changing from an open vented to a combi

[southcoastboile]

Doing my 1st combi swap from open vented after just doing servicing and breakdowns and after some advice please.

When removing cylinder do I just need to cap off hw pipe/cold feed, remove 3 port and link what was the heating outlet from 3 port to hot water coil that was on cylinder?

Anything else I need to be aware of?

Thanks again

 

[mfgs]

Cap off the hot outlet/open vent. Cold feed to cylinder will be redundant, link cold down service to mains in loft. If the boiler is keeping its current location, link the primary flow to the heating side of the 3 port, the hot water side will be dead and cap the cylinder return. Obviously cap off open vent and cold feed aswell.

 

[mike_s]

I cap the hot where it tees off to the cylinder under the floor, or replace it with an elbow so there are no dead legs. I also cap the cold before it enters the loft if it is no longer required for showers, less chance of freezes and bursts that way too.
The above method mentioned by mfgs sounds like you're leaving the pipes capped above the floor in the airing cupboard, long cold runs looping in the loft and dead legs on the hot and return?

I'm surprised how many people do it this way so they can save time and quote for less labour, I don't like being undercut this way.
It should be at least a 2 day job to do properly in my opinion

 

[mfgs]

I dont leave random pipes capped above floor and deadlegs unless necesary. Just easier to explain without teaching him how to suck eggs, I'm sure he doesnt need to be told to trace the pipes before linking together and finding the easier and neatest way of doing it. You can only really comment on that when you can see the job.

 

[mike_s]

fair enough, just recently I found out that there are some companies doing it a lot this way and just wanted to point out that it's best practice not to leave dead legs or lengthy runs when not needed.

 

[Mike Jackson]

It's not best practice not to leave deadlegs, it's a requirement of the water regs that none are left.

 

[southcoastboile]

Its in a downstairs flat. was going to tee into existing hot pipe near were the boiler will be fitted (there is a hot tap there with 15mm feed). My mate said this may be a problem because you will have poor hot water flow? I cant link to were the cylinder is because its over the other side of the flat.

I understand what pipes I need to link now and try not to leave dead leg

 

[mfgs]

A 15mm hot water supply from a combi will be fine. The cold inlet and hot water outlet are 15mm connections on combis anyway.

 

[southcoastboile]

A 15mm hot water supply from a combi will be fine. The cold inlet and hot water outlet are 15mm connections on combis anyway.

Thanks 🙂

 

[Centralheatking]

When you have been paid for the job........ go ooh ! you could have a shower
fitted in the old airing cupboard and they often say yes....then your supply
pipes are right there......happy days more work....thats what we do.


centralheatking