Leaking tap:
Older style taps are fitted with a gland nut
holding in watertight packing around the
spindle. These taps may leak between the
spindle and the cover if the gland nut has
become loose. To cure a similar problem on
modern taps, or to cure a tap which drips,
refer to washer replacement
Tightening the tap gland nut:
Undo the small screw holding the cross
head in place (this may be hiding under a
plastic cover in the top of the tap) and
remove it.
Undo the top cover of the tap by unscrewing.
This may be a metal type with a hexagonal
base, in which case you should wrap some
cloth around it before undoing with a
spanner. The cloth will prevent it being
scratched. Take care to prevent the tap
itself from turning whilst doing this.
With the cover removed, tighten the gland
nut at the base of the spindle with a
spanner.
Hold the tap (wrapped in a rag) with a pipe
wrench to prevent it turning.
Before reassembling, check that the nut is
not so tight as to make it difficult to turn
on the tap. This can be done by replacing
the cross head temporarily without the
fixing screw and testing the tap.
Repacking the tap gland:
If this fails to cure the problem, turn off
the water, remove the gland nut and repack
the gland. Remove the old packing with a
small screwdriver. Replace it with specially
produced packing or, if you are unable to
get hold of this, use string coated with
petroleum jelly. Reassemble and test the
function of the tap.
Tap washer replacement 1:
Locating the washer
Close off the water supply to the tap and open the tap to drain
excess water.
Put the plug in the waste outlet - not to stop loss of water, but to
safeguard against losing any of the tap components when dismantling
it.
Remove the top cover of the tap. This may be a metal type with a
hexagonal base, in which case you should wrap some cloth around it
before undoing with a spanner. The cloth will prevent it being
scratched. Hold the tap itself to prevent it turning.
Some taps have a moulded plastic cover held in place with a small
screw located in its top (sometimes under a plastic insert, which
will need to be gently prised out with a thin bladed screwdriver).
Undoing the tap
Once the cover is removed, undo the top section of the tap by
turning the hexagonal nut next to the base with a spanner.
Hold the tap itself (wrapped in a rag) using a pipe wrench to
prevent it turning.
Lift the top section out of the tap.
Replacing the washer
On the underside of this will be the washer retained by a small nut,
which should be undone, or a button.
Remove the old washer and replace with a new one. Make sure that
pieces of the old washer are not left in the seat of the tap before
finally reassembling it and switching the water back on.
Tap washer replacement 2:
Reverse pressure tap
This is a rather old form of tap but it is quite possible to change
its washer if needs be using readily available replacements.
A valve inside the tap enables the washer may be replaced without
the need to switch off the water supply.
Wrap a cloth around the hexagonal nut above the nozzle and hold it
with a spanner. Unscrew the nozzle with the other hand.
Tap (no pun intended) the nozzle on a block of wood to free the
finned section inside. Remove and replace the combined washer
jumper.
Reassemble the tap and test.
Mixer tap spout
If leakage occurs from the base of the spout, the likely cause is a
worn seal.
Turn off both taps but not the main supply to them.
Unscrew or lift up the retaining shroud.
Lift the spout up carefully.
On some models, the spout is held in place with a retaining screw,
which should be undone.
Remove and replace the worn seal, which is usually an "O" ring type
– like a little rubber ring sitting in the groove on the assembly.
Be sure not to damage or stretch the "O" ring when refitting your
spout. A little silicone lubricant may be used to ease reassembly.
Tap washer replacement 3:
Mixer tap valves
Modern mixer tap valves now have "O" rings in place of the old gland
packing.
To replace these, turn off the water supply to both hot and cold,
remove the cover piece and the circlip holding the stem in place. To
do this, place the blade of a screwdriver between the ends of the
clip and twist – be prepared to catch the clip. Once released, it
has an extraordinary ability to vanish!
Undo the mechanism and remove the assembly.
Remove and replace the "O" rings. Take care not to damage them. A
little silicone lubricant may be used to ease reassembly.
Balancing a central heating
system:
To ensure an even distribution
of the hot water to the radiators in a system you’ll need to do
what’s known as balancing the system. Because the water is pumped
via a pipe, and branches to feed each radiator, the ones at the
beginning of the ‘run’ tend to get more than their fair share.
The way to do this is by using the lockshield valve on each to
regulate the flow of water to the radiator. By partial closing of
these valves the radiators nearest the pump can be restricted more
than those further away.
The best way to get this right is by using radiator thermometers,
which can simply be clipped to the flow and return pipe at either
end, and measuring the difference. You won't often see a plumber
using these though - experience enables them to adjust the valves
without measuring the temperature.
Remember, the pipe to each radiator is a branch from the main flow
pipe. Near the furthest radiator, the main flow pipe turns back
towards the boiler and becomes the return pipe. The pipe from each
radiator then feeds back into this.
The water does not go into the first radiator then out and on to the
next etc. It actually flows from one main pipe feeding all of them,
and then flows back out into the return coming back from all of
them.
Turn the heating off well in advance of wishing to balance the
system, so that the water has a chance to cool right down. Each
radiator has a control valve – the one you use to turn it on or off,
and a lockshield valve – the one with a cover which you don’t
normally turn. To open or close this lockshield valve, you need to
remove the cover and use a pair of pliers. Open both valves on all
the radiators.
Now, turn the heating back on and go to the first radiator. You are
going to adjust them in the order in which they are served, so if
you don’t know this, make a note of the order in which they heat up.
Fit the radiator thermometers to the flow and return. Turn off the
lockshield valve then open it gradually again until the difference
between the two thermometers is about 20 degrees Farenheight.
Move on to the second radiator on the system and do the same. If you
repeat this for all of them in order, you should have a perfectly
balanced system so that all radiators heat up efficiently. You may
find the last one will need the lockshield valve fully open.
Bleeding a radiator:
For sealed systems, seek the
services of a professional heating engineer
Cold radiator
If the top section of a radiator is cold when the heating is on, it
is usually an indication that air has got into the system somewhere
and has become trapped. Air in a radiator will rise to the top
forming a pocket stopping the hot water from getting to that
part.This can be released by bleeding the radiator,, but remember to
turn the heating off first.
When air is bled or released from an open vented system, the water
in the system will be topped up by the feed and expansion tank.
If a radiator in a sealed system needs bleeding the pressure in the
system will be reduced. The system will, therefore, needed to be
toped up. However, sealed systems are different from open vented
ones and have no feed and expansion tank. The instruction manual for
your system may have details of how to top up the system. If not, or
if you have any doubts at all, contact a suitably qualified heating
engineer.
Bleed the radiator
You will need a radiator key and an old rag. Radiator keys are
readily available from DIY stores and ironmongers. Armed with the
rag beneath, use the radiator key to slacken the air bleed valve
which is at one end towards the top of the radiator.
There will be a hissing sound as the air comes out. As soon as water
begins to flow, close the vent again and wipe away any water.
Take care not to get scalded – the water may be pretty hot.
The heating can then be switched back on.
Air release valve
Some systems have an automatic air release valve fitted. This
usually has a small red top which should be slack to enable the air
to escape.
Radiators should not need frequent ‘bleeding’. If they do, air is
getting in and this should be sorted out by a professional heating
engineer.
Corrosion prevention in heating systems:
A few simple precautions can
avoid your system having problems like sludge build up and pinhole
leaks.
Cause of corrosion:
Air getting into the system actually speeds up deterioration as
oxygen is one of the essential requirements for corrosion.
You’ll know if air is getting in because the radiators will need
bleeding to remove the air on a frequent basis.
Where the air gets in though is another matter. It can enter through
a number of routes, but the most common are through the feed and
expansion cistern in the loft, the vent pipe which hangs over it or
a leaking joint beside the pump.
Unfortunately, whilst it is possible to identify these, it is
usually a job for a professional heating engineer to put it right.
Testing for corrosion:
It’s a good idea to add a corrosion inhibitor to reduce the gradual
deterioration of the system. Test a sample of water from your system
each year to see how corrosive it is. Place the sample in an old jam
jar and put a shiny steel nail in it.
Remember not to use a galvanised nail or the test won’t work.
Put the lid back on and leave the jar for a week or so. If the water
has turned orange and the nail is rusty, the water has too much
oxygen and will be corroding the inside of your system in the same
way. You’ll therefore need to put an additive into the system to
reduce this.
Adding corrosion inhibitor:
Read the manufacturer’s instructions carefully
and add the appropriate amount of the anti corrosion liquid. With an
open vent system, this is done by adding to the feed and expansion
cistern.
For a sealed system, you can buy a cartridge of inhibitor which can
be injected in via the air bleed valve on a radiator -
again, you should carefully follow the manufacturer's instructions
for this.
Leaks in central heating
systems:
For sealed systems, seek the services of a professional
heating engineer
Joints in pipework:
Soldered joints which have sprung a leak will need to be
replaced. Drain the system and replace the joint by following the
section on soldered joints.
Compression joint leaks can sometimes be cured by a slight
tightening of the nut.
Remember to hold the other nut with a spanner or wrench to prevent
pulling the joint from the pipe.
Tighten the leaking side a small amount and no more than a quarter
turn. More than this and you’ll damage the joint. If this is not
successful, you’ll need to drain down the system and refit the
joint. Refer to compression fittings in the plumbing section.
Radiator:
Radiators can develop pinholes. This is caused by corrosion due to
sludge or excessive air getting into the system. The air actually
promotes corrosion. The only satisfactory cure is to remove the
radiator and fit a new one. Be sure however to flush the system
through and identify whether air is getting into the system.
Failure to resolve the cause may mean you’ll get very used to
replacing radiators!
Valve connections:
If the valve leaks where it connects to the pipework, you will need
to repair the joint. The system will need to be drained down and the
joint redone. This is a compression type joint and relies upon a
metal collar known as an olive to make the seal when the nut is
tightened. For details on how to make this type of connection see
compression fittings in the plumbing section.
If the leak is the other side of the valve where it goes off to the
radiator, you can turn off both valves and drain just the radiator
in question. Whilst you won’t need to remove the radiator, you’ll
find details on emptying it in the removing a radiator section. Undo
the connection, and wind a length of PTFE tape around the joint
before reassembling and you’ll find that this will help to seal the
thread and stop any leaks. Open the air vent and then open just the
flow valve. Allow the radiator to fill and close the air bleed valve
when water begins to come out. Now open the return valve.
Radiator connector:
Follow the same procedure above to empty the radiator. Disconnect
the radiator from the valve first, then use a large Allen key
inserted in the end to undo the radiator connector. Then clean the
thread and wrap a length of PTFE tape around it. Refit the connector
to the radiator doing it up with the Allen key, and reconnect the
valve.
Air bleed valve:
Partially drain the radiator so that the water level inside is
at least below the level of the air bleed valve. Using an Allen key
inserted into the valve, you can undo and remove it. Clean the
thread and wrap a little PTFE tape around it before reinserting and
tightening it back up. Refill the radiator.
Valve body:
The gland nut at the base of the spindle of a valve sometimes works
loose.
Holding the valve assembly with a pipe wrench to prevent it being
pulled from the pipework, use a spanner to tighten the nut a little.
If this doesn’t do the trick, it indicates that the gland packing
has become worn. Turn off both valves and undo the gland nut. Using
a length of special gland packing, wind a few turns around the base
of the spindle and pack it in tightly using a small screwdriver.
Replace and retighten the gland nut. Open one valve at a time and
check again for leaks.
Problem solving
central heating 1:
For problems relating to
sealed systems, seek the services of a professional heating engineer
Cold top section of
radiator:
This is usually an indication that air has got into the system
somewhere and has become trapped. Air in a radiator will rise to the
top forming a pocket stopping the hot water from getting to that
part. This can be released, but remember to turn the heating off
first. Now, armed with a rag beneath, use a radiator key to slacken
the air bleed valve which is at one end towards the top of the
radiator. There will be a hissing sound as the air comes out. As
soon as water begins to flow, close the vent again and wipe away any
water.
Take care not to get scalded – the water may be pretty hot.
The heating can then be switched back on.
Some systems have an automatic air release valve fitted. This
usually has a small red top which should be slack to enable the air
to escape.
Radiators should not need frequent ‘bleeding’. If they do, air is
getting in and this should be sorted out by a professional heating
installer
Cold bottom section of
radiator:
This is a sign of rust and sludge build up which is sitting in
the bottom of the radiator. Following the guides on removing and
refitting a radiator, take the radiator outside and flush it through
with a hosepipe. If you have the radiator standing on end, you
should be able to flush out most of the sludge.
Remember to carry the radiator upside down so you don't get sludge
dripping on to your carpet.
With an open vent system, you may also consider using a proprietary
heating system sludge remover. This will mean adding it to the feed
and expansion tank and, a few days later, emptying and refilling the
system.
Follow the manufacturer’s instructions.
Upstairs radiators cold:
This is most often an indication that the feed and expansion
cistern in the loft has run dry.
This should not happen and indicates another problem which needs to
be sorted.
It’s probable that the ball valve is not operating correctly. It may
have jammed or be obstructed. Clear any obstruction or replace worn
parts. Remember when refilling and adjusting the ball valve that
there must be enough room for the water to expand when the system
heats up. Therefore, when the system is cold, there should be just
enough water to make the ball to float and switch off the water
coming in.
Downstairs radiators cold:
This is an indication that the pump has packed up. Have it
tested and, if necessary, replaced.
All radiators cold or not
very warm:
This again is an indication of the build up of rust and sludge.
See ‘Cold bottom section’ above.
Radiators cooler in one area of the house
This tells you that the radiators are not properly balanced. The
nearest radiators to the boiler are taking more than their share of
the hot water from the system. See page on balancing the system.
Warm radiators upstairs
when the heating is off, and hot water is on:
If this happens, it is probably because the check valve on a
gravity fed system has failed. In a gravity fed system, the hot
water cylinder is heated by water from the boiler which flows due to
the gravity and not a pump. To prevent the water also heating the
radiators when the heating is off, a check valve is fitted. If this
has failed, the radiators upstairs will begin to receive some of the
heat.
The valve will need to be replaced by a heating engineer.
No heating or hot water:
Make sure that the power supply is on and that a fuse hasn’t
blown. Remember, if a fuse has blown, you should always rectify the
cause first.
As always, take great care with any electrical inspection or work.
See electrics safety
Check that the gas or oil supply has not been turned off
inadvertently.
In the case of oil, check that you actually have some oil in the
tank by reading the gauge.
Check that the programmer is in the on position and that the
thermostats are turned up high enough.
Check that the pump is running.
If not, get a heating engineer in to investigate.
Check that the pilot light is lit.
If it isn't, follow the details for relighting in the boiler manual.
If none of these solve the problem, it’s time to call in a heating
engineer.
Feed and expansion tank
overflowing:
If the ball valve is not closing off the water supply properly,
the cistern will continue to fill and water will come out from the
overflow pipe. The usual cause is either a poorly adjusted valve or
a worn washer. These can both be remedied in a similar fashion to
the ball valve of the cold water storage tank.
Problem solving central heating 2:
Noisy heating:
A number of different things may cause noise problems with a
heating system.
Water gurgling:
This is a sign that air has got into the system. This can be
released by bleeding air from the radiators.
but remember to turn the heating off first
Now, armed with a rag beneath, use a radiator key to slacken the air
bleed valve which is sited at one end towards the top of the
radiator. There will be a hissing sound as the air comes out. As
soon as water begins to flow, close the valve again and wipe away
any water.
Take care not to get scalded – the water may be pretty hot.
The heating can then be switched back on.
Some systems have an automatic air release valve fitted. This
usually has a small red top which should be slack to enable the air
to escape.
Radiators should not need frequent ‘bleeding’.
If they do, air is getting in and this should be sorted out by a
professional heating installer.
Humming:
The pump which sends the water around the system may be set too
fast. In this case , try turning it down to a lower setting. Pumps
can also cause this noise in the pipework through vibration of the
pipes. This can be eliminated by mounting the pump on special
brackets which absorb the vibration rather than transferring it to
the pipes. Finally, the problem can arise where undersized pipes
have been installed.
Check this out with a heating engineer.
Knocks and creaking:
Everywhere that pipes pass through other materials like floor
joists or walls, there is a possibility that they will rub when they
expand or contract unless enough space has been left. If you can
identify where the noise comes from, investigate the pipework in the
area to see where it is rubbing. Rubbing against floor joists where
the notch out is too narrow to allow a little movement, is a common
cause. This can easily be widened by cutting an extra slither away
from one side with a saw and chiselling away the waste.
Take care not to damage the pipe and do not deepen the notch as this
weakens the joist.
You can also pack a bit of fibreglass insulation around them to
cushion the rubbing. This packing can also help where pipes come up
through floorboards.
Sometimes pipes running beneath the floorboards have not been
supported properly. If you find pipework which has a lot of free
movement - for example where they run parallel to the joists - they
will need to be secured. Fit a small batten, screwed between the
joists, and use pipe clips to retain the pipes.
Noisy boiler:
This may be caused by sludge and scale inside the boiler which
results in some areas heating up more than others. The result is
usually intermittent banging caused by pockets of steam. The same
sludge build up can also restrict the flow of water which will
result in noisiness. Air in the boiler may also cause noises.
With any of these, it is recommended that you seek the services of a
professional heating engineer.
There may be a lack of water. Check the feed and expansion tank. If
it is not topping up when the ball valve is opened, there may be a
frozen pipe, air lock, or the mains water may have been switched
off.
