Conversion to combi

[rlx01]

I want to replace my 20+ yr old Glowworm with a new condensing combi. I would like to do some of the non-gas plumbing work myself to save money. I assume the main things to do just prior to connecting the combi are:

a) flush and de-sludge the system
b) disconnect and solder stop-end onto CH pipe which goes to header tank
c) disconnect and solder stop-end onto CH vent
d) ensure CH flow & return pipes identified for connection to new boiler
e) same with hot water supply and mains cold water
f) run a suitable condensation drain pipe
g) ???

Anything else I might have missed?

 

[weareleeds]

what about hiring a flushing machine to flush system properly & putting trv's on rads best bet is call a GOOD htg eng

 

[Paul Barker]

Remove pump, and midposition or zone valves to do with dhw. Cap off any t in the return from dhw. Make sure bathroom rad or towel rail are not on dhw side. Fit an automatic bipass.

 

[Bamber gaspipe]

"rlx01" wrote:

a) flush and de-sludge the system

How would you do this & what would you use.

b) disconnect and solder stop-end onto CH pipe which goes to header tank

The only pipe going to your header tank is the vent/cold supply in/feed out.

c) disconnect and solder stop-end onto CH vent

Why would you cap this pipe? it will be obsolete & can be discarded

d) ensure CH flow & return pipes identified for connection to new boiler

Which side of now obsolete pump would you tie in to?

f) run a suitable condensation drain pipe

Do you know the regs regarding maximum lengths, gradients, internal/external installation & so forth.

Anything else I might have missed?

Well quite a bit to be honest. If nothing else at least have an engineer/plumber take a look at your system & offer sound advice. I understand your wish to save money but it`s quite a big job to take on with little experience. It`s not as cut & dried as you seem to believe. I don`t know of any Corgi engineers who will sign off someone else`s work, wether you have the gas installed correctly or not..