boiler is heating radiators but not water

okden

hi and help, i dont know anything about plumbing, but this is the problem as best i can describe

gas boiler is heating radiators but not heating the water in the immersion
electric switch for sink/bath immersion is heating the water (although not a bath amount of water, so the bath element could be broken)
the immersion has a radiator beside it that is piping hot
the immersion has 4 pipes conected to it 2 at the back, 2 at the front, (all cold to the touch)
the lower pipe at the front has a valve on it (half open) which then leads to a T bend up and down
the pipe above the T bend has a valve on it (half open)
the pipe bellow the T bend is as cold as the others but, and this is the strange thing, this pipe is warm/hot just bellow the level of the bottom of the immersion tank.

the valves in the attic from the water tanks are open

the boiler flame is alight all the time hardly ever flicks off unlike the flames ive read about here (although it is turned up high)

the heating sytem can gurgle quitely the odd time if a few unneeded radiators are turned off, and also gives out a big gurgle when the boiler is switched off at night.

ive messed around with the valves a bit but the water is still ice cold, anyone any ideas?

Corkey123

Okden

Is your system capable of heating hot water only. How hold is the system and do you have a control to heatwater only?

Normally on the more modern systems there a valve electrically controled which switches from central heating to heating water. Can you locate such a valve ?

okden

hi martin, its pretty old system, has the 2 tanks in the attic, almost certain its an indirect cylinder like the one on the right in this http://www.diydoctor.org.uk/projects/domestic_hot_water_systems.htm
i had the immersion off and the boiler on last night and the pipes numbered 3 and 5 were cold but just under the level of the bottom of the cylinder the pipe numbered 3 was warm, 6 inches higher it was cold. and the radiator beside the cylinder was piping hot.

karltimber

okden

I have the same system as yourself. your gas boiler will have a hot water out pip - standard stuff - this will then split into two - 1 for rads and 1 for the coil of your Immersion tank. The same goes for the return - 1 from the rads and 1 from the coil in the Im tank.

Check the return pipe from the tank for a valve as it seems the water is heating gradually to the tank but not circulating thru it.

hope this helps

Corkey123

Okden

You should have two sets of feed and return pipe from the boiler.

One set to feed the rads and return from the rads to the boiler.

The second set to feed and return from the hotwater tank.

When you have your central heating on it should heat the rads and warm the tank.

To heat water only there should a valve which opens the feed and return to the tank and closes it to the rads, this then heats on the feed to and return the tank.

Because you have two sets of feed and return does not mean you can heat water independently of the rads. You require a valve to cut the feed to the rads, this is normally due by an electrical valve. This would be located near the boiler, it should have a manual and automatic setting. If you do have one it could be on the manual setting and set to heat the rads only. However I suspect your system is an old system that doesn't have this facility to heat water independently.

JamesM

Are you sure that you have enough water in the system ? The hot water is often the first thing to be affected when the system is low. Especially if you hear gurgling in the pipes.
Jim.

okden

karl, martin, james, thanks for the replys. i dont think the boiler can heat the water independent of the radiators. its an old piping system and has had bits added over time like a change to gas boiler, new immersion cylinder, new tanks in the attic, gas boiler moved to a new location, all independent jobs.

the last job of moving the boiler was done by cowboy builders so they may have done something wrong. the boiler has 2 pipes

cold_in --> pump --> boiler --> hot_out

(is this pumping in the right direction? they got everything else wrong)
this loop heats the rads and the coil in the cylinder at the same time.

the coil isnt heating

the immersion cylinder was put in by a trainie friend who left the trade so he might have botched that

the lower pipe_3 of the coil has a manual valve on it, then a T junction up and down, there is another manual valve on the upper part of the T (this leads to the feed from the small tank in the attic i think), the lower part of the T is warm bellow tank level.

!
valve_2
!
!
pipe_3 --> valve_1 --> T_junc
!
!
V
(warmish)

im thinking, and this is were i show my lack of knowledge 1) sludge in the coil 2) coil leaking into tank 3) pump pumping wrong way 4) air lock in the coil 5) the valves above are set wrong or 6) all of the above

Hagar

The pump itself might be airlocked or have a small obsruction.
On the front of the pump there is a little silver disc with a slot. Use a coin to open it. Be careful of hot water spurting out. You may get air coming out or a small bit of dirt. Screw the disk back in and observe.

JamesM

okden wrote:

karl, martin, james, thanks for the replys. i dont think the boiler can heat the water independent of the radiators. its an old piping system and has had bits added over time like a change to gas boiler, new immersion cylinder, new tanks in the attic, gas boiler moved to a new location, all independent jobs.

the last job of moving the boiler was done by cowboy builders so they may have done something wrong. the boiler has 2 pipes

cold_in --> pump --> boiler --> hot_out

(is this pumping in the right direction? they got everything else wrong)
this loop heats the rads and the coil in the cylinder at the same time.

the coil isnt heating

the immersion cylinder was put in by a trainie friend who left the trade so he might have botched that

the lower pipe_3 of the coil has a manual valve on it, then a T junction up and down, there is another manual valve on the upper part of the T (this leads to the feed from the small tank in the attic i think), the lower part of the T is warm bellow tank level.

!
valve_2
!
!
pipe_3 --> valve_1 --> T_junc
!
!
V
(warmish)

im thinking, and this is were i show my lack of knowledge 1) sludge in the coil 2) coil leaking into tank 3) pump pumping wrong way 4) air lock in the coil 5) the valves above are set wrong or 6) all of the above

Are valves 1 & 2 open ? I presume that valve 2 is the one from the header tank in the attic. Is there enough water in the header tank in the attic ? Was the header tank replaced ?Could there be a blockage in the pipe from the header tank down to the cylinder.
Jim.

okden

JamesM wrote:

Are valves 1 & 2 open ? I presume that valve 2 is the one from the header tank in the attic. Is there enough water in the header tank in the attic ? Was the header tank replaced ?Could there be a blockage in the pipe from the header tank down to the cylinder.
Jim.

yeah they are both opened and i think v2 goes to the smaller of 2 tanks in the attic (is that called the header) and this header has water.
but it could be blocked how could i check for a blockage?
also is the water in the header ment to heat up, i mean if it is part of the radiator water should it not be lukewarm? plumbing is the only diy stuff ive deliberatly avoided, (id hate to leave a slow leak after me and find it a few years later) so as a result i dont understand how it works, but im learning:)

okden

Hagar wrote:

Be careful of hot water spurting out.

i better try that in the morning when its cooled down.

JamesM

okden wrote:

i better try that in the morning when its cooled down.

I wouldn't think that there is a problem with the pump if all the rads are heating.
That is the header tank that you are describing. Unless the pump is too strong, the water would not be hot - it only tops up the system.
To check a blockage, you can poke a wire coat-hanger into the exit pipe, but it will only go as far as the first bend.
This is where the experience of a plumber comes into play - he will know if the next step is to actually open the pipes, or if it can be something else. Sometimes tapping the pipe all the way from the tank to the cylinder will clear a blockage. BUT, this can also move the dirt down into the rest of the system.
Jim.

okden

yeah i think it needs a plumber alright, but ive learnt a lot here, thanks to everyone, even bleed the pump this morning.
whats the deal with the pump direction could it affect the cylinder coil heating in anyway. id be suprized if the builders put the pump on the right pipe even by accident.

JamesM

okden wrote:

yeah i think it needs a plumber alright, but ive learnt a lot here, thanks to everyone, even bleed the pump this morning.
whats the deal with the pump direction could it affect the cylinder coil heating in anyway. id be suprized if the builders put the pump on the right pipe even by accident.

The hot water flows out the top of the boiler. If the pump is on the top pipe the arrow should point away from the boiler. If the pump is on the bottom, return pipe, to the boiler the arrow should point towards the boiler. The arrow is sometimes hard to see - it should be on the side of the pump. You can still make sure that the pipe out of the header tank is clear, with a bit of wire.
Jim.

Marian Hritov

Hello All,
It seems I am have the same problem as user Okden. However I am sure that my heating system is designed with 2 independent heating circles - one for reds and separate for hot water. I had no problem with this until recently. The problem is that when I use the gas boiler to heat up the radiators onle the gas boiler ignites perfect and heats up rads in no time. However if I want to use the boiler only to heat the water it doesnt ignite at all. I have to use my immersion on el.power only. I am nearly a complete newbie in re. plumbing so I am attaching pix to describe my problem. Any reply will be much appreciated guys.

meercat

the valve with no light is the problem valve
there should be a lever on it which you can slide across and hook into open position
this will heat the coil for hot water
the problem may be either
a stuck valve
a faulty valve
a faulty thermostat(pic 3 on bottom of cylinder)
a faulty clock
if you can manually override the valve,your hot water will heat when your central heating is turned on

by the way this thread is 5 years old
start a new one and you may get more replies;)

Athy10

In Marian's last picture, can anyone advise what is the purpose of the rotary valve at the bottom? What should the setting be.

Thanks in advance.

sullzz

Athy10 wrote: »

In Marian's last picture, can anyone advise what is the purpose of the rotary valve at the bottom? What should the setting be.

Thanks in advance.

This is called the balancing valve , you yourself should never have to touch it , it should be set at the correct setting by the plumber , it's purpose is to regulate the flow of water ( heating) through the cylinder coil , ideally it should be closed fully then open just 1 turn, I know some plumbers who remove the wheel head after fitting the valve to prevent people adjusting it .