Boiler System Question

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2 Sep 2007
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Hi Guys

I have a hot water tank in my airing cupboard seen below and a cold water tank in the loft. I understand this is an open vented system. I'm trying to understand what the valves do below. I can see 7 in total which are numbered. Can anyone shed any light?



Airing-Cupboard.jpg
 
These are general isolation valves for the hot water to the house and cold water feed to the hot water cylinder.

2 might be the cold water feed isolation to the tank in the loft (need to check where this goes)
4 I would I would assume would be the cold water isolation valve from the tank in the loft.
5 would isolate the hot water coil from the boiler.
6 & 7 hard to tell may be isolation for rads and from the boiler.
 
Thanks RJC. If it helps I have taken another look on how they are connected.

  1. This one splits. One side goes to the top of the cylinder and the other to downstairs.
  2. Doesn't connect to the hot water cylinder. It looks like it goes from the loft straight to downstairs.
  3. Again this one doesn't connect to the cylinder it goes from loft to downstairs.
  4. This one connects to the bottom of the hot water cylinder on the right hand side.
  5. Bottom of hot water cylinder on the left.
  6. This connects to a Honeywell diverter valve.
  7. Connected to diverter valve.
 
This may help a little as well:

9JUOPLU.gif
1 seems strange - should typically be a vent, maybe it's a loop back of the hot water from somewhere?
2 looks to be your mains water supply (try turning it off then pushing the stop **** down in your cold water tank.
3 cold water outlet from cold tank
4 cold feed to cylinder
5 cuts the cylinder from the hotwater
6 cuts the hot water loop
7 cuts the feed to the radiators (i'd expect)
 
Last edited:
Thanks guys. I think I'm getting there.

  1. This feeds hot water to our ensuite shower which is a power shower. The pipe directly above the cylinder is the vent pipe.
  2. Supplies cold water to the tank in the loft.
  3. Not sure on this yet. Cold to touch.
  4. Cold water feed to cylinder.
  5. Hot water coil.
  6. Not sure on this yet. Some sort of diverter.
  7. Not sure on this yet. Some sort of diverter.

Thanks Siliconslave/RJC.
 
  1. This feeds hot water to our en-suite shower which is a power shower. The pipe directly above the cylinder is the vent pipe.
  2. Supplies mains cold water to the tank in the loft.
  3. Most likely supplies cold water to the shower in en-suite.
  4. Cold water feed to cylinder from header tank.
  5. Valve used to throttle flow through the dhw coil. This should have been balanced by the installer, so don't touch.
  6. Gate valve on heating flow, no real use. Leave it fully open.
  7. Gate valve on the bypass, again don't touch. No real use on a Y-plan, and not even a proper bypass valve.
Hope that helps.

The only thing I'd want to be looking at changing would be those two pump valves that look like they've been leaking. The external body of the pump isn't water tight, so water can get in and corrode/short the windings/control box.

Mick
 
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