S-Plan layout advice needed

[ss1970]

i am hoping someone can help me. I am an enthusiastic DIYer trying to establish if my boiler configuration is correct, having had it professionally installed back in 2013. Specifically, I am concerned at the:
- placement of the pump on the boiler return
- placement of the heating 2port motorised valve on the return from the radiators
- use of a gate valve instead of an automatic bypass valve
- placement of the bypass gate valve in relation to the other components

I have created and uploaded a diagram describing the key components.

Note that all the radiators are fitted with TRVs, and the boiler is a Vaillant ecoTEC plus 428.

Any help much appreciated.

 

[dan2071]

From your diagram, the only issue from what I can see if your pumps on the return so if you had a leak, it could suck air in instead of leaking water out. You have a combined cold feed and expansion so won't have issues with pumping over.

BG fit this design of system quite a lot with Baxi Precisions.

A lot of people prefer a manual bypass rather than an automatic.

Dan

 

[Steelmasons]

Arrows point the wrong way regarding flow for by-pass.
The system layout will cause nothing but trouble.

 

[Dan Robinson]

BG fit this design of system quite a lot with Baxi Precisions

I hope not

 

[picasso]

Gate valves are not allowed any more, has to be an automatic bypass, very poor design/install

 

[dan2071]

I hope not

They do. The first time I saw it, they had also kept the cold feed and expansion coming off the old gravity circs. Both 2 ports and pump were on the return. I got them back and they combined the feed and expansion but said potterton are happy with this arrangement of controls.

If I remember correctly, the instructions said they should be arranged to prevent the intake of air and because it was combined....

 

[dan2071]

Gate valves are not allowed any more, has to be an automatic bypass, very poor design/install

Your right, I didn't read the date it was installed.

 

[Dan Robinson]

They do. The first time I saw it, they had also kept the cold feed and expansion coming off the old gravity circs. Both 2 ports and pump were on the return. I got them back and they combined the feed and expansion but said potterton are happy with this arrangement of controls.

If I remember correctly, the instructions said they should be arranged to prevent the intake of air and because it was combined....

So how does the bypass work?

 

[dan2071]

Potty precision doesn't require a pump over run. i didn't clock the position of it. If they moved the pump closer to he boiler (after he bypass) then it'd work.

 

[dan2071]

It's wrong either way.

 

[ss1970]

Thankyou all. Two things are clear:

1) The pump should be placed on the boiler flow, not the return
2) An automatic bypass valve should have been fitted, instead of a gate valve

if your pumps on the return so if you had a leak, it could suck air in instead of leaking water out.
Dan

@Dan. I can often hear there is air in the system when the pump is running. I regularly have to try and clear it by running the pumps "bleed" function.
- Could the pumps position on the boiler return be contributing to this ?
- Would there be any advantages in moving the central-heating 2port valve to the radiator flow (i.e. feeding the radiators), especially if I had the pump moved to the boiler-flow ?

The system layout will cause nothing but trouble.

@Steelmasons
- Could you please give some examples of "trouble" ? I want to include these in my response to the installer.

Many thanks

Sean

 

[Dan Robinson]

1) The pump should be placed on the boiler flow, not the return
2) An automatic bypass valve should have been fitted, instead of a gate valve

Not necessarily.

 

[Steelmasons]

@Steelmasons
- Could you please give some examples of "trouble" ? I want to include these in my response to the installer.

Many thanks

Sean

Not a problem although a consultation fee will apply.
Do you wish to proceed?

 

[AGAS]

- Could you please give some examples of "trouble" ? I want to include these in my response to the installer.

what are you paying your plumber for ??