Questions for Install Y plan Open Vent Layout - Pic Attached

[onabudget]

Dear all, I WOULD be VERY GRATEFUL if you could answer the following;

The dotted line (2.) is not in yet, is this ok to run the fill for what is the heating loop (into the HWC and the Rads into the same connection as the cold (-) feed to the boiler/HWC? If this is ok should it run with an offset as close to the HWC as possible as in 14 or is a straight run up ok?

Can I put isolation full bore valves in pipes (2) (14) (13) ? I obviously won't put any valves in the vent pipes to make servicing easier in the future.

I've edited out all the bits that were not answered so anyone looking for info for themselves will get the important stuff!

View media item 51962

 

[D_Hailsham]

You can't have the feed and vent on opposite sides of the boiler with modern high resistance condensing boilers. They must both be on the flow side and no more than 150mm apart.

Untitled

• D_Hailsham
• 23 Apr 2009
• 3

Don't be tempted to follow the diagram on the left (below). It's a recipe for pumping over as the straight path up the open vent has lower resistance. (It was used in my reply to another poster.) It's better if the pump pumps upwards or horizontally.

Untitled

• D_Hailsham
• 24 Nov 2008
• 2

 

[onabudget]

MANY THANKS FOR the info;

Does the fill have to go before the pump or can it go on top of the pump before the three port valve (indicated in new picture B)

Or without sounding daft can I use the vent pipe for the fill as well i.e. and split it off as I get further up as per my new diagram below? does that make sense (also shown in new picture A)

The boiler is a Viesmann compact with a high flow circulator heat exchanger but I'm assuming that has no impact on this.

thanks once again... View media item 51970

 

[D_Hailsham]

Does the fill have to go before the pump or can it go on top of the pump before the three port valve (indicated in new picture B)

You can't do that! All the water would be pumped up the feed pipe into the tank (flooded house!!). Feed and vent have to be connected at the point where the pressure is the lowest, which is just before the pump.

can I use the vent pipe for the fill as well i.e. and split it off as I get further up .... The boiler is a Viessmann compact.

You will have to check with Viessmann if this is acceptable.

 

[onabudget]

no useful info in this post by me! it was just noise so edited out

 

[doitall]

The modern way of doing it is a sealed system, unless it's a replacement on an old system.

Hope they ain't the plumbers sketches.

 

[onabudget]

just adapting the old system and wanting to use what I currently have in terms of pumps tanks and HWC so gone for a one for one replacement

 

[CBF]

The modern way of doing it is a sealed system, unless it's a replacement on an old system.

Hope they ain't the plumbers sketches.

yes quite agree why you are going to all the trouble of an open vented heating system i don't know, it would have been much easier to have got a system boiler in the first place, then all you have to worry about is the main roof tank for the cylinder.

No you can't put any valves at all on pipes 2 & 14 even if & when you get them in the right place


http://postimage.org/

plus the cylinder return should be the last connection back to the boiler or your rads could start to heat up when you only want hot water.

 

[doitall]

Follow D Halshams 1st sketch is the best advice.

Cold feed and vent should be within 150mm.

 

[onabudget]

a valve on 14 would have been after the vent connection just so the hot water supply could be isolated but I'm guessing that by stopping the cold going into the cylinder this effectively does the same thing.

isn't a valve on 2 the same as holding the ballcock up in the air to stop any more water filling the tank when draining the system.

there are a few constraints that prevented the use of a system boiler so we gone for getting the boiler to do what it does best, heat the water and that's all.

thanks for all your comments

 

[onabudget]

for the valve on 2 I was thinking of just putting a valve on the supply to the F&E tank as I think that gives the isolation I need.

thanks

 

[CBF]

no you can't put a valve on pipe 2, if the vent blocks for any reason then it can go up the cold feed which it can't if you have a valve on there & someone has turned it off, you don't need to tie the ballvalve up as it should have a isolation valve on the cold mains going into it (as per regs)

 

[CBF]

is this a brand new heating system rads, pipework, boiler, cylinder etc ?

 

[onabudget]

No just adapting what I have with a new boiler added

 

[onabudget]

no useful info in this post by me! it was just noise so edited out