CH layout of cold fill and vent pipe

[DIYedboy]

It seems that these pipes should be fitted within 6 inches of each other on the flow. BUT I have a Baxi back boiler, am I right in thinking this rule is not correct for back boilers?

 

[doitall]

The rule is for a certain type of installation and applies to all gas boilers.

 

[seco services]

if its fully pumped its correct

 

[DIYedboy]

I have to change the pipe layout, so HW and CH will be pumped. I believe that the cold fill is supposed to be nearest the boiler on the return and the vent is nearest the boiler on the flow then the pump and then the HW cylinder and then the CH flow..........is this right?

 

[doitall]

On a fully pumped I assume Y or S plan, it goes;

Boiler.

open vent.

Cold feed.

Pump.

MV.

 

[seco services]

I have to change the pipe layout, so HW and CH will be pumped. I believe that the cold fill is supposed to be nearest the boiler on the return and the vent is nearest the boiler on the flow then the pump and then the HW cylinder and then the CH flow..........is this right?

what the f*ks that design ?

 

[DIYedboy]

Seco, I don't understand your answer

Doitall, there is only one 2 port valve and that is in the CH circuit (I have no idea whether that makes it S,Y or something else)

 

[seco services]

so you have a gravity hw and pumped heating ?

and your changing it to fully pumped then it will be y or s plan.

 

[kevplumb]

sounds to me like a cheap fully pumped system

the zone valve cuts the heating circs so you can have just hw in the summer

 

[DIYedboy]

Yes, gravity HW at the moment (pump on the return of CH!) and system has BIG pumpover problem, another problem is all CH in 15mm and vent is 15mm too. Basically, I want to strip out the system and get it right but only want to use the existing two port valve and also retain the original Randall? programmer. Are you saying that the fill/expansion 22mm pipe should NOT be nearest the boiler on the return even though it is a low resistance back boiler in a 2 up 2 down edwardian villa?

 

[kevplumb]

ang fire

if you have gravity h/w whats the 2 port valve for

unless its a "c" plan

 

[seco services]

if you have your vent and feed on the gravity hw side then you won't be having pump over.

 

[seco services]

ang fire

if you have gravity h/w whats the 2 port valve for

unless its a "c" plan

i bet the zone valve is just doing the job of a gravity valve and just wired to just open with the stat.

 

[DIYedboy]

You will have to excuse my ignorance lads, to answer you (if I can Kevplumb) the boiler only has 2 pipes coming out of it, the HW is gravity and the CH comes off this,the valve suts off the ch so in the summer only the HW circuit flows.

 

[kevplumb]

wheres the pump on the heating side

before you start pulling things to bits

this might be worth a look