC plus 438 has no internal expansion vessel or pump. These are fitted externally. The large red vessel absorbs the expansion of the water in this sealed system in a large house in Canonbury. Along with a 28mm Grundfos Alpha 2 pump this house was nice and snug last winter (2012).

The challenge here was that no access was available to upgrade the gas supply to this 2 bed flat. The client required a fairly decent shower so only the most powerful of combination boilers would have delivered.
This Vaillant ecoTEC plus 618 and uniSTOR 155 provided the solution: 20 litres of hot water a minute at 60˚C. This is easily enough to deal with the one bathroom at this 2 bed flat in Homerton.

Measuring the gas working pressure on at Vaillant ecoTEC plus 438 open vent. This is an important part of the commissioning process. In this case, the gas supply needed to be upgraded to meet the demand of this boiler.

Commissioning a Vaillant ecoTEC plus 831. The instrument on the side is a combustion analyser and the wireless printer is above it.

Magnetite (sludge) collected on my magnet during a powerflush.
Using this and agitating the radiators is by far the most effective way of clearing a system of the debris that gets built up over time.

'dry' pressure testing a new installation.
I now have a mini compressor!

Careful balancing of the radiators is required to deliver a more even heat throughout the system and keep the return temperature as close to 57˚C as possible. This is the 'dew' point of water which produces the distinctive steam or pluming effect associated with condensing boilers.

Another Vaillant open vent this time with a 210 litre uniSTOR. Unlike a Megaflo this has an external expansion vessel (white). This system is zoned and each floor of this large house has it's own programmable room stat

vintage reclaimed cast iron radiator with brushed nickel valves. Lovely.