if you adamant about using a combi that will fit in the cupboard then perhaps the remeha broag 35c or 39c would be a better choice.
I have fitted a few flexicoms and also the broags. The broags are a much better boiler with internals nearly as good as vaillants.
Price wise they are only slightly more than a flexicom.
The 39c would be able to manage about 50% more than your current boiler.
Otherwise my reccomendation would be to have an unvented cylinder fitted in the house if you had space.
The Broag is a great boiler and buy the outside weather temperature sensor.
Unvented cylinders? Not a good idea as they need a £100 a year service charge ..... they blow up too:
Water heater blasts:
http://au.youtube.com/watch?v=pu3FwgIHsQA
http://au.youtube.com/watch?v=GF_Wrm-Ns0I
http://www.masterplumbers.com/plumbnews/2001/dec/avon.asp
http://seattlepi.nwsource.com/local/33094_boom28.shtml
http://www2.canada.com/edmonton/edm....html?id=02acabcc-e7c4-43e4-8fe0-5c298527e2d5
http://www.abc15.com/news/local/sto...orth-Phoenix-home/7p8jpeMzcU664FSrKb_osA.cspx
An exploding water heater ripped apart a north Phoenix home Thursday morning.
Video from Air15, near 40th Street and Thunderbird Road, showed a hole in the roof of the garage, a pile of rubble, and debris blown out into the neighborhood.
Watch the RAW VIDEO of the explosion scene
The water heater ended up on a sidewalk about two blocks away, across from a school.
Fire spokesman Victor Rangel said the temperature and pressure valve malfunctioned, sending the water heater skyrocketing.
Nearby residents were evacuated as a Southwest Gas crew and agents from Alcohol, Tobacco and Firearms investigated. Neighbors were allowed back into their homes after about two hours.
Many neighbors described the sound of a bomb, with windows shattering, walls shaking, and in one home pictures falling off walls.
A neighbor's wall was damaged by the explosion, which also broke windows in a house across the street.
One woman who lives two blocks away said the blast knocked all the pictures off her walls.
Click related link to right to see a water heater explosion.
Most of the damage occured to the house next door and directly across the street. However debris from the blast could be seen in yards and on roof tops.
According to Phoenix firefighters, the owner of the house was asleep when the blast ripped apart his garage about 5 a.m.
Red Cross relocated the homeowner.
No one was injured.
Rangel said he's never seen this happen and he'd spoken to several plumbers who had heard of hot water heaters exploding, but had never seen it happen.
He said homeowners need to keep up with the maintenance of water heaters; sometimes the T and P valves become corroded or have been installed improperly.
Rangel suggests having the units checked by a professional, especially for people buying homes that have gone through foreclosure. A home bought after a foreclosure might not have gone through an inspection, especially in a short sale.
Water heater warnings and tips from the Phoenix Fire Department Most of the time, your water heater just sits where it’s been placed, quietly doing its job. But unlike your family pet, if it’s unhappy it’s not going to walk to the door and bark and scratch. It could just suddenly blow up like the one that exploded this morning near Thunderbird Road and 38th Street.
What? You didn’t know that your water heater could be so lethal? It can be if a tank has been improperly installed, if hazards have been allowed to develop over time, if it has been improperly vented, or if the pressure relief valve has been tampered with.
Here are some safety tips to use when operating your hot water heater:
TEMPERATURE/PRESSURE RELIEF VALVE (T&P)
This valve is designed to prevent a tank from exploding if temperature or pressure exceeds safe limits, by opening and venting. Unfortunately, residential valves are somewhat prone to failure. They should be checked once a year by pulling up on the handle. Water should flow freely out and stop when you let go of the handle. If it does nothing, runs or drips, then the valve should be replaced. Hooking up the drain line with a union or flex connector makes T&P replacement MUCH easier.
People don't like to test their T&Ps. But when water heaters explode, it's catastrophic. People are injured or die; buildings are severely damaged. Test your T&Ps!
Also, T&P drain lines should go down and out. Never up. If the valve opens, water will pool there and corrode it shut.
Finally, if water is running out of your T&P line, look for the cause. It might just be a bad T&P. But it could also signal high-pressure problems or a dangerously defective control. Don't ignore it!
