Thanks to those who got back to me first time round - I turned on topic
watching but for some reason I didn't get notification of new messages
so I didn't realise anyone had replied. Doh!

Anyway, the original message can be found here if you need a recap
http://groups-beta.google.com/group/...d1e1df22371f8a

When we bought the house a couple of years ago the previous owners
asked us if we would like a lesson on how the heating system worked but
we declined as we didn't realize it was anything special. I wish now
that they had told us what was involved. They did at least leave some
notes tied to various pipes which gave us an idea of what to do.

I know enough to keep the system topped up with water (but thanks for
the reminder because it needs doing - how often should it be checked?).
A note tied to it suggests it should be filled to 1 bar so I fill it to
that (+/- 0.1) when the system is cold. When it is fully hot it goes up
to maybe 1.75 at most and there seems to be an emergency pressure valve
set to 3 bar on top of the red cylinder. I've posted some photos of the
system here

http://www.crazysquirrel.com/images/heating/1.jpg
http://www.crazysquirrel.com/images/heating/2.jpg
http://www.crazysquirrel.com/images/heating/3.jpg
http://www.crazysquirrel.com/images/heating/4.jpg

As you can see the Honeywell timer box has been bodged to the wall
using a standard electrical box. I think it must be held on by a piece
of twisted wire or a zip tie - I have been unable to get it off the
wall despite the fact it wobbles every time you touch it so I don't
think it is a screw holding it on. The wobbliness is why I suspect
there may be a loose connection on the back of it.

In answer to some questions raised above:

The large (1inch?) pipes running to the boiler come in the top and can
get viciously hot when the heating is on so I don't think it is a lack
of water.

There is certainly no header tank - the system is sealed (I believe
unvented is the technical term)

I spoke to a plumber (who never showed up - grrr) on the phone when the
problem first appeared. He mentioned the bubble at the top of the hot
water cylinder and I have read what it says on the side of the cylinder
about establishing the bubble. It sounded sufficiently difficult that I
decided to leave it alone (I will try most DIY jobs but I know when to
leave it to a pro). There isn't a problem with getting hot water out of
the tank so I think the bubble is ok if I understand the system
correctly. The tank does need cleaning though as we sometimes get a
little dirty / muddy water out when we first draw water after heating
but I am happy to leave that for now. I would like more information
about this system - I had a look on-line but couldn't really find much.
I have done work on vented systems but this is a totally different ball
park.

I would be really surprised if low water pressure was totally to blame.
Even when the the control box has both switches (bottom right in photo
1) flicked to off and the lights are off the boiler sometimes comes on.
I am fairly convinced that the cavatating of the pump (and hence the
noise) is then caused because the three way valve is set in the off
position so it is pumping against the valve. When this is happening
(and thankfully it's been fine for the last few days) we don't get any
hot water or heating but the boiler is going 10 to the dozen.

Many thanks

doozer wrote:


As you can see the Honeywell timer box has been bodged to the wall;

There are, I think, screws underneath the Honeywell box. Loosening
these will allow the controller to swivelled forward away from the
backplate; pull the plug first since live terminals will be exposed.
You don't have to remove the screws. They are often lost by those who
do remove them, which may be why it's wobbly.

using a standard electrical box.

Probably only one fixing screw will be holding it.

(I believe unvented is the technical term)

It is. Get the installation & maintenance manual from the
Heatrae-Sadia website.

I do not think that the discharge pipes from the two safety valves
(Expansion relief [downstream of the pressure reducing valve] and the
Temperature & Pressure relief [in the cylinder]) have been done
correctly.

There should be a tundish (it could be behind the cardboard label).
There is a 15mm branch below the cardboard label going to the left; I
suspect this is the boiler safety valve discharge. It should have a
separate pipe.

Either one of the two safety valves on the unvented cylinder should be
able to discharge full-bore without causing a flood. You also need to
see is either of them is dripping or discharging, since this indicates
a fault that needs fixing.

Ok, when it's a little warmer (in case I can't get the thing back
together) I will have a bit of a better go at getting the Honeywell box
off the wall. I noticed the screw on the underside before but was a
little scared to remove it till I knew what it was doing ). As for
there being a screw missing in the backing box I don't think so as that
is firmly attached to the wall. It is just the Honeywell box that
wobbles but I suppose I will find out why soon enough.

Not sure what a tundish is. A quick googling seems to indicate that it
is a see-through overflow check point. If it is then we don't have one
(well I've certainly not seen anything that matches that description and
I have had a good look). If you want more pictures I can get some.

There is a large copper pipe (22mm?) that runs down the outside wall to
ground level which I assume is the safety overflow. As some point in the
distant past it has has water down it but I certainly not in the last
couple of years (I suspect from when the system was being installed).

There are no drips or leaks from any of the valves so I assume
everything is working fine. Once in a while I have to top up the water
(where does the lost water go?) but other than that the plumbing seems
to work. I wouldn't be surprised if it was incorrectly installed though.
The previous owners of this place were cowboy magnets.

Thanks.

Graham

Aidan wrote:
doozer wrote:


As you can see the Honeywell timer box has been bodged to the wall;


There are, I think, screws underneath the Honeywell box. Loosening
these will allow the controller to swivelled forward away from the
backplate; pull the plug first since live terminals will be exposed.
You don't have to remove the screws. They are often lost by those who
do remove them, which may be why it's wobbly.


using a standard electrical box.


Probably only one fixing screw will be holding it.

(I believe unvented is the technical term)

It is. Get the installation & maintenance manual from the
Heatrae-Sadia website.

I do not think that the discharge pipes from the two safety valves
(Expansion relief [downstream of the pressure reducing valve] and the
Temperature & Pressure relief [in the cylinder]) have been done
correctly.

There should be a tundish (it could be behind the cardboard label).
There is a 15mm branch below the cardboard label going to the left; I
suspect this is the boiler safety valve discharge. It should have a
separate pipe.

Either one of the two safety valves on the unvented cylinder should be
able to discharge full-bore without causing a flood. You also need to
see is either of them is dripping or discharging, since this indicates
a fault that needs fixing.

When you undo the screws, the controller hinges around the 2 lugs on
the top and can be removed, leaving the back-plate and connections.

It is just the Honeywell box that wobbles but I suppose I will find
out why soon enough.

That's what I meant. The controller has two screws to allow it to be
fixed to a single flush-mounted backing box. You've got a double
surface mounted box, so only the l.h. one of those two screws is
holding the controller onto the backing box.

Not sure what a tundish is.

A funnel. It directs the discharge pipes from the 2 safety valves into
one outlet. It allows you to see whether either valve is dripping. Also
(this is the important bit) if the external pipe is obstructed (by
physical damage, freezing, vandalism, etc) it allows the safety valves
to discharge if a fault occurs. The discharge will go over the floor,
but if there's no discharge then the cylinder could burst explosively.

There is a large copper pipe (22mm?) that runs down the outside wall
to
ground level which I assume is the safety overflow.

Yes. There should be a separate discharge pipe for the boiler safety
valve, with it's own tundish. You need to ensure that 22mm is adequate
for the unvented hot water storage system's safety valves, when the
tundish has been fitted (see the Installation & maintenance manual).
Make sure the immersion heater has the proper thermostat with a
secondary manual-reset thermostat. Or get someone competent & certified
to do it for you. You need to get those things properly serviced
annually.

Yes I too am a little worried, because the quality of installation doesn't look like it was done by a person with an unvented certificate. I am also conscerned that I can't clearly see the tundish.

The item to the left with a large black knob on is your Multifunction control valve, this has a number of duties, it prevents back flow to the water mains, filters incoming water and sets a maximum pressure. To the right of that a much smaller device usually in blue with a number 8 on the front is your expansion valve. In Europe it is normal to allow for expansion of the water as it heats to simply eject from the expansion valve. In the water conservation conscious UK we allow for expansion with either a bubble top or an expansion vessel, so any water coming out of the expansion valve indicates a fualt. Deepending how and when there are different causes behind that fualt. The output pipe of this valve is called D1 and it should fall towards a visible break in the pipework where you could view the water rushing through (or just dripping) this visible thing is called a tundish. The connection at the top right of your cylinder is called a temperature and pressure relief valve. If the user thermostat and also the overheat thermostat fail your next line of defence is the tpr valve. The discharge pipe d1 from this should also drop to the tundish. It is OK for the two d1's to join before the tundish. the discharge pipe after the tundish d2 has be one pipe size larger than d1, and must drop straight down 300mm before the first bend, then gradually all the way to the exit. The size of d1 and d2 depend on distances and have to be calculated. The position of the tundish should be such that you can tell what is going on, but that you won't get scalded by any discharge, it is acceptable to put them to the side of the cylinder not right in your face, but they shouldn't be hidden behind it. Your tundish could well be behind that tag on the right.

There is a zone valve for the central heating connection to the cylinder, which is correct. This fails shut in the evnt of a power cut which is the right thing.

I won't carry on about the position of the discharge pipe and so on, it gets more involved.

The bubble in this type of cylinder naturally becomes smaller until it is ineffective, but it is very easy to reform. The instructions are on the side of the tank. In a nutshell, shut of the cold water supply, switch off all forms of heating, open the nearest hot tap and hold open manually the tpr valve until all gurgling stops, this could take some time. Then let go the tpr valve, shut the tap and turn on the water supply. The bubble will naturally form.

IF YOU EVER SENSE ANY KIND OF DANGER you must A/ turn off all heating sources, i.e. central heating and or immersion heater/s. B/ Open a hot tap. C/ turn off the cold supply to the cylinder. Everything will settle down after that, get an expert in.

When water is under pressure the boiling point is much higher. If any part of the integrity of that vessel or directly connected controls should fail water under pressure would on changing to atmospheric pressure flash over to steam. There is enough power in that flash over from water to steam to blow your house out of the ground.

This particular cylinder is extremely safe and ruggedly constructed, all the necessary controls are designed into the fitting kit to prevent such an event occuring. But you should know it is not something to take lightly. I would recommend you have it checked by a qualified person.

Hmmm, I'm a little concerned now. I have taken another photograph and
labelled it up with what I think each bit is. Could you take a look at
it and tell me if it's correct? If it's any help this system was
installed about 10 years ago. I think I have found the tundish. As a
previous poster suggested it was hiding behind a piece of card. I am
hanging my head in shame for missing that before ).

If you are on a dial up this is a full size picture of about 650KB

http://www.crazysquirrel.com/images/heating/5.jpg

Is it normal to have what we have which is basically just a cut out bit
of pipe for a tundish? Surely that would cause water to flood out all
over the floor rather than down the emergency vent pipe if there was a
problem. As you can see there is a tiny bit of water staining around the
tundish hole but it is dry now and it looks like it has been dry for a
long time.

so any water coming out of the expansion valve indicates a fualt

There is no water coming out what I have marked as the expansion valve.
As you can see from the picture at some point it looks like water has
come out of the multifunction control valve but it has looked like that
since we got the house so whatever caused that crusty build up happened
at least 18 months ago.

If the user thermostat and also the overheat thermostat fail
your next line of defence is the tpr valve. The discharge pipe d1 from
this should also drop to the tundish.

What I have marked as the D1 (Expansion Vessel) doesn't run to the
tundish but it does go to the outside world.

It is OK for the two d1's to join before the tundish.

I am pretty sure they join after the tundish.

the discharge pipe after the tundish d2 has be one
pipe size larger than d1, and must drop straight down 300mm before the
first bend, then gradually all the way to the exit.

The D2 is certainly at least one size bigger. The drop from the tundish
to the D2 join is about 300mm I would guess. The drop from the top of
the expansion vessel to the D2 is probably 300mm but it is in a smaller
bore pipe (the drop is hidden behind the door frame on the left in the
picture).

but that you won't get scalded by any discharge

Any discharge from the tundish will come straight out at us. Brill.

There is a zone valve for the central heating connection to the
cylinder

I could tell which this part was. But I'm glad we have one )

What would be the effect of having no bubble? I haven't done anything
about the bubble as the hot water system works. Wait, don't tell, me no
bubble could result in a catastrophic failure ). What I wouldn't give
for a nice simple vented system right now.

What I have marked as the immersion heater I only assume is an immersion
heater as we don't have a switch or anything to turn on an electric
immersion heater.

I would recommend you have it checked by a qualified person.

As soon as we have the money I will get a decent plumber in to have a
look at it.

Paul Barker wrote:
Aidan Wrote:

doozer wrote:
-

As you can see the Honeywell timer box has been bodged to the wall;-

There are, I think, screws underneath the Honeywell box. Loosening
these will allow the controller to swivelled forward away from the
backplate; pull the plug first since live terminals will be exposed.
You don't have to remove the screws. They are often lost by those who
do remove them, which may be why it's wobbly.
-
using a standard electrical box.-

Probably only one fixing screw will be holding it.
-
(I believe unvented is the technical term)-

It is. Get the installation & maintenance manual from the
Heatrae-Sadia website.

I do not think that the discharge pipes from the two safety valves
(Expansion relief [downstream of the pressure reducing valve] and the
Temperature & Pressure relief [in the cylinder]) have been done
correctly.

There should be a tundish (it could be behind the cardboard label).
There is a 15mm branch below the cardboard label going to the left; I
suspect this is the boiler safety valve discharge. It should have a
separate pipe.

Either one of the two safety valves on the unvented cylinder should be
able to discharge full-bore without causing a flood. You also need to
see is either of them is dripping or discharging, since this indicates
a fault that needs fixing.



Yes I too am a little worried, because the quality of installation
doesn't look like it was done by a person with an unvented certificate.
I am also conscerned that I can't clearly see the tundish.

The item to the left with a large black knob on is your Multifunction
control valve, this has a number of duties, it prevents back flow to
the water mains, filters incoming water and sets a maximum pressure. To
the right of that a much smaller device usually in blue with a number 8
on the front is your expansion valve. In Europe it is normal to allow
for expansion of the water as it heats to simply eject from the
expansion valve. In the water conservation conscious UK we allow for
expansion with either a bubble top or an expansion vessel, so any water
coming out of the expansion valve indicates a fualt. Deepending how and
when there are different causes behind that fualt. The output pipe of
this valve is called D1 and it should fall towards a visible break in
the pipework where you could view the water rushing through (or just
dripping) this visible thing is called a tundish. The connection at the
top right of your cylinder is called a temperature and pressure relief
valve. If the user thermostat and also the overheat thermostat fail
your next line of defence is the tpr valve. The discharge pipe d1 from
this should also drop to the tundish. It is OK for the two d1's to join
before the tundish. the discharge pipe after the tundish d2 has be one
pipe size larger than d1, and must drop straight down 300mm before the
first bend, then gradually all the way to the exit. The size of d1 and
d2 depend on distances and have to be calculated. The position of the
tundish should be such that you can tell what is going on, but that you
won't get scalded by any discharge, it is acceptable to put them to the
side of the cylinder not right in your face, but they shouldn't be
hidden behind it. Your tundish could well be behind that tag on the
right.

There is a zone valve for the central heating connection to the
cylinder, which is correct. This fails shut in the evnt of a power cut
which is the right thing.

I won't carry on about the position of the discharge pipe and so on, it
gets more involved.

The bubble in this type of cylinder naturally becomes smaller until it
is ineffective, but it is very easy to reform. The instructions are on
the side of the tank. In a nutshell, shut of the cold water supply,
switch off all forms of heating, open the nearest hot tap and hold open
manually the tpr valve until all gurgling stops, this could take some
time. Then let go the tpr valve, shut the tap and turn on the water
supply. The bubble will naturally form.

IF YOU EVER SENSE ANY KIND OF DANGER you must A/ turn off all heating
sources, i.e. central heating and or immersion heater/s. B/ Open a hot
tap. C/ turn off the cold supply to the cylinder. Everything will
settle down after that, get an expert in.

When water is under pressure the boiling point is much higher. If any
part of the integrity of that vessel or directly connected controls
should fail water under pressure would on changing to atmospheric
pressure flash over to steam. There is enough power in that flash over
from water to steam to blow your house out of the ground.

This particular cylinder is extremely safe and ruggedly constructed,
all the necessary controls are designed into the fitting kit to prevent
such an event occuring. But you should know it is not something to take
lightly. I would recommend you have it checked by a qualified person.

I know I am talking to myself but I think I have just figured out what
happens if the HW tank looses it's bubble. Ever since we got the house
the HW tap in the kitchen has dripped when the hot water is turned on
and we get a burst of hot water the first time we turn the tap on. As it
has always been like that I assumed that was how it was supposed to be
but thinking about it it probably means that there is little or no
bubble left to take up the expansion of the HW. Re-reading the
instructions on the side of the HW tank I think I have labelled the
temperature and pressure relief valve wrongly and it should be the valve
directly above the tundish on the side of the HW cylinder.

Many thanks for all your help. It's really appreciated.

Graham

doozer wrote:
Hmmm, I'm a little concerned now. I have taken another photograph and
labelled it up with what I think each bit is. Could you take a look at
it and tell me if it's correct? If it's any help this system was
installed about 10 years ago. I think I have found the tundish. As a
previous poster suggested it was hiding behind a piece of card. I am
hanging my head in shame for missing that before ).

If you are on a dial up this is a full size picture of about 650KB

http://www.crazysquirrel.com/images/heating/5.jpg

Is it normal to have what we have which is basically just a cut out bit
of pipe for a tundish? Surely that would cause water to flood out all
over the floor rather than down the emergency vent pipe if there was a
problem. As you can see there is a tiny bit of water staining around the
tundish hole but it is dry now and it looks like it has been dry for a
long time.

so any water coming out of the expansion valve indicates a fualt

There is no water coming out what I have marked as the expansion valve.
As you can see from the picture at some point it looks like water has
come out of the multifunction control valve but it has looked like that
since we got the house so whatever caused that crusty build up happened
at least 18 months ago.

If the user thermostat and also the overheat thermostat fail
your next line of defence is the tpr valve. The discharge pipe d1 from
this should also drop to the tundish.

What I have marked as the D1 (Expansion Vessel) doesn't run to the
tundish but it does go to the outside world.

It is OK for the two d1's to join before the tundish.

I am pretty sure they join after the tundish.

the discharge pipe after the tundish d2 has be one
pipe size larger than d1, and must drop straight down 300mm before the
first bend, then gradually all the way to the exit.

The D2 is certainly at least one size bigger. The drop from the tundish
to the D2 join is about 300mm I would guess. The drop from the top of
the expansion vessel to the D2 is probably 300mm but it is in a smaller
bore pipe (the drop is hidden behind the door frame on the left in the
picture).

but that you won't get scalded by any discharge

Any discharge from the tundish will come straight out at us. Brill.

There is a zone valve for the central heating connection to the
cylinder

I could tell which this part was. But I'm glad we have one )

What would be the effect of having no bubble? I haven't done anything
about the bubble as the hot water system works. Wait, don't tell, me no
bubble could result in a catastrophic failure ). What I wouldn't give
for a nice simple vented system right now.

What I have marked as the immersion heater I only assume is an immersion
heater as we don't have a switch or anything to turn on an electric
immersion heater.

I would recommend you have it checked by a qualified person.

As soon as we have the money I will get a decent plumber in to have a
look at it.

Paul Barker wrote:

Aidan Wrote:

doozer wrote:
-

As you can see the Honeywell timer box has been bodged to the wall;-

There are, I think, screws underneath the Honeywell box. Loosening
these will allow the controller to swivelled forward away from the
backplate; pull the plug first since live terminals will be exposed.
You don't have to remove the screws. They are often lost by those who
do remove them, which may be why it's wobbly.
-
using a standard electrical box.-

Probably only one fixing screw will be holding it.
-
(I believe unvented is the technical term)-

It is. Get the installation & maintenance manual from the
Heatrae-Sadia website.

I do not think that the discharge pipes from the two safety valves
(Expansion relief [downstream of the pressure reducing valve] and the
Temperature & Pressure relief [in the cylinder]) have been done
correctly.

There should be a tundish (it could be behind the cardboard label).
There is a 15mm branch below the cardboard label going to the left; I
suspect this is the boiler safety valve discharge. It should have a
separate pipe.

Either one of the two safety valves on the unvented cylinder should be
able to discharge full-bore without causing a flood. You also need to
see is either of them is dripping or discharging, since this indicates
a fault that needs fixing.




Yes I too am a little worried, because the quality of installation
doesn't look like it was done by a person with an unvented certificate.
I am also conscerned that I can't clearly see the tundish.

The item to the left with a large black knob on is your Multifunction
control valve, this has a number of duties, it prevents back flow to
the water mains, filters incoming water and sets a maximum pressure. To
the right of that a much smaller device usually in blue with a number 8
on the front is your expansion valve. In Europe it is normal to allow
for expansion of the water as it heats to simply eject from the
expansion valve. In the water conservation conscious UK we allow for
expansion with either a bubble top or an expansion vessel, so any water
coming out of the expansion valve indicates a fualt. Deepending how and
when there are different causes behind that fualt. The output pipe of
this valve is called D1 and it should fall towards a visible break in
the pipework where you could view the water rushing through (or just
dripping) this visible thing is called a tundish. The connection at the
top right of your cylinder is called a temperature and pressure relief
valve. If the user thermostat and also the overheat thermostat fail
your next line of defence is the tpr valve. The discharge pipe d1 from
this should also drop to the tundish. It is OK for the two d1's to join
before the tundish. the discharge pipe after the tundish d2 has be one
pipe size larger than d1, and must drop straight down 300mm before the
first bend, then gradually all the way to the exit. The size of d1 and
d2 depend on distances and have to be calculated. The position of the
tundish should be such that you can tell what is going on, but that you
won't get scalded by any discharge, it is acceptable to put them to the
side of the cylinder not right in your face, but they shouldn't be
hidden behind it. Your tundish could well be behind that tag on the
right.

There is a zone valve for the central heating connection to the
cylinder, which is correct. This fails shut in the evnt of a power cut
which is the right thing.

I won't carry on about the position of the discharge pipe and so on, it
gets more involved.

The bubble in this type of cylinder naturally becomes smaller until it
is ineffective, but it is very easy to reform. The instructions are on
the side of the tank. In a nutshell, shut of the cold water supply,
switch off all forms of heating, open the nearest hot tap and hold open
manually the tpr valve until all gurgling stops, this could take some
time. Then let go the tpr valve, shut the tap and turn on the water
supply. The bubble will naturally form.

IF YOU EVER SENSE ANY KIND OF DANGER you must A/ turn off all heating
sources, i.e. central heating and or immersion heater/s. B/ Open a hot
tap. C/ turn off the cold supply to the cylinder. Everything will
settle down after that, get an expert in.

When water is under pressure the boiling point is much higher. If any
part of the integrity of that vessel or directly connected controls
should fail water under pressure would on changing to atmospheric
pressure flash over to steam. There is enough power in that flash over
from water to steam to blow your house out of the ground.

This particular cylinder is extremely safe and ruggedly constructed,
all the necessary controls are designed into the fitting kit to prevent
such an event occuring. But you should know it is not something to take
lightly. I would recommend you have it checked by a qualified person.

doozer wrote:
I think I have found the tundish.

That's it. The pictures aren't clear, so I can't guarantee that what
follows is correct. The two pipes going into it are from the expansion
relief valve, and the T&P relief valve (directly above the tundish).
The thing you've labelled as the T&P relief valve seems to be the
Pressure relief valve for the heating. The red expansion vessel is for
the heating (primary) and has nothing to do with the unvented hot water
storage system.

The tundish has scale on it from when one of the two valves was
discharging or dripping. It was probably the Expansion relief, the T&P
relief looks like the older lever type.

Is it normal to have what we have which is basically just a cut out
bit
of pipe for a tundish? Surely that would cause water to flood out all

over the floor rather than down the emergency vent pipe if there was
a
problem.

Yes. As mentioned previously, the D2 pipe to outside should be sized so
that it will carry the water away. It will only overflow the tundish if
there's a blockage in the D2 pipe. If it couldn't then overflow, the
cylinder would then be subjected to excessive pressure, possibly
leading to catastrophic failure.

The 'multi-function control valve' looks crusty and should be replaced.
It may be a pressure reducing valve, in which case there should be a
strainer upstream of it. A replacement would probably have the strainer
built-in.

What would be the effect of having no bubble?

The pressure would rise as the water heated up. The expansion relief
valve would/should open and discharge the excess water. In the UK,
unvented systems are required to have a bubble or expansion vessel to
prevent the waste of this water. Elsewhere, there's no provision to
accomodate expansion and the water goes down the drain. IMHO, it's best
to avoid operating the two safety valves unless necessary. Sometimes
they won't re-seal and have to be replaced.

What I have marked as the immersion heater

I can't make that out.

and we get a burst of hot water the first time we turn the tap on.

That could be normal, the pressure will rise and the air bubble will
get compressed as the water heats up and expands. The additional
pressure will be discharged when you open a hot tap.

Cock on.

Basically the system is sound, but I'd train yourself to re-establish the bubble if I were you. There may well not be a strainer upstream, the early types should have had them seperately fitted but seldom have I found one. The later types have them in the multi function valve. The tpr is also a right old one, but no problem with that. It all seems to be fitted basically right from the photo.

Paul