Upgrading heating - what are these bits?

[Monkey3]

Hi, I'm wondering if you can help me.

I've not long moved into this house and I'm looking to upgrade the central / water heating system (loads of reasons but partly the manual 3 way valve is broken and the boiler is controlled with a rocker switch... and that's it, no stat, no nothing)

So I'm fairly sure I know what needs to be done but I'm a bit unsure with a couple of parts of the system:

Key to the images:

red	hot from boiler
yellow	hot to central heating
pink	hot to HWST
blue	not hot from HWST (out from pink)
green	???
black	not part of the heating (ignore)

What is the green pipe for?
And what is the item in the 3rd picture for?

I have some ideas that these are something to do with when the water in the HWST reaches a certain temperature so that the water is sent round the central heating instead or something but I can't work out how that would happen.

I reckon all I need do is replace the 3 way with an electric version, add a HWST stat, a room stat and a controller (I may even be able to remove the green pipe) and I should be ok but I thought I see what people see first anyway.

thanks for any help you can give me,

Russell.

 

[GasmanxxxR1]

Green pipe is the bypass, creating an open circuit for the boiler to flow if the valve is closed, should be replaced with an auto bypass

The thing in the third picture looks like a pressure reducing valve that has been used to balance the ho****er circuit, this should be removed and replaced with a gate valve or balancing valve

 

[GasmanxxxR1]

not sure why they have asterixed ho****er

Most modern boilers prefer an auto bypass even on a y plan system, helps the energy effciency

These old servo warm units were a cheap way of getting people fully pumped systems

 

[PlumbBobBob]

it's because of the word in the middle of hot water when written without a space lol

 

[GasmanxxxR1]

oh! i see now. lol

 

[Monkey3]

Excellent, thanks Gasman.

As a result of now knowing what I'm looking for I've found out a little bit more:

Firstly my boiler, a Potterton 50L, made an appearance on watchdog :|

And secondly, from [DLMURL="http://www.partsarena.com/baxi/System/DATA/Dx/DS1/installation/2226/I04-2226/I04-2226.htm#z19thesystem"]here[/DLMURL], maybe I don't need a bypass at all as I'm going for the y-plan.

However,

Most modern boilers prefer an auto bypass even on a y plan system, helps the energy effciency

So would it just be a case of replacing the green 15mm with a 22mm including an auto bypass?
Do you think it's a good idea to do this or keep it simple?

p.s. I'm going to start leaving out the space in ho****er just for the fun of it.

 

[stevetheplumber]

the item with the blue cap is a cytrol valve an early form of temperature controll for cylinders

 

[Monkey3]

the item with the blue cap is a cytrol valve an early form of temperature controll for cylinders

Ah, well I have no immersion and it's a vented system so surely that's not required.

 

[stevetheplumber]

you wont need the cytrol as your hot water wll be controlled by three way and cylinder stat
the green pipe could be a summer circuit for your bath room rad/ towel rail as this looks like it may have once been a gravity system thats been converted to fully pumped or its an early form of fully pumped and they still ran bathroom rad from primaries
this means youll get a hot rad in summer for your bathroom anytime hot water is on even though heating is of personally id keep it as warm towels are alway nice

 

[Monkey3]

Well from the sounds of it it would be better to remove the cytrol and I certainly can't see any need for it.

I don't think the green one is a summer circuit as it simply joins the feed to the return just after the pump which fits the description of a bypass although I could be wrong.

 

[stevetheplumber]

yes your correct another lookand i can see it thought it disapered into the floor