Is my CH/HW fully pumped? Is it two-pipe?

[phloaw]

Hi,
I'm having problems understanding the exact configuration of the CH/HW piping in my house.
In particular, I have to understand where and how to place piping for additional radiators at the upper floor.

My configuration is the classical one: loft cistern, indirect cylinder on the upper floor, gas boiler on the ground floor. (my house is a two-floor terraced house, quite standard I'd say)
This is the official installation diagram taken from the boiler's installation guide (I think "heat exchanger" can be identified with "boiler" for our purposes):

Contrasting that, this is how the boiler plumbing actually looks, from the left side (the smaller pipe on the bottom is irrelevant since it just passes through the boiler):

and from the right-hand side:

Given the number of pipes (4) attached to the boiler, and given the first figure, it looks like a non fully-pumped system.
However, the location and number of valves: one for HW (top right last picture) and one for CH (bottom right of last picture) suggests a fully-pumped one.

Any clue of what the actual situation is? Any test I could take myself to ascertain that?
And what about the radiators configuration? Is there a way to know if it's a two-pipe or one-pipe system?
As I mentioned, my main reason to know that is the perspective addition of radiators to the existing CH.

Thanks!

 

[Paul.S]

Hi, The mechanical drawing that you have is a two pipe system, gravity primary/pumped heating , which is why the flow and return pipes from boiler to cylinder is 28mm. Going on your photograph the system may have been converted (crudely) to fully pumped with the 22mm pipe of the left top tapping being the vent the bottom 15mm pipe being the cold feed. But that's just a possibility going by the photo, can you confirm that there are two motorised valves on the flow after the pump and do you have both a room thermostat and a cylinder thermostat ? when the boiler is on hot water only does the pump run? if it does its fully pumped

 

[Brambles]

From your photographs (right hand side) you have a fully pumped system.

Before adding any new radiators / pipework, I would sort out the boiler, clean the system and add a magnetic filter.

 

[phloaw]

Thank you to both!
Sorry, I somehow missed the reply notifications.
So you're right, I think I have a fully pumped system.
This seems to be confirmed by text in the installation manual that I missed initially (sorry about that):

The appliance must NOT be used for direct hot water supply or for sealed system.
The following indirect open vented systems are suitable:
Combined gravity domestic hot water and pumped central heating.
Combined pumped gravity domestic hot water and pumped central heating.
Pumped central heating only.
Gravity domestic hot water only, up to a minimum domestic hot water cylinder storage capacity of 180 litres (40gal.).

I am still unsure as to whether I have two-pipe CH or not.

From your photographs (right hand side) you have a fully pumped system.

Before adding any new radiators / pipework, I would sort out the boiler, clean the system and add a magnetic filter.

What do you mean with "sort out the boiler"?
By "clean" you mean something like this?
Fernox F3 Central Heating Cleaner

 

[Brambles]

It is unlikely to be a one pipe system - just try to sketch out the pipework you can see and it should become apparent as to how the system is configured.

To sort out the system :

Isolate the boiler and thoroughly flush it out. Do the same for the rest of the system. Don’t flush the system through the boiler. When reinstating, instal a quality magnetic filter on the return to the boiler. Dose the system with your preferred inhibitor.

 

[phloaw]

To sort out the system :

Isolate the boiler and thoroughly flush it out. Do the same for the rest of the system. Don’t flush the system through the boiler. When reinstating, instal a quality magnetic filter on the return to the boiler. Dose the system with your preferred inhibitor.

Hi @Brambles, thank you again for your advice.
I am belatedly trying to follow your advice to sort out my system. I think I understand why you recommend not to flush through the boiler. However, isolating it looks tricky: I don't have valves to do that (which is probably a safe thing!). So, how would I isolate the boiler if the system is still full? Where would I start from?

 

[Brambles]

Isolate at the pump and the three way valve

 

[phloaw]

Isolate at the pump and the three way valve

As from pics, I don't have a three way valve, but a pair of on/off valves. And I only have two gate valves, one before and one after the pump. Anyways, guess I can only use the valves I have 🙂

Thank you again!

 

[king of pipes]

You have a 2 pipe fully pumped system which in all honesty could do with upgrading the old girl is in her twilight years and not very fuel efficient. Regards kop

 

[phloaw]

You have a 2 pipe fully pumped system which in all honesty could do with upgrading the old girl is in her twilight years and not very fuel efficient. Regards kop

That's very sound advice, I think, which I will probably follow in the near future. However, I am confused by the images attached to your post. Are they relevant? Thank you.

 

[king of pipes]

Before and after pictures of a system the same as yours which i upgraded, if you should decide to replace your old boiler and cylinder this is what you should expect . Kop