For this case study, we are in Ealing, West London.
Here we are in North West London
Our customer rang us to say he had inadvertently bought a large house with a woefully complex heating system around 8 years ago. The first time he viewed the house, it was perfect – but they never went into the garage. On the second visit, he popped his head into the garage area, and found it completely full of commercial plant, and a ambient temperature of over 30C.
Our customer and a small part of his plant room
Since then, many a central heating specialist has escaped having seen the garage; apparently they are brimming with confidence until the door opens and they run for the hills, never to return.
A bit more of the plant room, water boosting to the right
This was a fascinating story, so against my wife’s advice I just had to have a look. She says I always take on the difficult heating renewal jobs, and why can’t we do more normal work?
The answer is, of course, that all plumbers go for the easy work, but in the mass market some won’t powerflush or design the system properly, and undercut the professional installers who have priced o do the job properly. I can’t change that, although I am fed up with all the calls we get asking us to look at ropey budget installs and fix them up. (Just for the record, we don’t get involved if another installer has already done the bulk of the work).
So, here we are, the garage is absolutely stifling hot and the plant room is scoped big enough to heat most of the road, as well as the house. The control system is in a commercial panel 2 metres square with a 60A per phase three phase isolator, and is full of Staefa relays and cabling.
Remember, this is a domestic property!
There are a couple of process controllers (a form of building management system) loose in the bottom and further controllers throughout the house, including temperature controllers and programmers in each room. The whole system is 16 years old and has been obsolete for years, so the only way it can be made to work is to be on all the time, all year round.
State of the art in 1998
The boiler plant was fed from two 46Kw Broag Quinta condensing boilers, one of which has been changed a few years ago and the flue system crudely adapted to suit. No screws, pipes about to drop off, not good. There was a locally fabricated low loss header, literally miles of control cabling in metal trunking, and two large hot water cylinders, a commercial pump set with three sequencing pump heads, 2000 litre breaktank etc etc.
We left the water break tank pump system in place for the time being, these could be replaced by accumulators in future
After having a good look at the system, we recommended leaving most of the pipework and radiators, as well as the underfloor heating, simply changing the boilers and cylinders, and upgrading the control system.
For the boilers, we calculated the 92Kw boiler plant was a fair bit oversized, so we specified a Worcester Bosch GB162 rated at 65Kw. Both the boilers were scrapped, together with the flue system, which was leaking from various joints as it proceeded sideways and upwards to a roof terminal three floors up. The flue system was replaced with a modern stainless steel type, which involved a large amount of scaffolding at the rear of the house due to difficult access.
Getting access to replace the flue was difficult due to the overhanging eaves of the adjacent property. Our clever scaffolders came up with a solution
We changed both the unvented cylinders for new Santon 300Litre unvented units, which unlike the originals, have superb heat insulation.
New Worcester Bosch commercial GB162 boiler and our controls starting to be installed. The new timers are for secondary pumps for hot water circulation
The low loss header was retained and used to act as a buffer between the single GB162 boiler and the heating zones, maintaining the correct flow of water through the boiler heat exchanger.
Starting to strip down old control panel
Now to start on the mains side of the panel…..
8 hours later, nothing remains. I took out the old telephone PBX too (on the request of the customer)
We used Honeywell Evohome to replace the entire control system, so now a simple touch panel is all that is required to control 12 zones of heating and one of the hot water cylinders. A second Evohome will be added in late 2014 to give up to 24 zones of heating control, linking the previously defunct underfloor heating system into the new plant, and allow control of the second hot water cylinder. All this can also be controlled via iPhone, iPad app – or if you must, an Android device.
The first of two Honeywell Evohomes for this house
Our customer was relieved, because he was anticipating having to lift the solid floors in the entire house and replace everything; as things turned out, we haven’t created much chaos at all, apart from in the garage, where things are now much cooler, efficient and simple to maintain.
Final commissioning
Hot Water & Central Heating Ltd did the design, and installation, from start to finish, the work on site took just over 14 days.
