For this case study, we find ourselves in Oxted, Surrey.  We like Oxted, because it is a lovely, virtually unspoilt town (if you exclude Morrisons) full of coffee shops and yummy mummies.  I suppose it is similar to Sevenoaks with all the good bits squeezed into a smaller area.  It is also very close to Hot Water & Central Heating Ltd HQ, so we get a lot of projects there.

Let the boiler renewal commence…

A larger house, this had a Keston C55 boiler and a significant number of radiators.  The Keston boiler had been unreliable (no surprises there) so we suggested a Worcester-Bosch alternative.    Interestingly, the Keston and all the radiators had been specified 10 years ago by a local heating firm specialising in AGA cookers, who, having installed the Keston boiler, refused to service it thereafter because they said they didn’t know how it worked.    I can’t see us getting away with those type of excuses!

If a customer has had an unreliable boiler, a Worcester sells itself because by definition it will be a revelation.  Generally, the only pundits who say in their experience a newer Worcester has not been reliable are those who have, either wittingly or unwittingly, not had the thing installed correctly.  System (radiator) cleansing is one of the most important parts of a boiler renewal, far too many people get a cheap ‘quick and dirty’ job done.  The repercussions normally take around 18 months before sludge migrates into the new boiler, whereupon it will never be the same again.

Anyway, back to the case study.  Our customers are a semi retired couple who were recommended our services by their daughter, who was in turn recommended by a family friend.  So this is the third boiler renewal from one particular job.

The house is probably larger than two people need, but it is home, and their family often come to stay.  Therefore it seemed ideal for a zoning system, the owner knew this, and was very keen on the Honeywell Evohome.   He knew he could use it to direct heat to different parts of the house depending on who was in residence!

Invasion of the evohome radiator zone valves

The Keston flue system used up a significant part of the roof, so we asked our roofing specialist contractor (Dave) to fit the new Worcester-Bosch  flue terminal and cover the old zinc plate aperture with spare tiles.

Keston flue system



Dave, our roofer, professionally reorganises the tiles

New Worcester flue.

The boiler system was changed over for a new Worcester Bosch 40CDi Regular, and a Worcester System filter was used to obtain an 8yr parts & labour warranty.

Boiler repair men like these. Pays for their holidays.

New boiler system, based around a Worcester Bosch 40CDi

A new Grundfos Magna2 varispeed low energy light commercial circulation pump was fitted, which is perfect with the new Honeywell Evohome, where typically only a few radiators might be connected at a point in time.

The Evohome system used around 40 radiator heads and allowed 12 separate zones to be created, plus hot water control.  We also added a 13th separate frost protection zone for an external store area.

Although the Bosch boiler is around the same efficiency as the Keston, significant gas savings can be expected because of the zoning.  The electrical consumption of the boiler and pump will be significantly reduced too.