System Upgrade

[jaydebruyne]

My brother has just bought his first house and it currently has a conventional gravity system with a standard boiler (old 15 year old gloworm).

Mains pressure/flow rate is 3.5bar/14lpm.

2 floors (ground and 1st), 5 rad system. 1 bathroom, 1 toilet, 1 kitchen.

I've recommended a combi system as he wants rid of the cylinder and loft tanks, which I'm planning to install for him as soon as I get my gas ticket (hopefully by end of the month).

All the cold outlets are on mains already.

I've assisted on 2 upgrades from conventional to combi but was unable to always watch what the guy was doing re: connecting pipework.

So I was looking for some advice really on undertaking a task like this and methods/tips etc.

Cheers in advance

 

[kay-jay]

Its a tiny system! Why not just rip out the lot and start from scratch.
He will thank you for it in the long run...

 

[jaydebruyne]

Its a tiny system! Why not just rip out the lot and start from scratch.
He will thank you for it in the long run...

I did actually think about doing that ...

 

[kay-jay]

If its an old system and the water in is is crappy. It would be best to repipe the lot and could be done in the time you would otherwise take to flush it out.

If you do an upgrade (I call them conversions. A combi is seldom an upgrage....)

Things to look for
Is the system fully pumped? Or does it have gravity hw circs?
Do any rads heat up when hw only is selected?

The answers to these questions will point you in the right direction for altering the system [emoji6]

 

[jaydebruyne]

If its an old system and the water in is is crappy. It would be best to repipe the lot and could be done in the time you would otherwise take to flush it out.

If you do an upgrade (I call them conversions. A combi is seldom an upgrage....)

Things to look for
Is the system fully pumped? Or does it have gravity hw circs?
Do any rads heat up when hw only is selected?

The answers to these questions will point you in the right direction for altering the system [emoji6]

Its fully pumped.. Didn't check if any rads were on the dhw circuit

 

[kay-jay]

Well you will need to!
If any rads do heat up you need to repipe the feeds to the heating side.

The 2/3 port valve/s and pump need removing as does the pipe leg from the primary to the cylinder. Feed and vent from the f+e tank need capping off and any bypass valve will likely be a gatevalve type and will need finding and upgrading to an auto bypass, possibly relocating to somewhere more accessible and dependent of course on the mi's of whichever boiler you decide to install.

 

[Atouchofgas]

Or you could put in an open vented combi,

 

[jaydebruyne]

Well you will need to!
If any rads do heat up you need to repipe the feeds to the heating side.

The 2/3 port valve/s and pump need removing as does the pipe leg from the primary to the cylinder. Feed and vent from the f+e tank need capping off and any bypass valve will likely be a gatevalve type and will need finding and upgrading to an auto bypass, possibly relocating to somewhere more accessible and dependent of course on the mi's of whichever boiler you decide to install.

I'll probably fit a worcester greenstar 25i which has an auto bypass fitted internally. I'll check the rad situation out regarding dhw circuit.

Cheers kay-jay

 

[Masood]

I'd have a look at his incoming mains as well Jay. 3.5bar is good, 14l/min not brilliant. Might be an old lead pipe that's got kinked or the stopcock not opening fully.

 

[jaydebruyne]

Or you could put in an open vented combi,

def going with a sealed system