Vented boiler to cobi and three new radiators

[MarkH]

Hi All,

After been let down by several plumbers during a loft conversion my builders are now being held up...
My old vented oil boiler will eventually be replaced with a combi boiler and I will also have three extra radiators in the loft.
The old header tanks have been removed and I am left with the a 22m cold feed and vent pipe. Am I right in thinking that I can use these to supply the new radiators (cold feed for the return and use the vent pipe for the hot supply).
I am confident in installing the copper and soldering but my knowledge on heating systems is limited.

Thanks Mark.

 

[Scott_D]

Are you going to use the old boiler until the new one is fitted?

 

[MarkH]

No we have a small solid fire so making do with that for now for heating and have no hot water. Just waiting to hear back from the boiler company about the cost of the new cobi.

 

[Scott_D]

Replace it for the sake of a few pounds
The pipes could be full of muck

 

[MarkH]

happy to replace the pipe just not sure if the old cold feed and vent can be use for the new supply and return for the new radiators.

 

[Scott_D]

Best to replace
You need a flow and return for the new rads.

 

[MarkH]

yes happy to replace the pipe but does the cf tee off the return and the vent tee off the supply? I cannot replace all the pipework in the house.

 

[Scott_D]

yes happy to replace the pipe but does the cf tee off the return and the vent tee off the supply? I cannot replace all the pipework in the house.

Not normally but can't tell what setup you have without seeing it

 

[SimonG]

Why spoil the ship for a hapenneth worth of tar?

I have a line on my estimate.
I will not guarantee any existing pipework and fittings.

Your pipes have endured atmospheric pressure plus standing head of water.

You are now going to be running water through the heating pipes at a max of 3 bar.

You'll have at least 15mm mains cold up there. Handy for a bathroom.

Personally if I was doing this in my own house then it would be all new and all copper.

 

[SimonG]

Also, wouldn't have an oil combi in my own house. Fit and repair plenty, it would be a heat only (external) and an unvented cylinder.