General Information and Downloads

Why won't my combination boiler supply hot water to more than one tap at a time?

This is because all combination boilers have to warm the water up from cold as it is running and this takes a lot of energy, this is limited to gas supply so all manufactures limit the boilers to about 30KW(input & 28 output) and this is just enough to lift the water temperature up to 60deg C if water flow is slowed down to about 1.5 Gall/min. most combination boilers can only raise the cold water temperature by 35C unless you slow the tap down. a 24KW boiler will not be as good, this is why combination boilers are only recommended for smaller homes with a low hot water usage and defiantly not for homes with more than one bathroom.

Are Combi's only used on sealed systems?

Combination boilers are designed to be used on sealed systems that is they have an expansion vessel built in. but if fitting one onto a system with old radiators then it is sometimes advisable to fit an expansion tank so the extra pressure can not damage the radiators or valves

Why do my radiators keep bursting?

The most common reason is corrosion in the system, this can be caused my the system not being flushed out correctly when new or being wrongly installed, but it takes quite a few years for the first radiator to leak. the system needs checking over, if any design fault is found it needs rectifying then flushing out and inhibitor added

One off My Radiators is cold ?

When you bleed the radiator did water come out?

If not & if you have a sealed system is the pressure gauge at 1 Bar?

Try turning the Radiator valve fully open (anticlockwise ) & on the opposite side there should be a cap that you can't turn, remove this cap & using a small spanner make sure that the valve spindle is fully open (anticlockwise )

If still no heat try turning all the remaining radiators off and then put the heating on only

How do I top up a sealed system boiler ?

The boiler pressure should be at 1 bar, which will need topping up manually by the fill loop

This is usually under the boiler and may have one or two taps on it and should be a flexible pipe

Fill to one bar, Bleed all the radiators and Refill to one Bar

What is the difference between a plumber and a heating engineer?

Plum is a term for lead so plumbers originally worked with lead putty & paint, so you would call a plumber to fit windows or the lead piping for the water, but over the years plumbers have concentrated on the plumbing of water and the drains and they take plumbing qualifications

Heating engineers have always concentrated on heating systems both design and maintenance,

Lead can no longer be used so both plumbers and heating engineers use copper & plastic and because both types of installation work are now very similar the public think plumbers are Gas Experts especially since the demise as what was known as The gas board

since the invention of the combination boiler which needs virtually no design as everything is built in then a lot of plumbers are now installing boilers (mostly Combination boilers) but unfortunately quite a few still only have there plumbing qualifications plus a basic Gas Safe registration which is why a lot of plumbers will install a boiler but not maintain it and is also why they tend to recommend Combination boilers

A Gas heating engineer should be able to install any type of system and solve any problem on a Ch system but will not fit bathroom suites or work on drains

so there are 2 distinct trades that have merged together over the years and there are good & bad plumbers as there are good and bad heating engineers

What is a power shower?

A power shower can only be used on a normal vented hot water cylinder as these are Powered by an electric pump to increase the water flow to the shower head, so these must not be used with a combination boiler or unvented cylinder as these are more powerful anyway because of the mains water pressure, if you can get the header tank 2m above the shower head then will create enough water pressure for a good mixer shower without buying a power shower

Have I got sludge in my system?

Sludge is only formed if there is a problem with the system

If you get a magnet and touch it to the copper pipes there should not be any attraction, if you find that the magnet is attracted to the copper pipes then you have magnetite in the system, the most likely place is the point that the cold feed enters the system

If you do have sludge then this is usually caused by either the system was never flushed out correctly or it has been piped up incorrectly as on most fully pumped systems the cold feed should enter the system next to the and as close as possible to the Expansion pipe

the magnetite is actually rust from the radiators that are rotting from the inside and will eventually leak if the problem is ignored

also if you have this problem then the radiators need venting regularly

My boiler keeps getting up to 3 Bar and letting water out why?

The pressure should only be at 1 Bar as the safety valve will open at 3 bar for safety as that is its job.

If the pressure gauge is at 1 bar when the system is cold then it rises to 3 Bar when it is hot then it is almost certainly the expansion vessel that needs re-charging with air as it should take up the expanded water when heated.

The expansion vessel is at the back on most boilers but they are usually Red in color so are easy to find.

With the system off & empty of water locate the Shredder valve on the expansion vessel, remove the dust cap and using a Foot Pump put the air pressure up to 10PSI ( you may need to let some more water out of the safety valve by twisting it) replace the dust cap, shut the safety valve and refill the system to 1 bar.

If it still is getting up to 3 bar then either it is getting water from the fill loop of the water to water heat exchanger or the pipe to the expansion vessel is blocked.

I have been recommended an unvented cylinder, what is it?

An unvented cylinder is like a normal indirect cylinder but it works on mains water pressure so will provide hot water at the same flow rate as your cold, all the manufactures are producing these now and most of the better builders are installing these systems in there new housing, they are quite big but you do not need a header tank, they are brilliant for modern mixer & Body showers.