Type of system explanation

[Colin Robinson]

Hi , I have recently fitted a dual channel hive to my system and it seems to be working fine .
The system has a 40 cdi Worcester conventional boiler a hot water cylinder and a pressure vessel .
There is a small tank in the loft , about 16 inch square with a ball cock in it.
I have attached a pic .
We have only been in the house a year and it is quite large 2900 square ft .
My concern is that i have noticed that when i select hot water on the app (we have it come on twice a day ) that the pump lights up and kicks in , is this correct ? i thought the pump is only for the central heating side of things

Am i correct in thinking that the small tank in the attic above is for topping up the heating side of the boiler and could i add inhibitor to this to treat the system if i drained one of the rads at a drain off point ?
Unfortunately my brother passed away a few months ago and he was a heating engineer so the font of knowledge has gone and i am a little confused .

Thanks for any help

 

[ericmark]

This

bit of your picture shows it is either W or Y plan, most likely Y plan. So default is DHW and half way is both and all the way over is CH only. So yes pump runs for DHW, the rest not so sure, I will let some one who knows more explain.

 

[muggles]

The pump should run for both heating and hot water. Yes, the tank in the loft provides feed and expansion for your system. What makes you think it needs inhibitor adding?

 

[oldbuffer]

That looks to me like an unvented hot water cylinder. If so:
1. It should be serviced annually.
2. Unless specifically stated by the manufacturer it should have a motorised valve dedicated to control of the primary hot water. This is normally a two port valve controlled by the cylinder's internal thermostat. What you have may conform if it is a diverter valve, but probably won't conform if it is a mid-position valve.

 

[Colin Robinson]

Hi , thanks for replying .
The system was drained so two vertical rads could be added in a new extension .
As a lot of water was drained off i just thought it would need inhibitor ?
The pump does turn off when the hot water is switched off so it looks like it is operating correctly then .
I was a little concerned as the pump did feel quite hot but i had noticed that the stat on the tank was set to 70 deg .
I have turned it down to 60 now .
Thanks

 

[Colin Robinson]

Hi , the cylinder says on it that it is a mains pressure domestic hot water cylinder .
The actuator on the valve is a Drayton MA1 mid pos actuator .
I have just noticed on the cylinder and it does say it should be serviced every year .
Are you saying that the set up is incorrect regarding the valve ?

Thanks

 

[ianmcd]

Hi , the cylinder says on it that it is a mains pressure domestic hot water cylinder .
The actuator on the valve is a Drayton MA1 mid pos actuator .
I have just noticed on the cylinder and it does say it should be serviced every year .
Are you saying that the set up is incorrect regarding the valve ?

Thanks

it isnt wrong , but there should should be an additional 2 port motorised spring return vave on flow to the hw coil, it is safety device

 

[Colin Robinson]

ill have a look when i get back .

Thanks

 

[Colin Robinson]

I can't see any 2 port valve .
I have booked a local heating engineer to do a boiler and cylinder service .
We have no previous history for the installation just a receipt from British gas fitting it years ago .
Best let a professional check it over .
Thanks

 

[ianmcd]

this video explains what we are taking about

 

[Hugh Jaleak]

I can't see any 2 port valve .
I have booked a local heating engineer to do a boiler and cylinder service .
We have no previous history for the installation just a receipt from British gas fitting it years ago .
Best let a professional check it over .
Thanks

Please ensure your Engineer has the 'G3' Qualification for working on Unvented hot water cylinders. Sadly, British Gas fitting it doesnt guarantee anything, it often comes down to the quality of the Engineer who did the work and possibly the timescale he/she was given to do the work. Whilst BG would normally be associated with quality, sadly even with BG, corners are often cut to save time/materials.