i am about to replace my conventional boiler so at the same time i a looking to improve my system.
We have a storage tank in the airing cupboard with the pump below it When our boiler kicks in it heats the water AND the radiators. We hav no control of this, in the summer we just turn all the radiators off In the winter when we need the heating on all day our hot water boil all day aswell!. We also dont have any room thermostat either.
Can i fit a y valve to control heating/water ?
do i have to pull cables in to control the valve?
i want to fit a wireless thermostat, are these any good?
I assume from what you say that the CH and HW circuits are *both* pumped, rather than the HW relying on gravity (convection) circulation? If so, you will probably have a T-piece in the airing cupboard, just above the pump, with one branch going to the heating coil in the HW cylinder and the other branch going to the radiators. If this is the case, you can replace the T-piece with a 3-port mid-position valve and convert your system into a Y-Plan.
Yes. The most convenient arrangement is usually to have a wiring centre - which is a fancy name for a 10-way juncion box - mounted in the airing cupboard. This needs to have cables going to:
Programmer
Boiler
Pump
Mid-position valve
Cylinder stat
Room stat (or base unit thereof if you're using a wireless room stat)
Assuming a wireless stat, everything except the boiler could be in the airing cupboard - so the only cable of any length will be the one from the wiring centre to the boiler.
I've never used one, but a lot of people here have - and generally give good reports of them. The wireless feature usually goes with a programmable stat such as the Honeywell CM67 RF - which allows you to have different temperatures set at different times of day. If you use a programmable room stat in conjunction with a conventional timer, the usual trick is to set CH to constant on the basic timer, and let the stat do the timing for that - but use the timer for timing the hot water.
Have a look at
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which shows the basic pipe layout and electrical wiring for a number of heating 'plans'. Study the Y-Plan bit in depth.
While you're at it, also have a look at the S-Plan. This achieves the same thing as a Y-Plan, but uses two 2-port valves rather one 3-port valve. It is slightly more expensive to implement but many people believe that it is technically superior, and less prone to failure. [3-port valves occupy a very strategic position in Y-Plan systems, and can be very temperamental at times].
dbroms wrote in news: snipped-for-privacy@news.diybanter.com:
Yes, but we need to know more - can you do simple wiring and pipework, using compression fittings if you don't like to solder; and simple (but mains, so you need to be competent) wiring?
Possibly not, I think the services you need will be there or thereabouts. You'll need a controller near the valve, which is usually near the pump. The wires to your boiler exist, I presume it's fired by the cylinder stat.
You'll need a cable to a room stat, I guess not if you use a wireless one, but I've no experience of them.
There's plenty more experienced folks than me here, but they'll all need answers to the above, so post them and they'll be right on your case ;o)
many thanks for the replies. I am still trying to fully understand wha system i have at the moment. I think i have pumped central heating an gravity hot water. After the pump the pipe splits into two, one goes to the coil inside m storage tank and the other (25mm) i assume goes to my radiators. I dont seem to have a stat on the tank, the only thing i can find is o the coil outlet from the tank i have what looks like a trv valve with thermocouple wire from it which goes to an aluminium block strapped t the tank.
I have been reading on here and people seem to convert to a C pla arrangement.
Why cant i just fit a 3 way valve after the pump?
I am sorry for what might seem basic questions but this gets more an more confusing the more i read.
If this is *after* the pump, it means that the water going to the HW coil has been through the pump - same as the CH water. If this is the case, your system is fully pumped - and *not* gravity hot water.
That sounds like a device which shuts off the (pumped) flow to the heating coil when the HW is up to temperature - to avoid over-heating the HW when the CH is on.
C-Plan is only applicable to a gravity HW system, and that doesn't seem to be what you've got!
No reason at all. [Unless you take up my earlier idea of going for an S-Plan system by putting a 2-port valve in each branch, instead]
OK, just to be *sure* what you've got: Are there ever any circumstances when the boiler fires but the pump doesn't run? Can you get at the wiring to see how the boiler and pump are wired? If so, are they connected together so as always to work in unison?
The answers to those questions should confirm - or otherwise - that you have a fully pumped system.
thanks for the reply. The pump is always on when the boiler fires, yo never have just the boiler on. The pump connects to a very small junction box in the airing cupboar which just has a live and a neutral in it which i assume comes straigh from the boiler.
This doesn't prove that the HW isn't gravity fed - as from what I understand from the system as you describe it, there is no option to have just the HW heating, i.e. when the heating is on it is always heating both the HW and the radiators...am I right?
The only way to really know is to look at where the flow to the HWC comes from - in a gravity set up it would usually come directly from the boiler in a seperate pipe to the flow to the radiators, but it could technically branch off at some point before the pump. If it is T'd off at any point after the pump and the sytem is fully pumped.
According to what he said earlier, it's tee'd off *after* the pump - so I'm reasonably convinced that it's fully pumped - but the OP still didn't seem quite sure. The supplementary questions were to help *him* convince himself!
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