Y Plan Central Heating or not Y Plan??

[Mike2007]

I thought I had a Y Plan design in my latest house and now find I might not? I have a HW tank stat, a room stat....so I just assumed the three port would be stuffed somewhere as it was not in the airing cupboard!
After ripping through a few boxed areas I have found nothing of a valve, either three-port or 2?
I do have a two channel programmer, which got me hunting for the valve/valves...
Could my HW and CH just be switching on the two stats, either HW/CH ON or HW/CH off?? Sounds possible to me, what do you think?

 

[John_D]

Hi Mike
Is there a pump or are we talking old style boiler aga coal etc
are the pipes to heat the hot water tank large (28mm or bigger)
this means you have gravity DHW heating and maybe pumped or gravity central heating
another clue does the boiler fire up when programmer asks for hot water only?

I have seen dual channel programmers fitted to combi-boilers and the customers call for help when there is no hot water (because the programmer was turned off) Guess the original installer happened to have the wrong kit on his van


John

 

[Mike2007]

Hi John,
Glad someone else gets up early on a Sunday!
Yes it is pumped from ground floor with Myson pump. We still have a Baxi Bermuda back-boiler feeding everything.
Will try your idea about the call for DHW and see, but I seem to remember it does heat on this stat call?

Mike

PS. Everthing was DIY in this house bar the electrics as it was done by a sparky.

 

[John_D]

gravity heating was used on back boilers as the original idea was heat for the lounge and hot water as a bonus not sure how this changed with Baxi
check the pipe sizes and how many header tanks?

 

[ChrisR]

Common would be to use the programmer hw on + cyl stat to turn the boiler on, and programmer ch on + room stat to turn the pump and boiler on.
Your programmer should then be configured inside so you can't put ch on without hw, and it'll still overheat the hw if the ch is on...

Dorky way to do it but you provided the reason...

it was done by a sparky.

 

[DP]

Advance CH demand on programmer. There should be a delay if a motorised valve is fitted.

Switch off CH demand.

Now advance HW demand on programmer. If there is a delay, you have motorised valve fitted.

Deselect HW demand. Wait a minute of so. Reapply demand. If the boiler fires right away, you have a three port valve. If delayed firing, it will be two port

 

[Mike2007]

Tried DP's method , but not too sure are cylinder in attic room, boiler/pump on ground floor (could not conclude much with my screwdriver at my ear!).
All I know is they both call for heat indipendantly, so there is a valve or valves hidden. I assume they must be on their side in the first floor (seems like a good place concidering there is 10mm microbore rad feeds).
On answer to other question 2 F&E tanks.
It seems pretty dumb to place valves away from cylinder when there is nice airing cupboard, maybe trying hard to save copper??

 

[John_D]

On answer to other question 2 F&E tanks.?

one for the pumped ch
one for the gravity water heating
means 2 separate boiler circuits

and a fortic hot cylinder

the 10mm pipes will go into a manifold under the floor


what DP said was set the programmer and check if the boiler fires
make sure the stats are set high

 

[Mike2007]

valves not essential

Surely there are valves as my water would boil when the rads are turned right up and there are separate calls for heat for both stats?
If I find the microbore manifolds the valve would not be far away. Unless anybody else can suggest a new design type?

 

[ChrisR]

Boiler has its own stat, max should be about 82.

 

[Mike2007]

Thanks for everyones reply, I will rip some more boards next week. Find out what is under pinning my system!

 

[DP]

Mike read my post again. If you follow my instructions, you will then be able to verify what type of controls (if fitted) are in existance on your system. One does not rip up the flooring without good cause.

If you try what I have suggested, might be ablke to help you further to locate what is where.

If you have had a plate of porridge and have plenty of energy on this holiday weekend, then don't let me stop you lifting the floor in your quest.

 

[Mike2007]

DP,
Just the problem of not being able to hear the kick from downstairs fire hearth, ok to hear the CH calling. Stat is on the cylinder on last/top floor, I tried to use a screwdriver for this as I said (one end your ear, other 22mm flow pipe), listen for pump!
My main question was " can the stats control start-up on their own" with no direction flow control(valves)?
Besides I like crow bars and porriage, must be sweetend though!

 

[gas4you]

Yes, but you would get no seperation between heating and hot water times as the pump would just do both together unless you have gravity primaries and pumped rads.

 

[John_D]

A stat is a temperature switch, the programmer sends live to the switch (stat) which then sends the live to the boiler or to the motorised valve which then sends live to the boiler
I find the crowbars in the porridge too crunchy